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HP StorageWorks

Continuous Access XP user guide

for the XP1024/XP128

Part number: T1611-96002

Second edition: March 2006

Summary of content (108 pages)

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HP StorageWorks Continuous Access XP user guide for the XP1024/XP128 Part number: T1611-96002 Second edition: March 2006
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Legal and notice information © Copyright 2005, 2006 Hewlett-Packard Development Company, L.P. Confidential computer software. Valid license from HP required for possession, use or copying. Consistent with FAR 12.211 and 12.212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor’s standard commercial license. The information contained herein is subject to change without notice.
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Contents About this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prerequisites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Firmware versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Related documentation . . . . . . . . . . . . . .
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Cache and nonvolatile storage (NVS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Host failover software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Duplicate volumes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Host system crash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Preparing for Continuous Access XP volume pair operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Common procedure for Continuous Access XP pair operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 List after command selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Modifying parameters and deleting LUs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 Tables 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 6 Shared BC S-VOL/Continuous Access XP P-VOL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Access XP main pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Volume list (partial view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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17 18 19 20 Remote copy I/O statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Disk array performance conditions and recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Fence-level settings on Continuous Access XP Sync P-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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About this guide This guide provides information about the following: • ”Overview of Continuous Access XP operations” on page 13” • ”Preparing for Continuous Access XP operations” on page 30 • ”Starting Continuous Access XP” on page 41 • ”Performing Continuous Access XP configuration operations” on page 53 • ”Performing Continuous Access XP pair operations” on page 78 • ”Continuous Access XP disaster recovery operations” on page 97 • ”Error codes and messages” on page 103 • ”Pinned track recovery for Contin
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Document conventions and symbols Document conventions Table 2 Convention Element Blue text: Table 1 Cross-reference links and e-mail addresses Blue, underlined text: (http://www.hp.
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Subscribing to this service provides you with e-mail updates on the latest product enhancements, newest driver versions, and firmware documentation updates as well as instant access to numerous other product resources. After subscribing, locate your products by selecting Business support and then Storage under Product Category. Helpful web sites For additional information, see the following HP web sites: • http://www.hp.com • http://www.hp.com/go/storage • http://www.docs.hp.com • http://www.hp.
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1 Continuous Access XP for the XP1024/XP128 HP StorageWorks Continuous Access XP creates and maintains duplicate copies of user data from a local disk array on a remote disk array. These copies are useful for data duplication, backup, and disaster recovery. Continuous Access XP has synchronous and asynchronous copy modes to accommodate a wide variety of user requirements and data copy or movement scenarios. Continuous Access XP is used for open systems data.
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• ”Continuous Access XP Asynchronous recordset operations” on page 21 • ”Continuous Access XP Asynchronous consistency group operations” on page 23 • ”Continuous Access XP volume pair status” on page 25 Components Continuous Access XP operations involve the XP1024/XP128 at a primary and secondary (remote) site, physical communications paths between these disk arrays, and Command View XP or XP Remote Web Console.
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Figure 2 Continuous Access XP components for Serial (ESCON) connections XP1024/XP128 Continuous Access XP operations involve primary (main) disk arrays and secondary (remote) disk arrays (MCUs and RCUs). This document describes Continuous Access XP operations in which the main disk array is an XP1024/XP128 and the remote disk array is an XP1024/XP128. MCUs contain Continuous Access XP primary volumes (P-VOLs), which contain original data and are online to the hosts.
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information to be reported if a problem with a secondary volume or remote disk array occurs and provide disaster recovery capabilities. The MCU and RCU can be defined separately for each Continuous Access XP volume pair. The XP1024/XP128 CU can function simultaneously as an MCU for one or more P-VOLs and as an RCU for one or more S-VOLs, provided the remote copy connections and Fibre Channel or serial interface ports are properly configured.
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the remote site when needed. See ”Continuous Access XP Asynchronous consistency group operations” on page 23 for further information. Only Continuous Access XP Asynchronous pairs belonging to the same CLPR can be allocated to one Continuous Access XP consistency group. For more information about CLPRs, see the HP StorageWorks XP Disk/Cache Partition user guide. Remote copy connections Remote copy connections are physical paths MCUs use to communicate with RCUs.
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RCU target ports are (Continuous Access XP) dedicated Fibre Channel interface ports on the remote disk array (RCU) to which MCUs (initiator ports) are connected. You can configure Fibre Channel interface ports of the XP1024/XP128 as RCU target ports. For performance reasons, RCU target ports should not be shared with host connects. Remote control ports (RCPs) and local control ports (LCPs) Remote control ports (RCPs) are dedicated serial interface ports on the MCU to which RCUs are connected.
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Remote copy operations There are two types of Continuous Access XP remote copy operations: initial copy and update copy. Figure 3 Remote copy operations Initial copy operations Initial copy operation synchronize P-VOLs and S-VOLs independently of host I/O processes. Initial copy operations are the same for Continuous Access XP Sync and Continuous Access XP Async pairs. Continuous Access XP initial copy operations occur when adding a pair (paircreate) or resuming a split/suspended pair (pairresync).
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For asynchronous update copy mode, the MCU stores P-VOL updates with additional control information in cache, and sends updates and control information to the RCU completely independent of host I/O processes. These updates and their associated control information are called recordsets. The RCU stores recordsets in cache and performs updates to S-VOLs in the same order as they were performed at MCUs according to the sequence information stored in the recordset.
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to the MCU. When you resync a split Continuous Access XP pair that has the S-VOL write option enabled, the RCU sends the S-VOL cylinder bitmap to the MCU, and the MCU merges the P-VOL and S-VOL bitmaps to determine which cylinders are out-of sync. This ensures proper resynchronization of the pair.
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Selecting and settling recordsets at the RCU The RCU selects recordsets to be promoted to formal data (or “settled”) as follows: 1. The RCU checks for a valid entry at the top of each queue in the consistency group. If the top of any queue is empty (recordset not yet received), the RCU waits for that entry. 2. When the top of each queue contains a valid entry (recordset), the RCU selects the entry with the earliest sequence number, and settles that recordset. 3.
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Inflow control by MCU When the amount of MCU sidefile cache reaches the user-specified threshold (I/O delay start), the disk array’s I/O response is delayed. When the amount of MCU sidefile cache reaches the user-specified threshold (I/O delay increase), the disk array’s I/O delay starts increasing.
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Group options Continuous Access XP provides the following options for each consistency group: copy pending timeout and RCU ready timeout. These options are selected when you add a group, and can be modified only when the group does not contain any P-VOLs in the MCU. Copy pending timeout This group option specifies maximum delay allowed for Continuous Access XP Async copy operations.
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Continuous Access XP volume pair status Continuous Access XP displays pair status for each volume in the selected logical CU image (CUI) of the connected XP1024/XP128. Table 5 describes Continuous Access XP pair status descriptions. The MCU maintains the status of the P-VOL and can change the pair status of the P-VOL and S-VOL. The RCU maintains the status of the S-VOL and can change the pair status of the S-VOL but not the P-VOL.
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Table 5 Continuous Access XP Asynchronous pair status descriptions (continued) Pair status Description P-VOL access S-VOL access PSUS (pair suspended-split) Pair is not synchronized because you split this pair (pairsplit-r) or deleted this pair from the RCU (pairsplit-S). For Continuous Access XP Async pairs, the MCU and RCU track recordsets discarded during the pairsplit-r operation. While a pair is split, the MCU and RCU track P-VOL and S-VOL cylinders updated.
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Table 5 Continuous Access XP Asynchronous pair status descriptions (continued) Pair status Description P-VOL access S-VOL access Pair Status for Continuous Access XP Asynchronous only: Suspending Pair is not synchronized. This pair is transitioning from PAIR or COPY to PSUS/PSUE. When the split/suspend pair operation is requested, the status of all affected pairs changes to Suspending. When the split/suspend operation is complete, the status changes to PSUS/PSUE.
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Table 7describes the consistency status for split or suspended Continuous Access XP Async S-VOLs (consistency status is displayed only at the RCU). Table 7 Consistency status descriptions for split/suspended Continuous Access XP Async S-VOLs Consistency status (displayed at RCU) Description Volume Continuous Access XP Asynchronous volume pair was probably split or suspended alone. Update sequence consistency between this S-VOL and other S-VOLs in this consistency group is not ensured.
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When a Continuous Access XP Asynchronous (Continuous Access XP Async) pair is suspended, the MCU stops performing Continuous Access XP Async recordset operations for the pair. The MCU continues accepting write I/Os for the suspended P-VOL and tracks P-VOL cylinders updated while the pair is suspended. The MCU and RCU also tracks recordsets discarded during the pair suspension.
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If a recordset is lost in transmission from the MCU to the RCU, the MCU’s cylinder bitmap ensures the missing recordset is marked. After the MCU sends the recordset to the RCU, the MCU does not remove the sidefile entry for the recordset from its cache until it receives an I/O completion signal (device end) from the RCU. Table 9 describes Continuous Access XP Asynchronous suspension conditions and indicates which CU detects the condition and which pairs are suspended.
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• For distances greater than 11 km, approved third-party channel extender (or DWDM) products and telecommunications lines • Remote copy connections – serial: • Multimode serial interface (ESCON) cables at both the MCU and RCU. • For distances from 3 km to 43 km (1.9 to 26.7 miles), single-mode serial interface cables with ESCON directors (ESCDs) and/or ESCON repeaters. • For distances greater than 9 km (5.6 miles), extended distance facility (XDF) provided by the ESCDs and/or ESCON repeaters.
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Continuous Access XP, a LUSE P-VOL must be paired with an S-VOL of the same size and structure. For example, if a LUSE P-VOL is connected with volumes of 1GB, 2GB, and 3GB in this order, you must specify the LUSE volume that has exactly the same size and connection order as the S-VOL. When LUSE volumes are assigned to a Continuous Access XP pair, the P-VOL and S-VOL must contain the same type and number of LDEVs (for example, OPEN-3*6 to OPEN-3*6).
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CAUTION: If Continuous Access XP S-VOLs are physically attached to the same host servers as Continuous Access XP P-VOLs, a problem might occur. When a Continuous Access XP pair is deleted, the old S-VOL is usually offline. If the host is then restarted, the system administrator may be offered both volumes and asked which volume should be left offline. This can be confusing and is prone to error.
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”Fibre Channel remote copy connections” on page 34 for remote copy configurations. Distribute paths between different storage clusters and switches to provide maximum flexibility and availability. Logical paths between the MCU and RCU must be separate from logical paths between the host and RCU.
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• Switch connection: Up to three optical fibre cables (per hard zone) are connected via switches to connect the devices. Up to two switches can be used. Figure 7 Switch connection • Extender connection: Protocol converters and switches are used to connect devices across large distances. Figure 8 Extender connection Serial remote copy connections Figure 9 shows Continuous Access XP serial remote copy connection configurations. The MCU and RCU of each pair must be connected via multimode ESCON cables.
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You can install dedicated ESCON channels or use existing ESCON channels connected by ESCDs. Logical paths between the MCU and RCU must be separate from logical paths between the host and RCU. All remote copy activities between two XP disk arrays can share the same remote copy connections. ESCDs can accommodate multiple MCU-RCU remote copy connections (Figure 10).
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ESCDs can accommodate channel-to-MCU and channel-to-RCU connections in addition to remote copy connections (see Figure 12). Figure 12 Remote copy connections shared with channel-to-RCU connections Configuring MCUs and RCUs for Continuous Access XP operations After preparing the hardware and software, configure MCUs and RCUs for Continuous Access XP operations. Fibre Channel and serial interface configuration 1. Identify volumes that will become Continuous Access XP P-VOLs and S-VOLs.
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7. Register the RCUs to the current MCU CU image by using the Add RCU pane. Set the options for the registering RCU by using the RCU Option pane (see ”Registering RCUs (Add RCU)” on page 56 for instructions). Figure 13 Add RCU and RCU Option panes 8. If you plan to create Continuous Access XP Async pairs with P-VOLs in this MCU, configure Async options using the Async Option pane (see ”Asynchronous copy option” on page 70 for instructions).
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9. When you are finished configuring this MCU, exit the Continuous Access XP main pane, and disconnect the Command View XP management station from the disk array. 10.If needed, reconnect Performance Advisor to this disk array (running PA at the same time is not supported). 11.Repeat step 4 - step 9 for each disk array that will function as a Continuous Access XP MCU.
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S-VOL using the S-VOL’s LDEV ID in the host command. The BC remote console software displays the LDEV ID and BC pair status of all S-VOLs associated with a P-VOL.
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• Figure 17 combines the configurations shown in the two previous figures. Within a single Continuous Access XP pair, the P-VOL and S-VOL function as BC P-VOLs, providing multiple copies at primary and remote sites. Figure 17 Shared Continuous Access XP/BC P-VOL and shared Continuous Access XP S-VOL/BC P-VOL • Figure 18 shows an example of a BC S-VOL that is also used as a Continuous Access XP P-VOL.
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NOTE: Partition-level users in the StorageAdmins group cannot perform Continuous Access XP operations. For more information about limitations, see the HP StorageWorks Command View XP user guide for XP Disk Arrays or the HP StorageWorks XP Remote Web Console user guide for XP1024/XP128.
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Continuous Access XP functions (continued) Table 12 Tab Menu command Description RCU Operation RCU Status Displays RCU status and Continuous Access XP port numbers that are already set. RCU Operation > Add RCU Registers the RCU at the remote disk array. RCU controls the S-VOL of the Continuous Access XP volume pair. RCU Operation > Delete RCU Deletes RCUs that are already registered. RCU Operation > Change RCU Option Modifies options for RCUs that are already registered.
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The Continuous Access XP main pane contains the following items: • CU Number/Port Number tree: Subsystem folder displays CUs, ports, and host groups. Only the CU/Port containing LUs is shown in the CU Number/Port Number tree. A CU number or port number can be selected in the CU Number/Port Number tree to specify information displayed in the Volume list. You cannot select more than one CU number or port number.
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• Status: See ”Continuous Access XP volume pair status” on page 25 for further information about Continuous Access XP pair status. Table 14 shows the icons. Table 14 Icon Status icons for Continuous Access XP operations Explanation SMPL. Volume is not currently assigned to a Continuous Access XP pair. When the paircreate operation starts the initial copy, the volume status changes to COPY. COPY. Continuous Access XP initial copy operation is in progress. Data on the pair is not fully identical.
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When you select the CU number or Port number on the CU Number/Port Number tree on the Continuous Access XP main pane, the selection in the CU Number/Port Number tree has precedence over the specification in the Display Filter pane. When you select the CU number or Group number in the tree, the specification on the Display Filter pane for the CU number or Group number is not available. To make all settings on the Display Filter pane available, click Subsystem in the CU Number/Port Number tree.
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NOTE: You can use the snapshot function only while client file access is enabled. When client file access is not enabled, the snapshot button is not displayed on the Pair Operations panel. Table 15 describes the Snapshot function. Table 15 Snapshot functions Item Function Data Format Text file. Target data Continuous Access XP pairs being reported are determined by selections on the Display Filter pane.
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The RCU Operation pane is updated when the tab is switched from one to another, Refresh is clicked, and settings for the RCU are applied. For the RCU settings operation, see ”RCU operations” on page 54. Figure 22 RCU Operation pane The RCU Operation pane contains the following items: • Switch Display options: • MCU&RCU: Displays the CU Number tree and MCU/RCU list (see ”CU Number tree and MCU/RCU list” on page 48). The MCU/RCU list is displayed by default.
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• CU#: CU number selected on the tree. • Type: MCU or RCU. • S/N and SSID: Serial number and SSID of the other CU of the pair. • Paired CU#: CU number of the other CU of the pair. • M-R Path: Path channel type (Fibre or Serial) between the other CU of the pair. • Status: Normal indicates no failure path between the RCU. Failed indicates there are failure paths between the RCU. This column is blank when the pair CU is MCU. • Num. of Path: Number of paths. This column is blank when the pair CU is MCU.
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The Asynchronous Operation pane is updated when the tab is switched from one to another, Refresh is clicked, and settings are applied. Figure 25 Asynchronous Operation pane The Asynchronous Operation pane contains the following items: • Operation: Current operation performed by the Asynchronous Operation tab. • Pending Update Data Rate: Maximum cache % available for use by Continuous Access XP Async sidefiles. • Offloading Timer (sec): Maximum time between Continuous Access XP Async recordset transfers.
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• CLPR: Number and name of the CLPR to which the volumes forming the pair belong. If the consistency group is not in use, this column is blank. For more information about CLPRs, see the HP StorageWorks XP Disk/Cache Partition user guide. Usage Monitor pane The Usage Monitor pane displays user-selected remote copy I/O statistics and status of remote copy usage monitoring, and provides access to the Continuous Access XP usage monitor operations (see ”Usage Monitor operations” on page 73).
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The History Operations pane is updated when the tab is switched from one to another, Refresh is clicked, and settings are applied. Figure 27 History Operations pane The History Operations pane contains the following items: • Status: Current status of history file. Possible values: • No history file exist: History file does not exist. • Reading a history failed: Failure occurred when referring to history file. • Update history ... n (%): History file update is in progress.
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• VOL: CU number and LDEV number of operated volume. • Paired VOL: CU number and LDEV number of paired volume. • Copy Time: Time taken for operation (from start of operation to end). Displayed only for Pairing Complete and Pair Resync. Complete operations. NOTE: For Continuous Access XP pairs consisting of LUN Expansion (LUSE) volumes, number of Pair Suspend (Failure) rows in the history list does not correspond to number of LDEVs in the LUSE volume.
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To set a disk array as an MCU, configure MCU ports. Configuring MCU ports All Fibre Channel interface ports on the disk array have a default setting of Target port (CHF). Target mode is used for host processor channel interfaces. Fibre Channel ports used for Continuous Access XP communications to RCUs must be configured as Initiator ports. Fibre Channel interface ports in the RCU used to communicate with the MCU must be configured as RCU target ports.
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• Initiator, RCU Target, and Target for fibre • RCP and LCP for serial (see ”Port change operation” on page 65) 4. Click a command. When two or more RCUs are selected in step 2, only the RCU Operation command can be selected. There is no separate pane for the port change operation. Select the port type, and go to the Volume list (go to step 6). 5. Click Set. The pane closes, and the MCU/RCU list changes to the RCU Settings Parameter list.
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• Minimum Paths: Minimum number of paths required for selected RCU connected to the MCU. • Maximum Initial Copy Activity: Number of concurrent initial copy operations. • RIO MIH Time: Time value for the remote I/O (RIO) missing interrupt handler (MIH), which is the wait time until data transfer from the MCU to RCU is complete. • Path Blockade Watch: Time for monitoring blockade in the Fibre Channel paths on the MCU side. • RCU Registered: Date and time the RCU was registered.
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NOTE: If four RCUs (maximum number of RCUs you can register) are already registered, you cannot select Add RCU. Figure 29 Add RCU pane • RCU S/N: Serial number of RCU being registered. S/N is five digits. • Controller ID: Controller ID of RCU being registered. • Logical Adr. (RCU CU#): CU number of RCU being registered. CU number is 0-1F. • Path Gr.ID: Used to enter the path group ID for using CU Free.
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• Cancel button: Cancels settings made on the Add RCU pane, and closes the pane. Figure 30 RCU Option pane Use the RCU Option pane to set the options for the RCU. • Minimum Paths: Minimum number of paths required for each RCU connected to the current MCU. The default is one. If you specify a number that is larger than the number of paths set on the Register RCU pane or the number of paths falls below this number (for example, failed path), an error occurs.
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Registering RCUs to the connected MCU 1. Ensure that remote copy connections and MCU ports are properly configured. Get the S/N of the RCU and the SSIDs for the CU image in the RCU. The register RCU operation fails without this information. The disk array should have a label or tag indicating its S/N and SSIDs. The HP representative can also get the RCU S/N and SSIDs using the RCU’s service processor (at the remote site). 2. In the RCU Operation pane, click MCU&RCU in the Switch Display box. 3.
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• Min.Path: Minimum number of paths required for each RCU connected to the current MCU • Activity: Number of concurrent initial copy operations • MIH Time: Time value for the remote I/O (RIO) missing interrupt handler (MIH) • Path Watch: Time for monitoring blockade in the Fibre Channel paths on the MCU side Modifying RCU options (Change RCU Option) Use the RCU Options pane to modify RCU options set when you registered the RCU.
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• MIH Time: Time value for the remote I/O (RIO) missing interrupt handler (MIH) • Path Watch: Time for monitoring blockade in the Fibre Channel paths on the MCU side Deleting RCUs (Delete RCU) You can delete an RCU from an MCU only after all Continuous Access XP volume pairs between the MCU CU image and RCU CU image are deleted. When you delete an RCU from an MCU, the MCU deletes all logical paths from the current MCU CU image to the selected RCU CU image.
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Figure 35 Add RCU pane used for configuration in Figure 34 Adding and deleting logical paths for RCUs (Add Path/Delete Path) Use the Add Path and Delete Path commands to add and delete paths for an RCU. When the Add Path command is selected, the Add Path pane appears. Figure 36 Add Path pane The MCU-RCU Path field includes: • MCU Port: MCU port number. The Initiator and RCP are listed in the drop-down list and can be selected. • RCU Port: RCU port number. The RCU Target port must be specified.
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NOTE: You can select the port number from the drop-down list, or enter it directly. When you enter the port number directly, you can specify it with two characters (for example, enter 1A for CL1-A). You can also enter the port number in both lowercase and uppercase characters. The Cancel button cancels settings made. The Set button applies settings made and changes the list. NOTE: Maximum number of paths is eight. Each item has seven fields to enter paths, but you cannot enter more than eight paths.
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Adding and deleting SSIDs for RCUs (Add SSID/Delete SSID) Before adding an SSID, ensure that the remote copy connection is properly installed. You can add three SSIDs to each RCU. Before deleting an SSID, ensure that the remaining SSIDs are valid, or the connection between the MCU and RCU may be lost. Use the Add SSID and Delete SSID commands to add and delete SSIDs for an existing RCU. When the Add SSID command is selected, the Add SSID pane appears.
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Port change operation Use the RCU Operation tab to change the port mode. Clicking Port in the Switch Display box changes the tree to the Port tree and changes the list to the Port list. Use the Port tree and Port list to change the port type. Figure 38 Changing port types 1. Click Port in the Switch Display box to change the tree to the Port tree and change the list to the Port list. 2. Click a port or a port type from the Port tree. Only the selected port or port type is displayed in the Port list. 3.
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Modifying parameters and deleting settings After RCU, Path, and SSID operations, parameters can be modified individually. Also the RCUs, Paths, and/or SSIDs set by each operation can be deleted. Modifying parameters 1. Click the RCU, Path, or SSID on the list. 2. Right-click, and click Modify. A pane for each operation appears. 3. Modify parameters, and click Set. 4. Click Apply on the Continuous Access XP main pane to apply modifications.
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NOTE: After being set, options can be modified and canceled (see ”Modifying parameters and deleting consistency groups” on page 72). 6. Click Apply on the Continuous Access XP main pane to apply settings to the disk array. Viewing consistency group status (CT Group Status) Use the CT Group Status command to display consistency group status information. 1. From the Consistency Group tree, click a consistency group mode that includes the consistency group you want to display. 2.
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Adding consistency groups (Add CT Group) Use the Add CT Group command to add a consistency group to the connected MCU. When the Add CT Group command is selected, the Add CT Group pane appears. Use the Add CT Group pane to select group options for the group. Figure 40 Add CT Group pane • MCU-RCU Path: Path type for remote copy connections. • Time Out (Copy Pending) (min.
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NOTE: After being set, options can be modified and canceled (see ”Modifying parameters and deleting consistency groups” on page 72). 8. Click Apply on the Continuous Access XP main pane to apply settings to the disk array. When the Add CT Group pane closes, the list changes to the Consistency Group Settings Parameter list. However, columns other than CTG are blank.
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4. From the Consistency Group list, click the consistency groups to be modified. Select more than one consistency group with MCU in the This CU column. 5. Right-click, click CT Group Operation, and click CT Group Option. The CT Group Option pane appears. If the CT Group Option command is not enabled, split the remaining pairs in this consistency group. 6. Change group options as needed. 7. Click Set in the CT Group Option pane.
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array. Async options apply to the entire physical control unit, including all Continuous Access XP P-VOLs and S-VOLs behind the control unit. Figure 43 Async Option pane All default settings indicate the current settings. • Pending Update Data Rate (%): Continuous Access XP Asynchronous sidefile threshold, which is maximum amount of cache that can be used for storing Continuous Access XP Async recordsets (sidefiles).
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NOTE: Specify a value not exceeding the I/O Delay Increase for the I/O Delay Start. Specify a value not exceeding the Pending Update Data Rate for the I/O Delay Increase. If sidefile threshold is set between 0 to 30%, influence to the I/O delay is kept low. HP recommends that you change the I/O Delay Start and I/O Delay Increase when all Continuous Access XP asynchronous pairs are suspended, or host I/O and sidefiles do not exist.
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For the CT Group operation, the Cancel All command deletes all consistency groups on the list, and all consistency groups are removed from operations. All consistency groups can also be deleted using the Delete command and selecting all consistency groups on the list. When all consistency groups are deleted (by the Cancel All or Delete command), the list status becomes the Volume list. For the Asynchronous Option operation, the Delete command is not available.
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3. Right-click the graph area, and click Display Item. The Display Item pane appears. Figure 45 Display Item pane 4. To display I/O statistics for all LDEVs in the subsystem, click Subsystem Total. To display I/O statistics for a specific LU, click LU, and enter the LU by selecting the port from the drop-down list and entering the group (00-7F) and LUN (00-FF). NOTE: CU:LDEV is displayed on the top of the graph. If # is added to the end of the LDEV number, such as 00:3C#, the LDEV is an external volume.
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• To stop displaying all graphs, click Close All. Table 17 Remote copy I/O statistics Statistic Description RIO count All RIO count Total number of remote I/Os. All read count Total number of remote read I/Os. All write count Total number of remote write I/Os. Initial copy Initial copy RIO count Number of initial copy remote I/Os. Initial copy hit count Number of initial copy hits. Average transfer rate (kB/s) Average transfer rate (kB/sec) for initial copy remote I/Os.
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• Stopping the usage monitoring function by clicking Stop in the Operation drop-down list, and clicking Apply. • Clicking another tab. • Exiting Command View XP or XP Remote Web Console. Optimizing Continuous Access XP operations and disk array performance Continuous Access XP operations result in increased utilization of the disk array’s channel resources because of additional write (remote copy) operations to secondary volumes.
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Table 18 Disk array performance conditions and recommendations (continued) Condition Description Recommendations Sequential write operations Continuous Access XP operations can Avoid performing restore operations to volumes belonging to Continuous Access XP pairs. Instead, restore data to a scratch volume and then create the Continuous Access XP volume pair. Cache size Large cache size improves read hit performance, which allows more disk array resources to be devoted to write operations.
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5. For Fibre Channel interface, reset initiator ports to ordinary targets at MCUs (see ”Port change operation” on page 65). Performing Continuous Access XP pair operations Preparing for Continuous Access XP volume pair operations Before starting Continuous Access XP operations, consider the relative importance of disk array I/O performance and disaster recovery preparation.
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• Pairdisplay: Displays LU status (see ”Viewing Continuous Access XP pair status for LUs and LDEVs (Pairdisplay)” on page 80). • Paircreate: Creates a volume pair using the Synchronous and Asynchronous commands (see ”Creating Continuous Access XP volume pairs (Paircreate)” on page 81). • Pairsplit-S: Deletes pairs (see ”Deleting Continuous Access XP volume pairs (Pairsplit-S)” on page 90). • Pairsplit-r: Splits (Suspends) pairs (see ”Splitting Continuous Access XP pairs (Pairsplit-r)” on page 85).
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The Cancel All command deletes all LUs listed on the Pair Settings Parameter list, and all LUs are removed from pair settings operations. LUs can also be deleted using the Omit command and selecting all LUs on the Pair Settings Parameter list. When all LUs are deleted (by the Cancel All or Omit command), the list status becomes the Volume list. Viewing Continuous Access XP pair status for LUs and LDEVs (Pairdisplay) The Pairdisplay command displays detailed Continuous Access XP pair status information. 1.
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• P-VOL Fence Level: Conditions under which the MCU rejects write operations to the P-VOL. • Never: Never fence the operation • Data: Fence when the MCU cannot successfully execute an update copy operation for any reason • Status: Fence only if the MCU cannot change the S-VOL status to the same status as the P-VOL. • S-VOL Write: Enabled or disabled for this pair (enabled only when pair is split). • Pair Established: Date and time volume pair was created.
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• P-VOL: Port - Group - LUN of the primary volume (P-VOL), CLPR number, and CLPR name. NOTE: If # is added to the end of the LDEV number, such as 00:3C#, the LDEV is an external volume. For details about external volumes, see the HP StorageWorks External Storage XP user guide. • S-VOL: Secondary volume (S-VOL). Specify each item as follows: Port: 1A-2R, Group: 00-7F, LUN: 00-FF. If you select two or more LUs as P-VOLs in the Volume list, select an S-VOL for the P-VOL of the lowest LUN.
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2. Connect to the disk array containing P-VOLs of the pairs you are creating, and start Continuous Access XP. RCPs or Initiator ports must be configured (see ”Configuring MCU ports” on page 54), and RCUs must be already registered (see ”Registering RCUs (Add RCU)” on page 56). 3. From the Volume list on the Continuous Access XP main pane, click the LUs that will be P-VOLs of the Continuous Access XP volume pairs.
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• Type: Synchronous or Asynchronous of the pair created. • Mode: Entire: Copy all cylinders. No Copy: Do not copy. • Fence: Conditions under which the MCU rejects write operations to the P-VOL: Never, Data, or Status. • Pace: Number of tracks (1-15) for initial copy. • Priority: Priority (scheduling order) of initial copy operations. • Diff: In the measurement of the Cylinder or the Track, Continuous Access XP manages differentials among data.
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For example, suppose the maximum initial copy activity setting is four, and you add six Continuous Access XP pairs at one time (for LUNs 00 through 05) with the initial copy priority set as follows: P-VOL of pair Priority LUN 03 1 LUN 05 2 LUN 00 3 LUN 04 4 LUN 01, 02 5 The MCU starts initial copy operations for LUNs 03, 05, 00, and 04 immediately, starts LUN 01 when one of the first four initial copy operations is complete, and starts LUN 02 when the next initial copy operation is complete.
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information about split Continuous Access XP pairs, see ”Continuous Access XP split types (PSUS)” on page 27. Figure 49 Pairsplit-r pane • Volume: Port - Host group - LUN of the selected volume. NOTE: If # is added to the end of the LDEV number, such as 00:3C#, the LDEV is an external volume. For details about external volumes, see the HP StorageWorks External Storage XP user guide. • S-VOL Write: Default is Disable.
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• Pending Update: Drain: The MCU changes the Continuous Access XP Async pair status from Suspending to PSUS only after the RCU accepts the pairsplit operation and completes the following steps: (a) Finishes settling all pending recordsets for the pair. (b) Completes negotiation with all MCUs (report ready-for-suspension to all MCUs and receive acknowledgements) without further recordsets generated.
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When the Pairsplit-r pane closes, the list changes to the Pair Settings Parameter list (Pairsplit-r). Figure 50 Pair Settings Parameter list (Pairsplit-r) The Pair Settings Parameter list (Pairsplit-r) displays the following information for selected pairs: • Port, Group (TID), and LUN of the LU in the connected disk array. • S/N and SSID of the RCU (MCU if connected to the RCU). • S-VOL Wrt: Disable or enable. Enable means the S-VOL is available to receive read and write I/Os.
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• P-VOL: Port - Host group - LUN of the selected volume. NOTE: If # is added to the end of the LDEV number, such as 00:3C#, the LDEV is an external volume. For details about external volumes, see the HP StorageWorks External Storage XP user guide. • P-VOL Fence Level: Fence level. • Never: Never fence the operation. • Data: Fence when the MCU cannot successfully execute an update copy operation for any reason. • Status: Fence only if the MCU cannot change the S-VOL status to the same status as the P-VOL.
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NOTE: After being set, options can be modified and canceled (see ”Modifying parameters and deleting LUs” on page 79). NOTE: To resync all split/suspended Continuous Access XP Async pairs in a consistency group, ensure that the Resume range option on the Pairresync pane is set to Group. 7. To execute pairresync requests quickly, select the Use Time-Saving Mode check box above the Pair Settings Parameter list (Pairresync). 8. Click Apply on the Continuous Access XP main pane to resync specified pairs. 9.
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Delete a Continuous Access XP pair from the RCU only for disaster recovery (see ”Continuous Access XP disaster recovery operations” on page 97). When a Continuous Access XP pair is deleted from the RCU, the RCU changes the S-VOL pair status to SMPL, but does not change the pair status of the corresponding P-VOL. When the MCU performs the next Continuous Access XP operation, the MCU detects that the S-VOL status changed, and changes the P-VOL status to PSUS-pairsplit-S to RCU.
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CAUTION: Do not use this option when deleting pairs at the RCU during disaster recovery. This option is available only when one pair is selected. • C/T (RCU only): The RCU deletes all Continuous Access XP Async pairs with the same consistency time. • LU (MCU or RCU): The MCU and RCU deletes only the specified Continuous Access XP Async pairs. Use this option to remove individual volumes from consistency groups.
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When the Pairsplit-S pane closes, the list changes to the Pair Settings Parameter list (Pairsplit-S). Figure 54 Pair Settings Parameter list (Pairsplit-S) • Port, Group, and LUN of the selected LU number. • S/N and SSID of the RCU (MCU if connected to the RCU). • Mode: Yes (delete forcibly) or No (delete normally). • Range: Range for deleting the asynchronous pair: Group, LU, or C/T.
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2. From the CU Number/Port Number tree on the Continuous Access XP main pane, click the number of the correct CU image. 3. From the Volume list, click the Continuous Access XP volume pairs to be modified. Select either Continuous Access XP Sync or Async pairs, but not both. 4. Right-click, and click Change Pair Option. The Change Pair Option pane appears. 5. Click the pair options for selected pairs, and click Set to close the Change Pair Option pane and set parameters.
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2. Connect to the disk array containing volumes to be migrated, and start Continuous Access XP. If not already done, install remote copy connections and configure ports (initiator ports for fibre, RCPs for serial) if migrating between disk arrays, and register RCUs. 3.
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If power is removed from an RCU or remote copy connection while Continuous Access XP operations are in progress, the MCU detects the communications failure, suspends all affected pairs, and generates SIMs reporting the failures. The MCU changes the status of P-VOLs to suspended-by RCU, but cannot change the status of S-VOLs. If an MCU or RCU is powered off and its backup batteries are fully discharged while Continuous Access XP pairs are suspended, the P-VOL and S-VOL cylinder maps are not retained.
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Continuous Access XP disaster recovery operations Preparing for disaster recovery The type of disaster and status of Continuous Access XP volume pairs determines the best approach for disaster recovery. For example, if all Continuous Access XP volume pairs are in the PAIR state when a total system failure occurs at a single point in time, S-VOLs are current and recovery is straightforward.
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NOTE: The P-VOL fence-level setting does not apply to Continuous Access XP Asynchronous pairs. Continuous Access XP Async P-VOLs are never fenced due to suspension of the pair. Table 19 Fence-level settings on Continuous Access XP Sync P-VOLs Type of failure Fence-level setting S-VOL Data S-VOL Status Never Update copy operation failed, and the MCU changed the status of the S-VOL to PSUE.
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by means of multiplication can function with the Data fence-level setting. For example, Oracle multiplies the Redo log file by itself (default = three times). Figure 57 Relationship between log file and data file in PAIR status Because most UNIX file systems (excluding JFS and VxFS) have no journal files, the P-VOL fence level should be defined as Never.
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Switching operations to remote sites If a disaster or failure occurs at the primary site, the first disaster recovery activity is to switch operations to the secondary site. Continuous Access XP Synchronous S-VOLs are recovered individually based on the pair status and P-VOL fence-level information for each pair. Continuous Access XP Async S-VOLs are recovered based on pair status and consistency status (at the RCU). Basic procedures for switching operations to the remote backup site are: 1.
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Table 20 Determining Continuous Access XP Synchronous S-VOL currency based on its pair status and P-VOL fence-level setting (continued) Status of S-VOL Fence level Currency of S-VOL PAIR Data Status Current. This S-VOL is synchronized with its P-VOL. Never Needs to be analyzed. This S-VOL requires further analysis to determine its level of currency. PSUE initial copy failed Data Status Never Inconsistent. This S-VOL is not synchronized because not all cylinders have been copied from the P-VOL yet.
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Table 21 Determining Continuous Access XP Async S-VOL consistency based on its pair status and consistency status (continued) Status of S-VOL Usable for Recovery? Description PSUE-Group Yes Update sequence consistency across these S-VOLs is ensured at the point in time indicated by the consistency time. These S-VOLs can be used for disaster recovery at the secondary system. Updates performed at the primary system after the indicated consistency time were probably lost.
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3. Split (pairsplit-r) all Continuous Access XP pairs at MCUs (original RCUs) to destage any pending data from cache. Confirm that pairs are split (PSUS) before proceeding. If an error occurs, resolve it before proceeding. 4. Delete all Continuous Access XP pairs at MCUs (original RCUs). You do not need to use the Delete Pair by Force option. For Continuous Access XP Async pairs, the MCU and RCU complete all pending updates before changing the pair status to SMPL. 5.
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NOTE: If you delete the Continuous Access XP Asynchronous volume pair, delete only the pair containing the volume with the pinned track. To do this, select LU for Asynchronous Parameters, and click Delete Range. 3. If the volume is offline (for example, S-VOL has a pinned track), vary the volume online. 4. Perform your usual procedure for recovering data from a pinned track.
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Index A Add CT Group pane 68 Async Option 70 Asynchronous Operation pane 49 audience, documentation 9 B BC, combining with Continuous Access XP 39 C cache inflow control 22 requirements 32 size 77 Cache LUN, combining with Continuous Access XP 39 Change Pair Option command 93 Command View XP management station 18 components 14 configuration operations 53 consistency groups adding 68 defined 16 deleting 70, 72 options 23, 69 parameters, modifying 72 requirements 32 consistency status, Continuous Access XP
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E M error codes 103 ESCON connections components for 15 configuring 37 distances supported 17 requirements 35 system requirements 31 failover, host 18, 99 fence level 84, 97 Fibre Channel ports components for 14 configuring 37 direct connection 34 distances supported 17, 34 extender connection 35 initiator 17 RCU path parameters 61 switch connection 35 system requirements 30 fibre remote copy connections 34 file recovery 99 firmware versions 9 functions 42 main pane 42, 43 MCUs configuring 37 consistency
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Pairdisplay command 80 Pairresync command 88 Pairsplit-r command 85 Pairsplit-r options 86 Pairsplit-S command 90 panes 42 PDUB 25, 26, 31, 45 pinned tracks 103 Point-in-Time (PiT) copies 95 Port list 49 Port tree 49 ports initiator 17, 54 local (LCPs) 18 prioritized 39 remote control (RCPs) 18 system requirements 30 target 18, 54 tree and list 49 powering off components 95 prerequisites 9 Prioritized Port Control 39 PSUE pair status 25, 26 status icons 45 suspend types 29 S-VOL currency 101 PSUEGroup 102 P
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SMPL Continuous Access XP pair status 25 pair status 25, 45 Pairsplit-S command 90 S-VOL consistency 101 S-VOL currency 100 Snapshot function 46 SNMP trap 103 split types 27 splitting with pairsplit-r command 85 SSIDs, adding/deleting for RCUs 64 starting Continuous Access XP 41 statistics, Usage Monitor 73 status icons 44 status, RCU 55 Subscriber’s choice, HP 10 Suspending status 45 S-VOLs Change Pair Option command 93 consistency status 28 consistency, analyzing 101 copying using Continuous Access XP Asy