Help
Table Of Contents
- Dell EMC Storage Systems Online Help for the metro node appliance
- Contents
- Figures
- Welcome
- Using the GUI
- Configuring GUI default settings
- Using storage hierarchy maps
- Viewing system status
- Monitoring the system
- Performance
- The Performance Monitoring dashboard
- Viewing a chart
- Modifying a dashboard layout
- Creating a custom dashboard
- Removing a chart
- Moving a chart
- Back-end Bandwidth Chart
- Back-end Throughput chart
- Back-end Errors chart
- Back-end Latency chart
- CPU utilization chart
- Heap Usage chart
- Front-end Queue Depth chart
- Front-end Bandwidth chart
- Front-end Latency chart
- Front-end Throughput chart
- Front-end Aborts chart
- Write Latency Delta chart
- WAN Port Performance chart
- WAN Latency chart
- Rebuild Status dashboard
- Virtual Volumes dashboard
- Front End Ports dashboard
- System Health
- Performance
- Provisioning storage
- Guide
- Provisioning from storage volumes
- Provision Job properties
- Distributed storage
- Storage arrays
- Storage volumes
- Devices
- About devices
- Using the Devices view
- The Create Devices wizard
- The Add Local/Remote Mirror wizards
- Viewing the status of IO to a device
- Creating a device
- Renaming a device
- Deleting a device
- Mirroring a device
- Device status
- Device component properties
- Device properties
- Distributed device properties
- Add capacity to virtual volumes
- Extent properties
- Extents
- Distributed devices
- About distributed devices
- The Distributed Devices view
- The Create Distributed Device from Claimed Storage Volumes wizard
- Distributed device rule sets
- Changing the rule set for a distributed device
- Creating a distributed device
- Deleting a distributed device
- Renaming a distributed device
- Distributed Device status
- Virtual volumes
- About virtual volumes
- The Virtual Volumes view
- The Distributed Virtual Volumes view
- Creating a virtual volume
- About virtual volume expansion
- Expanding a virtual volume using storage volumes
- Enabling or disabling remote access for a volume
- Manually assigning LUN numbers to volumes
- Deleting a volume
- Renaming a volume
- Tearing down a volume
- Virtual Volume status
- Pool properties
- Virtual volume properties
- Show ITLs dialog box
- Logical unit properties
- ALUA Support field values
- Visibility field values
- Extent or Device mobility job properties
- Metro node port properties
- Storage array properties
- Storage view properties
- Storage volume properties
- Create Virtual Volumes dialog box
- Consistency group
- About consistency groups
- Using the Consistency Groups view
- Distributed Consistency Groups view
- Create Consistency Group wizard
- Types of consistency groups
- Creating a consistency group
- Adding a volume to a consistency group
- Removing a volume from a consistency group
- Deleting a consistency group
- Consistency Group status
- Consistency group properties
- Step 1: Select or create a consistency group for the virtual volume
- Step 1: Create a consistency group
- Step 2: Select volume options
- Step 3: Select a storage pool
- Step 3: Select a pool for each mirror on the second cluster
- Step 3: Select a pool for each mirror in the cluster
- Step3: Create thin virtual volumes
- Select a storage view for the virtual volume(s) (optional)
- Step 5: Review your selections
- Step 6: View results
- Step 2: Select volume options
- Step 2: Select volume options
- Step 3: Select a storage volume to create the virtual volume
- Step 3: Select a source and target storage volume
- Step 3: Create thin volumes
- Step 3: Select a target storage volume on the remote cluster
- Step 3: Select target storage on the remote cluster
- Step 6: View results
- Show Logical Units
- Exporting storage
- Initiators and metro node ports
- Storage views
- About storage views
- Using the Storage Views screen
- The Create Storage View wizard
- Creating a storage view
- Deleting a storage view
- Renaming a storage view
- Adding or removing initiators from a storage view
- Adding virtual volumes to a storage view
- Removing virtual volumes from a storage view
- Adding or removing metro node ports from a storage view
- Storage view status
- Storage group properties
- Director properties
- Cluster properties
- Moving data
- Mobility
- Move Data Within Cluster
- Move Data Across Clusters
- Create Mobility Job wizards
- Mobility job transfer size
- Creating a mobility job
- Viewing job details
- Committing a job
- Canceling a job
- Pausing a job
- Resuming a job
- Removing the record of a job
- Changing a job transfer size
- Searching for a job
- Mobility job status
- Notifications
● In a metro node Metro you will incur extra WAN round-trip time on your write latency since writes need to be successfully
written to both cluster's storage before the host is acknowledged. This extra latency may impact the throughput and IOPS
of serialized-type applications.
Corrective actions
● Check for bandwidth/IOPS over-provisioned metro node front-end ports. Be sure to balance hosts and LUNs across
the available directors and front-end ports presented from metro node. Check the front-end fabric for saturation or over-
capacity.
● Check CPU utilization. If unusually busy, metro node will be limited in the amount of bandwidth it can provide.
● Check back-end latency. If on average the back-end latency is large, or there are large spikes, there could be a poorly
performing back-end fabric or an unhealthy, un-optimized, or over-loaded storage array. Perform a back-end fabric analysis
and a performance analysis of all storage arrays in question.
● Check front-end aborts. Their presence indicate that metro node is taking too long to respond to the host. These might
indicate problems with the front-end fabric or slow SCSI reservations.
● Check back-end errors. If the metro node back-end is required to retry an operation because of errors, then this will add to
the delay in completing the operation to the host.
● Check front-end operations count (queue depth). If this counter is large, this may explain larger than normal front-end
latency.
● Check for high metro node write delta time. Refer to the Corrective actions section in the Write Latency Delta chart topic.
● Check the front-end average iosize. For writes, iosizes larger than 128KB become serialized into 128KB requests. This can
extend the time to complete large block transfers, or in extreme examples, cause the operation to timeout and fail.
● Verify that front-end Fibre Channel ports, HBAs and switch ports are configured to the correct port speeds.
● Configure your host multipathing software based on metro node best practices, and ensure the installed software versions
are compatible with metro node. For more information on compatibility, refer to the Simple Support Matrix for metro node
document, available on EMC Online Support and in the SolVe Desktop.
For metro node Metro configurations
● Check the health of the inter-cluster link and maximum performance capabilities. From the GUI, check the inter-cluster WAN
bandwidth. If your application throughput appears low and is similar to what the WAN bandwidth reports, then you are
probably limited by the WAN. In this case:
○ Make sure you have provisioned enough inter-cluster bandwidth for the desired application workload. Verify that
your WAN configuration is supported by metro node (minimum supported bandwidth, supported inter-cluster latency,
compatible WAN hardware and software).
○ For Metro-FC, if the inter-cluster WAN is over a FC fabric, confirm that you have allocated enough buffer credits or
configured the FC WAN ports properly on your switches. Check for buffer credit starvation, c3 discards, and CRC errors.
Some vendors may require extended fabric licenses to enable WAN features.
○ Validate your WAN performance before going live in production. Create multiple test distributed devices and force them
to rebuild. Observe the performance of the rebuilds.
● When troubleshooting distributed device performance, if feasible, check local device performance. Export a test LUN from
your storage array to metro node, then to the host, and run a test I/O workload.
● Check for any unexpected local or distributed rebuilds or data migrations. There will be some performance impact to host
application traffic that relies on the same virtual volumes and storage volumes. Tune the rebuild transfer-size setting to limit
the performance impact of rebuild and migrations. Consider scheduling migrations during off-peak hours.
Changing the view
To view the bandwidth of a single director in your metro node system, select the director name from the Director drop-down.
Viewing the Virtual Volume Bandwidth chart
1. From the GUI main menu, click Performance.
2. Click + and select Add Virtual Volumes Dashboard.
Monitoring the system
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