HP-UX 11i v3 Mass Storage Device Naming

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Abstract.............................................................................................................................................. 2

Terms and Definitions........................................................................................................................... 2

Introduction......................................................................................................................................... 3

Persistent Device Special File (DSF) Naming Scheme................................................................................ 4

Disk device file naming convention..................................................................................................... 4

Tape device special file naming convention......................................................................................... 5

Auto-changer and Library robotic device special file naming convention................................................. 5

Array controller and other device file naming convention...................................................................... 6

Creating device special files manually................................................................................................ 6

Displaying options associated with a device special file ....................................................................... 8

The agile addressing hardware path format............................................................................................ 9

LUN hardware path format ............................................................................................................... 9

Lunpath hardware path format........................................................................................................... 9

Mapping between agile addressing scheme and legacy scheme............................................................. 10

Mapping between legacy DSFs and persistent DSFs........................................................................... 10

Mapping between legacy hardware paths and agile addressing hardware paths.................................. 11

Mapping between LUNs and LUN paths........................................................................................... 12

Additional Resources.......................................................................................................................... 13

Summary of content (13 pages)

PAGE 1
HP-UX 11i v3 Mass Storage Device Naming Abstract.............................................................................................................................................. 2 Terms and Definitions ........................................................................................................................... 2 Introduction.........................................................................................................................................
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Abstract This paper describes the HP-UX 11i v3 mass storage device naming. It is intended for system administrators and other users of the HP-UX mass storage subsystem. The reader is assumed to have a basic knowledge of the mass storage device naming on HP-UX releases prior to HP-UX 11i v3. HP-UX 11i v3 introduces a new agile naming scheme for mass storage devices, which addresses the limitations of the device naming scheme used in previous releases of HP-UX 11i.
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legacy naming model / legacy format Device special file format convention used prior to HP-UX 11i v3. This model is maintained in HP-UX 11i v3 for backward compatibility purpose. (legacy) DSF A path dependent device file, following the legacy naming model conventions, wherein the DSF embeds the bus/target/lun/option for a specific path to a mass storage device (Ex. /dev/dsk/c#t#d#). SCSI class driver A HP-UX device driver which manages one or more specific classes of mass storage devices.
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• It enables certain re-configurations of the host system and the storage area network (SAN), without affecting the representation of the device on the host system. This includes operations such as connecting the device through a different HBA on the host, and moving the device to a different switch or hub in the SAN. Persistent Device Special File (DSF) Naming Scheme The persistent DSF is a path independent and persistent 1 representation of a Logical Unit (LUN).
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Where disk_partition_number is the number assigned to the disk partition by the system if the disk is formatted into several logical partitions. The following table shows examples of disk device special files created for two disks with instance numbers 0 and 100 respectively. The disk with the instance number 0 has two partitions.
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For example if the system discovers 2 auto-changer devices and assigns them instance numbers 0 and 1 respectively, it will automatically create the following device files: /dev/rchgr/autoch0 and /dev/rchgr/autoch1. Array controller and other device file naming convention Any device which is not claimed by a class driver is bound by default to the pass-through driver: esctl. This is the case for array controller devices.
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# insf -C disk • To re-install all default device files for all devices bound to the estape driver: # insf -d estape -e insf: Installing special files for estape instance 2 address 64000/0xfa00/0x5 insf: Installing special files for estape instance 3 address 64000/0xfa00/0x10 Note: When no DSF is created, insf does not display any message. That is the case for instance if insf is run without the -e option and there is no new device on the system.
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Creating pass-through device files using mksf In some situations the user may need to send SCSI commands directly to the device via the passthrough driver: esctl. For that purpose the user should create a device file attached to the pass-through driver. In HP-UX releases prior to 11i v3, mknod was used to create pass-through device files. In HPUX 11i v3 the –P option of mksf must be used to create pass-through persistent DSFs.
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The Agile Addressing Hardware Path Format The agile addressing scheme defines two new sets of hardware paths for each device: • The LUN hardware path: is a virtualized path, which represents the LUN independently of any of its I/O paths. • A set of lunpath hardware paths: each represents a specific I/O path to the LUN and maps to a single legacy hardware path. The format of the lunpath hardware path is different from the legacy hardware path and depends on the SCSI transport.
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Notes: • The lunpath represents an I/O path to a LUN. In the agile view of the I/O tree, it is an independent SCSI object of the class ‘lunpath’, and bound to the pseudo-driver eslpt. • Likewise the target path is an independent object in the agile view of the I/O tree. It is of class ‘tgtpath’ and is bound to the pseudo-driver estp. The following output of the ioscan command shows examples of lunpath hardware paths.
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# ioscan -m dsf /dev/disk/disk19 Persistent DSF Legacy DSF(s) ======================================== /dev/disk/disk19 /dev/dsk/c4t1d0 /dev/dsk/c5t1d0 • To view the persistent DSF corresponding to a legacy DSF (Note: A legacy DSF always maps to a single persistent DSF) o ioscan -m dsf # ioscan -m dsf /dev/dsk/c4t1d0 Persistent DSF Legacy DSF(s) ======================================== /dev/disk/disk19 • /dev/dsk/c4t1d0 To view mappings of all existing mass storage DSFs: o ioscan -
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o ioscan -m hwpath -H # ioscan -m hwpath -H 0/3/1/0.0x21000020371972ee.0x0 Lun H/W Path Lunpath H/W Path Legacy H/W Path ==================================================================== 64000/0xfa00/0x3 0/3/1/0.0x21000020371972ee.0x0 • 0/3/1/0.8.0.255.0.0.0 To view the LUN hardware path, and the lunpath hardware path corresponding to a legacy hardware path o ioscan -m hwpath -H # ioscan -m hwpath -H 0/3/1/0.8.0.255.0.0.
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# ioscan -m lun /dev/rdisk/disk20 Class I Lun H/W Path Driver S/W State H/W Type Health Description ====================================================================== disk 20 64000/0xfa00/0x5 esdisk CLAIMED DEVICE online SEAGATE ST39103FC 0/3/1/0.0x21000020371972eb.0x0 0/4/1/0.0x21000020371972eb.0x0 /dev/disk/disk20 /dev/rdisk/disk20 Additional Resources White papers White papers can be found at: http://docs.hp.com/en/netsys.