I/O: Allocation Notes

When planning or performing I/O allocation, note the following:

Mass Storage Stack Formats The agile view of mass storage introduced in HP-UX 11i v3 (11.31) is supported with vPars. However, the lunpath hardware path format and lun hardware path format are not supported for use on the vPars command line, and are not printed by any vPars commands. You must continue to use the legacy hardware path format that existed in previous vPars releases when using the vPars commands; for HP-UX 11i v3 (11.31), ioscan’s default output will continue to show the legacy format.
However, wherever the new formats are supported by other 11.31 HP-UX commands and tools, you can use these new formats within the virtual partitions running 11.31. For information on using the new mass storage stack formats, multipathing, and agile addressing, see the white paper The Next Generation Mass Storage Stack and the manual HP-UX System Administrator's Guide: Overview.
When using HP-UX commands in the agile view to affect boot paths, such as with the setboot command, vPars requires a corresponding legacy hardware path to exist. When planning your system configuration you should be aware that there will be no legacy hardware paths in the following cases, due to limitations in the minor number format of legacy device special files:
- you have more than 255 I/O busses
- you have more than 32,768 LUNs. Note that for the first release of 11.31, only up to 16,384 LUNs are supported and for 11.23, only up to 8192 LUNs are supported.
An LBA can be assigned to at most one virtual partition at any given time. When you are planning your I/O to virtual partition assignments, note that only one virtual partition may own any hardware at or below the LBA (Local Bus Adapter) level. In other words, hardware at or below the LBA level must be in the same virtual partition.
Example Looking at the ioscan output of a rp7400/N4000, the two internal disk slots use the same LBA:
0/0 ba Local PCI Bus Adapter (782) 0/0/2/0 ext_bus SCSI C875 Ultra Wide Single-Ended 0/0/2/1 ext_bus SCSI C875 Ultra Wide Single-Ended
Therefore, you cannot assign one of the internal disks to partition vpar1 and the other internal disk to partition vpar2; these disks must reside in the same partition.

Syntax Notes When specifying only the SBA on the command-line, the vPars commands will assume the change applies to all LBAs under the specified SBA.

The exception are boot disks; boot disks are specified using the full legacy hardware path.




	NOTE: When assigning I/O, if you specify a path below the LBA level (for example, `cell/sba/lba/.../device`, vPars automatically assigns the LBA to the virtual partition. For example, if you specify `-a io:0/0/0/2/0.6.0` where `0/0/0` is the cell/sba/lba, the lba of 0/0/0 is assigned to the virtual partition. Further, this LBA assignment implies that all devices using `0/0/0` are assigned to the virtual partition. The assignment rules of LBAs remain applicable: the LBA can only be owned by one virtual partition. For example, once the LBA at 0/0/0 is assigned to one virtual partition, it cannot be simultaneously assigned to any other virtual partition. Thus, if the device at `0/0/0/2/0.6.0` is assigned to a virtual partition, the LBA at 0/0/0 is assigned to that virtual partition, so the device at `0/0/0/3/0.6.0` cannot be assigned to a different virtual partition.

LBA Example

The vparcreate command on a non-nPartitionable system looks like:

#vparcreate -p vpar1 -a cpu::1 -a cpu:::1 -a mem::1024 -a io:0.0 -a io:0.0.2.0.6.0:BOOT

where the I/O assignment is specified using the LBA level (-a io:0.0) and the boot disk is specified using the full hardware path (-a io:0.0.2.0.6.0).

For an nPartitionable system, the vparcreate command would look like:

# vparcreate -p vpar1 -a cpu::1 -a cpu:::1 -a mem::1024 -a io:0.0.0 \
-a io:0.0.0.2.0.6.0:BOOT

where the I/O assignment is specified using the LBA level (-a io:0.0.0.) and the boot disk is specified using the full hardware path (-a io:0.0.0.2.0.6.0).

For information on using the LBA level on nPartitionable systems, also see “Planning, Installing, and Using vPars with an nPartitionable Server”.

SBA/LBA versus cell/SBA/LBA When viewing hardware paths, note the following:
1. The explicit specification of an LBA on a non-nPartitionable system consists of two fields: sba/lba
2. The explicit specification of an LBA on an nPartitionable system consists of three fields: cell/sba/lba
3. With A.04.xx and A.05.xx, all LBAs under a SBA are implied when explicitly specifying a SBA without specifying any LBA. Therefore, the path specified on a command line can have different meanings depending upon the vPars version, the type of server, and the user intent. For example, the path of x/y can mean any of the following:
  sba=x, lba=y on a non-nPartitionable server running vPars A.03.01 or earlier.
  sba=x, lba=y on a non-nPartitionable server running vPars A.03.02 or later or A.04.xx.
  cell=x, sba=y on an nPartitionable server running vPars A.03.02 or later, A.04.xx, or A.05.xx.
Supported I/O Check your hardware manual to verify that your mass storage unit can be used as a bootable device. If a mass storage unit cannot be used as a boot disk on a non-vPars server, it cannot be used as a boot disk on a vPars server. vPars does not add any additional capability to the hardware.
For information on supported I/O interface cards and configurations, see the document HP-UX Virtual Partitions Ordering and Configuration Guide.

I/O: Allocation Notes

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LBA Example