XIV and AIX Part One - Device drivers
anthonyv 2000004B9K Comments (2) Visits (20231)
So your planning to attach your XIV at an AIX host?
Here are some best practices for you to follow.
1) Native XIV detection
The XIV uses a path control module (PCM) that plugs into AIX MPIO. Depending on your AIX level the XIV will be recognised natively by AIX without additional software.
This is nice because it means you can simply run cfgmgr and detect the XIV hdisks without doing any system changes.
If your on the following AIX levels (with TL and SP) then your AIX system will detect the XIV natively. Frankly its a good excuse to perform a system update.
AIX Release APAR Bundled in
AIX 5.3 TL 10 IZ69239 SP 3
AIX 5.3 TL 11 IZ59765 SP 0
AIX 6.1 TL3 IZ63292 SP 3
AIX 6.1 TL 4 IZ59789 SP 0
If your running VIOS, you need to be on VIOS v2.1.2 FP22 to recognise the XIV natively.
Natively detected XIV devices will look like this when displayed using the command:
lsdev -Cc disk
hdisk2 Available 03-00-02 MPIO 2810 XIV Disk
2) XIV Host attachment kit
If you are not on the levels listed above, you can install the XIV Host Attachment Kit to get XIV support.
However at lower AIX and VIOS levels there are issues with queue depth and round robin (its limited to 1)
The following releases do not have the queue depth issue, so they are better levels to be on:
AIX 5.3 TL 10 SP 0,1 and 2
AIX 6.1 TL 4 SP 0,1 and 2
VIOS v2.1.1.x FP-21.x
If your on level lower than those, you can still install the Host Attachment Kit to get XIV device support.
To detect XIV volumes when using the XIV Host Attachment Kit, you use the command xiv_attach.
The very first time you run xiv_attach you will need to reboot the host. After that you can use xiv_attach or cfgmgr (without reboot).
XIV devices detected by the xiv_attach command will look like this when displayed using the command:
lsdev -Cc disk
hdisk3 Available 02-01-02 IBM 2810XIV Fibre Channel Disk
3) The xiv_devlist command
Regardless of what level of AIX your running, you should install the Host Attachment Kit (HAK) to get the wonderful xiv_devlist command.
The HAK uses a specially packaged version of Python which is renamed XPYV (to not get in the way of any system Python already installed).
Just installing the kit does not require a reboot.
The xiv_devlist command is the equivalent of what SDD gave you with datapath query device.
It lets you map an AIX device (an hdisk) to an XIV volume. Its a tool you don't want to live without.
In the example below you can see the hdisk number on the left,
but all the other information (volume size, number of paths, volume name, XIV host) all come from the XIV itself.
This is really useful information.
root@system] # xiv_devlist
Device Size Paths Vol Name Vol Id XIV Id XIV Host
/dev/hdisk26 204.0GB 6/6 PROD-3050 188 7802844 PROD-prd
/dev/hdisk27 42.9GB 6/6 PROD-3051 189 7802844 PROD-prd
In my next blog entries I will tell you about zoning and what fcs, fscsi and hdisk variable work best with XIV.
I will also share a great way to update them.