Edit: Changed to the current Power Systems Virtual User Group link as of this writing. The links to the presentation and replay may or may not work depending on the status of the transition from the developerworks site.
Originally posted December 2, 2008 on AIXchange
The AIX Virtual User Group (Central Region, U.S.) recently hosted an informative webinar presented by Janel Barfield. Download the presentation or listen to a replay. The topics covered in the presentation and replay go nicely with some AIXchange blog entries (here and here) I previously wrote.
By listening to the webinar, I learned a few other techniques that we can all benefit from. For instance, in my VIO server, I tried creating a file-backed virtual disk (obviously on this test box I was using rootvg; if this were a production machine I’d create another volume group and use that instead):
mksp -fb fbpool -sp rootvg -size 1G
This added a new file system to my rootvg:
lsvg –lv rootvg
fbpool jfs2 4 4 1 open/syncd
/var/vio/storagepools/fbpool
In my environment I did an lsmap –all | more and found a client to try this with. I ran:
mkbdsp -sp fbpool 500m -bd test_disk -vadapter vhost2
Here’s the output I saw:
Creating file “test_disk” in storage pool “fbpool”.
Assigning file “test_disk” as a backing device.
vtscsi5 Available
test_disk
I wanted to see what would appear in the file system that I just created, so I ran:
ls -la /var/vio/storagepools/fbpool
total 1024008
drwxr-xr-x 3 root system 256 Nov 03 15:24 .
drwxr-xr-x 3 root staff 256 Nov 03 15:18 ..
-rw-r–r– 1 root staff 206 Nov 03 15:24 .test_disk
drwxr-xr-x 2 root system 256 Nov 03 15:18 lost+found
-rw-r–r– 1 root staff 524288000 Nov 03 15:24 test_disk
Interestingly, that .test_disk file contains some XML data describing the disk that I just created:
more /var/vio/storagepools/fbpool/.test_disk
When I look at the mapping that exists after creating the disk, I can see:
lsmap -vadapter vhost2
SVSA Physloc Client Partition ID
————— ——————————————– ——————
vhost2 U7998.61X.100BB8A-V1-C15 0x00000007
VTD vtscsi2
Status Available
LUN 0x8100000000000000
Backing device hdisk3
Physloc
U78A5.001.WIH0A68-P1-C6-T1-W5005076801303022-LD000000000000
VTD vtscsi5
Status Available
LUN 0x8200000000000000
Backing device /var/vio/storagepools/fbpool/test_disk
Physloc
U78A5.001.WIH0A68-P1-C6-T1-W5005076801303022-LD000000000000
This shows me that now I have the new virtual disk with the backing device being handled by the newly created file. When I run cfgmgr in my partition that uses vhost2, I see a new disk. AIX running in my partition doesn’t differentiate between the file-backed storage or my normal hdisk-backed storage (hdisk1 is my newly created disk in this instance).
# lspv
hdisk0 00004daa45ffe3fd rootvg active
hdisk1 none None
# lsdev -Cc disk
hdisk0 Available Virtual SCSI Disk Drive
hdisk1 Available Virtual SCSI Disk Drive
I can now use this disk as I would any other on my machine.
On the topic of virtual optical disks, one point brought up in the webinar was that instead of running multiple unloadopt/loadopt commands when using virtual optical disks, you can just use loadopt –f to force the disk image to load, even if a disk image is already loaded. This makes it simpler when using more than one CD to load the OS for instance, as you don’t have to unloadopt before running the loadopt –f command when switching between disk images.
I urge you to take the time to look over the presentation materials as well as listen to the replay to get more information. Also be sure check the Central Region user group archives for some other great webinars.