saconfig expand and LVM

[Fred Ruffet]

hi all,

I have just crashed a server. It's a new server, comming with 4 disks connected to a RAID controler. OS is pre-installed on the 2 firsts, bound in a RAID 0+1. I wanted to expand this RAID with the two other unused disks.

I did the following steps :
$> saconfig /dev/ciss1 -E 0 -p 1I:1:6 -p 1I:1:5
$> saconfig /dev/ciss1 -E 0 -c 273

Using saconfig, I can see size has been increased. But vg00 is still the same size. Then I thought reboot would be a good thing as long as it does a sync. It looks like it did. Just before shutdown, it tells :
CISS: RAID SA controller on hardware path 0/3/0/0/0/0 has detected a logical
drive status change:
Logical drive 0 transitioned from OK to QUEUED FOR EXPANSION
Drive type: RAID 1+0 - Disk Mirroring
CISS: RAID SA controller on hardware path 0/3/0/0/0/0 has detected a logical
drive status change:
Logical drive 0 transitioned from QUEUED FOR EXPANSION to EXPANDING
Drive type: RAID 1+0 - Disk Mirroring
CISS: RAID SA controller on hardware path 0/3/0/0/0/0 has detected a logical
drive status change:
Logical drive 0 transitioned from EXPANDING to OK
Drive type: RAID 1+0 - Disk Mirroring
CISS: RAID SA controller on hardware path 0/3/0/0/

But then it didn't manage to boot on the newly expanded vg00. It goes into a system panic, complaining about LVM structure.

Question : What was wrong ? (expansion was ended before I reboot).

Is there a way to get it back ? I still have an other server of the same kind, and I could try to ignite.

Fred

[Tim Nelson]

Unless I misunderstood something. You cannot change the underlying disk structure, especially for vg00, and expect things to be ok.

If you created an Ignite image before you started then boot it and recover.

[Torsten.]

If you have running 11.23 or 11.31 go to LVM "-lm" mode and run vgmodify!

see

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01920387/c01920387.pdf (BSC link updated by admin)

[Fred Ruffet]

Well, in fact, I increased the RAID size. So I expected the PV size to increase. As it didn't I thought a sync would do.

Now I know my system is crashed, and yes I will go into an ignite process.

But what I would like to know, is how do you increase a PV size ? What is the purpose of expanding RAID if you can't extend PV and underlying LVM structure ? Or is my problem specific to vg00 ?

Fred

[Fred Ruffet]

Torsten> I'm going at it immediatly. Seems good for me.

[Tim Nelson]

In 11.23 vgmodify options were added to increase max_pe and such for the once create time only settings. Read through the instructions to find that it is not a simple process.

I guess 2 comments come to mind:

1) Attemting to change vg00 has some different challenges then other vgs. If you were simply concatenating storage to the end of the existing set then maybe. Changing the stripe/layout, NO.

2) I have experienced with arrays that, yes, you can grow the lun, but typically the OS or at least the VG needs to come offline in order for the changes to be seen by the OS. In effect there is no online ability at the OS side. ( this can be argued, try it.. grow a lun then run diskinfo on the OS side ).

Another observation. Not sure how you get a raid 1+0 with the intitial two physical disks.

[Fred Ruffet]

Tim> That was just an increase, yes. Now, I'm gonna try it. If I can't I will go through Ignite.

Regarding the 0+1, I asked myself the same thing. It's the HP Instant ignition system, so we should ask HP for it :)

[Torsten.]

Regarding the RAID level:
It would be interesting to the output of

# sautil /dev/ciss1
# saconfig /dev/ciss1

once your system is up again.

BTW, is this the P400?

[Fred Ruffet]

Torsten, I already saved saconfig output (and yes, it is P400). It includes the 2 disks I added and states RAID 0+1, but it already did before. Even if a RAID 0+1 on 2 disks doesn't make much sense.

$> saconfig /dev/ciss1

******************** SmartArray RAID Controller /dev/ciss1 ********************

Auto-Fail Missing Disks at Boot = disabled
Cache Configuration Status = cache enabled
Cache Ratio = 25% Read / 75% Write

---------- PHYSICAL DRIVES ----------

Location Ct Enc Bay WWID Size Status

Internal 1I 1 8 0x5000c50007805f31 146.8 GB OK
Internal 1I 1 7 0x5000c5000780f52d 146.8 GB OK
Internal 1I 1 6 0x5000c500073fce01 146.8 GB OK
Internal 1I 1 5 0x5000c5000780c645 146.8 GB OK

---------- LOGICAL DRIVE 0 ----------

Device File = c1t0d0
RAID Level = 1+0
Size = 279552 MB
Stripe Size = 128 KB
Status = OK

Participating Physical Drive(s):

Ct Enc Bay WWID
1I 1 8 0x5000c50007805f31
1I 1 7 0x5000c5000780f52d
1I 1 6 0x5000c500073fce01
1I 1 5 0x5000c5000780c645

Participating Spare Drive(s):

None