Expanding root file system

[Tom Ward_1]

I've got a server that the root mirror was broke to gain space and I'm trying to clean it up and remirror.

/ is very small
/tmp is very large, and now spread across both local disks.

There are three disks in the vg00
c0t6d0 a 73GB local disk,
c6t6d0 a 73GB local disk, and
c64t5d3 a 8GB SAN LUN.

/dev/dsk/c0t6d0
--- Distribution of physical volume ---
LV Name LE of LV PE for LV
/dev/vg00/lvol1 19 19
/dev/vg00/lvol2 256 256
/dev/vg00/lvol3 13 13
/dev/vg00/lvol4 13 13
/dev/vg00/lvol5 192 192
/dev/vg00/lvol6 384 384
/dev/vg00/lvol7 201 201
/dev/vg00/lvol8 576 576
/dev/vg00/lvol9 1952 1952
/dev/vg00/lvol10 768 768

/dev/dsk/c6t6d0
--- Distribution of physical volume ---
LV Name LE of LV PE for LV
/dev/vg00/lvol4 487 487
/dev/vg00/lvol9 288 288

bdf |grep vg00
/dev/vg00/lvol3 212992 190976 21928 90% /
/dev/vg00/lvol1 298928 45568 223464 17% /stand
/dev/vg00/lvol8 9437184 6426824 2989392 68% /var
/dev/vg00/lvol7 3293184 2554392 733048 78% /usr
/dev/vg00/lvol9 36700160 29003552 7604144 79% /u01
/dev/vg00/lvol4 8192000 313488 7817152 4% /tmp
/dev/vg00/lvol6 6291456 4188488 2086576 67% /opt
/dev/vg00/lvol5 3145728 2341184 804544 74% /home

My plan is to copy /u01 to a new SAN LUN and get it out of vg00.
Then mirror /tmp (lvol4) to c64t5d3. I was going to break the mirror and then mirror it back to c0t6d0.
Before I do that I'd like to expand / (lvol3). Can I pull this off? Lvol4 is right after lvol3, so if I've moved it to SAN disk can't I grow / without a restore from ignite? Then I would mirror lovl4 back to the root disk and re-establish mirroring.

[Pete Randall · Accepted solution]

Tom,

I think that would work. The usual roadblock is that /stand, swap and / have to be contiuous, but, if you move or shrink lvol4 (/tmp), before growing lvol3, you should be OK.

However, I have to think that just doing an Ignite make_tap_recovery and rebuilding from that might be easier in the long run.


Pete

[Tom Ward_1]

I agree, but it is almost impossible to get down time for this system. I've been trying for months. Even now I can't reboot it after it gets mirrored. Maybe next month if I'm lucky. You can see why I want it mirrored.

[Michael Steele_2]

Hi

You can't get down time because it's a critical server in production? Then I think a whole lot of people would be curious about anything that you did on that box, and especially curious if it was an unsanctioned from the manufacturer procedure.

If I did it, and I have before when installing patches or making changes that don't require a reboot, and are transparent to the DBA's and SAP Admins, then I would tell no one. And hope no one notices.

Changing file systems vg's, I think someone would notice.

[Tom Ward_1]

I don't do changes without going through change control. This isn't something that being done on the side or under the table. I don't know what gave you that impression.

I wouldn't take a chance doing something like this without an approved change request to cover things.

[Abbott Vascular]

Hi, Tom -

You didn't mention whether or not you are using Online JFS. This potentially could save you if you have it, but would make any significant change impossible without at least a umount of the FS. Another suggestion, even as a temporary until you can get downtime, why not add a SAN LUN to your vg00 of say 30-50GB? Then you can simply increase your / filesystem (assuming that you're not stuck with allocation and/or contiguous space issues). As far as change control goes, our site has implemented something we call "master standards" where for certain activities such as increasing a filesystem, we simply fill out the appropriate CR record and no approval is required. You might want to set this up (it could take you some time at first, but it's worth it down the road!) as part of this operation- typically this applies to well documented procedures that are repeatable.

As to shrinking lvol4, again, with Online JFS, you're in a much better place - do you have it?

[Abbott Vascular]

Ooops :) I forgot and signed in as my group ID, I have a personal one for assigning points and will reply below. My ID is RC Park.

Thanks!

[RC Park]

Hi, I replied as Abbott Vascular, but if you assign points, please put them here.

Thanks!

[chris huys_4]

Hi Tom,

Abbott Vascular/RC park, makes a good comment, without onlineJFS, the procedure cant be done "online", because the "to be extended" root filesystem, cant be unmounted once the system is booted.

Greetz,
Chris

[Tom Ward_1]

It worked!

/tmp was mirrored to SAN disk, and then removed from local disk. That freed up extents right next to /. Next / was expanded on to the free space and finally /tmp was moved back to local disk.