trace jfs

[Kenn Chen]

how to check whether my unix system is running online jfs or jfs ? if online jfs , could i increase my root / file system online ??

[Sridhar Bhaskarla]

Online JFS is an add-on enhancement to vxfs. You need to have it installed seperately.

You can verify if Online JFS is there or not by

#swlist |grep OnLine

If it is there and if your / is vxfs, you can do it online

#fstyp /dev/vg00/lvol3 (or whatever the lvol that is mounted as /)

If you get an answer as vxfs then you can increase the size of /

#lvextend -L new_size_in_MB /dev/vg00/lvol3
#fsadm -b new_size_in_KB /

new_size_in_KB=new_size_in_MB*1024

If your / is not vxfs or if you don't have Online JFS, you can create ignite tape and recover the OS with a differently sized root logical volume

-Sri

[Patrick Wallek]

As far as I know, you can NOT extend the / lvol. /, /stand, and primary swap have to be the first lvols on the disk and have to be contiguous. If you were to extend /, then it would no longer be contiguous.

Why do you need to extend the / lvol? That is one that you should never have to extend. If anything, look for large files that do not belong. Look for 'core' files that do not belong.

One of the classic things to look for is a file in /dev/rmt called 'om' (the letter o followed by m, rather than the correct 0m -- zero m) or lm (lowercase L, rather than 1m -- number 1) that someone mistakenly created.

[Sridhar Bhaskarla]

Patrick,

You are right. That was my overlook. I just didn't think of it.

Zuang,
If you are lucky enough, you may find some free extents after the root vol (pvdisplay and keep scrolling). If the lvol after root vol is not an important file system, you can remove it and free up extents.

Otherwise, we are left with only one option if you really want to increase /. Take a make_recovery tape and re-ignite the box with a different root lvol size.

-Sri

[S.C. Fun]

If u really wants to increase /, try this:
pvmove lvol4, ... lvol8 to another PV (of course u need another PV). then try extend the lvol3 (assuming Allocation is default:strict/contiguous). Then pvmove lvol4 ... lvol8 back to your root disk.

CAUTIOUS: Do this when u really need to do it!
Rgds,
S.C. Fun

[linuxfan]

Hi Idris,

Well frankly if possible use make_tape_recovery or make_net_recovery option.
Its pretty straight forward and is a tested solution.

You will have to be extra careful when following the option of moving around lvols and extending lvol3.

-Regards
Ramesh