hello everyone, I have an AIX6.1 machine and i want to convert the rootvg to scalable format because i need to increase the size of specific file systems and i cannot do it with its current state. I know that in order to perform this operation the volume group must be varied off so is there a way to do this possible if i boot through service mode? Take also into consideration that rootvg is mirrored also so maybe i will need to break the mirror too or not? Thank you
First off, I have never tried to convert the rootvg into a scalable.
Reasons:
Usually rootvg should be sufficient for it's parameters. If you have application data etc. on the rootvg, you might want to think about adding additional disks and form a new VG on them to simply separate the OS from your application data.
Normally you want your rootvg for a production system as clean as possible which means that only OS stuff resides there with the one or other small exception.
If you want to give it a try anyways, I would do the following:
- Take a mksysb backup including all relevant file systems (check that you don't have excludes listed that might relate into a problem on a possible restore)
- Break the mirror
- Boot in service mode
- varyoffvg rootvg and try to issue the chvg and convert it to scalable
well the reason i want to convert rootvg to scalable (even big may be enough) is because of my backup software. it uses /var and /opt and for the upgrade it needs additional space that is not available right now. i tried to convert rootvg to big because i thought this change could be done while the volume group is active but still does not work. then i boot through service mode and tried to convert it but still i get error. i suspect that maybe is because i didnt break the mirror? i would try again but first break the mirror.
OK, but: with a classic VG you can use a PP size of up to 128G. Every PV ca hold 1016 PPs, which makes the maximum size of a PV in a classic VG ~1.2 TB. You can add up to 32 PVs to a VG, which makes the possible disk space in a rootvg 32 x 1.2 ~ 38TB. I do not know your backup software but this is perhaps enough.
Another take is: the software will perhaps not write to "/var" or "opt" directly but to some subdirectory "/var/somewhere". It is no problem to mount a FS with more space there which comes from a separate volume group.
If you want to increase the PP size for your rootvgs which you install via NIM you find a detailed how-to here.
I hope this helps.
bakunin
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thank you both solutions seems very good.
i think the easiest way is just create a link from the directory under /var and /opt or just mount a separate file system like you said. thats the easiest and fastest way to do it. i would like to avoid an mksysb restore.
I always strive to keep rootvg (or its equivalents on other OSs) empty apart from what is necessary to boot the server and get on the network. Even backup software can be installed again and good software will offer you the ability to read the backup catalogues from any tapes you have written so you can rebuild whatever it needs to get your real restores running.
For me, a rootvg should be the smallest disk you can see from the SMS menus (where you trigger the initial install or mksysb recovery from) and if local, it needs to be a pair. 36Gb (each) should be plenty. I have one server with a pair of the and only 12Gb allocated on each. I have no plans to allocate any non critical (so far as the OS is concerned) space in there. It's a waste perhaps,but I prefer to see it as a bearable cost.
We even force users we define using a home directory outside rootvg. There is no problem creating a filesystem with a mount point of /var/backup-logs or whatever, and it is probably safer that creating a separate filesystem with a symbolic link to it.
Growing rootvg might mean that you can no longer back it up with a mksysb and you will have problems restoring it too as your requirements are bigger than usual.
Robin