Extending VG00

[Kurt Henning]

We have an N box with two mirrored internal 18gb drives that contain VG00. There is no longer any room to increase LVs, but /var is filling rapidly with Oracle files. I'd like to use two drives that are available through a fiber channel connection. Is this wise?

As far as I'm aware, there is no physical space for additional internal drives. So I either replace the existing drives with larger ones, or find the disk space somewhere else. Will the fiber channel drives be available at boot time? Will this be reliable?

-Kurt Henning

[Kurt Henning]

On reading my message after posting it, I see a little clarification might help. I'd like to extend the exiting VG00 volume group by adding two more mirrored drives to the two that make up the VG now. It's just that these drives are on a completely different hardware path that happens to be via fiber channel.

[Kofi ARTHIABAH · Accepted solution]

I understand that it is not advisable to have drives of different interface types in the same volume group. If your /var is filling up you might want to try the following:

1. Create a vg consisting of the fibre accessible disks
2. Carve out LVs and create filesystems under the /var structure.
you could create a fs and mount it on /var/someoraclestuff/

you would have to be able to then move over all the stuff from their original directory location to the new LV and mount the new LV on the path of the fs that requires more space.

Good luck

[James R. Ferguson]

Kurt:

My preference is to put Oracle archive logs (I assume they are the ones in question) on something other than VG00. In my opinion they are of high enought activity to warrant this. /var is hit enough with non-DBMS tasks. I put Oracle archive logs on another volume group and mirror them there.

...JRF...
...JRF...

[Tim Nelson]

What about separating your application io from your OS. This typically makes backups easier and also causes less trouble because your OS can stay static like it should be. You would have to be in single user mode to enlarge /var unless you have online jfs. The simplist way would be to soft link /var/oraclejunk to someother filesystem that was created on your new disk. the other option would be to change the oracle config to write whatever is running away to the new path. Note: You may wish to fix the root of the problem instead of just moving it around. What files from Oracle are growing at such an alarming rate ? I have seen the concurrent manager log grow 2GB a day if users have debug turned on. Once it was turned off the logfile only ended up to be less than 1mb per day.

[Rita C Workman]

I must concur with what everyone else has said.
May you never have this nightmare......

A previous consultant/Admin, decided the best way to extend vg00 was to use the handy big disk array....so over he extended some lvols of vg00 to gain some space.
Well....after I came... when the hardware failure happened (and it was going to happen)...we (thanks to some great HP support) were able to replace the primary disk & resync it. BUT I lost one o/s filesystem (cause it was all sliced up....) and couldn't save it. It was /opt. It was a nightmare to fix and get everything off the disk array.
So the moral of the story.....
VG00 is the volume group for the Operating System...
...If at all possible, do not store application software on vg00. Create a vg for your apps &/or data.
If at possible, do not store application data on vg00. If you have a fiber channell and access to disks, put your application files there.
They will be far safer.....and vg00 will be the better for it.

Regards,