vxfs logical volume size issue

[Christopher Lau]

I have an L1500-7x running HPUX 11.11

I know the biggest size for 11.11 on a logical volume is 2TB.

1) What are the pros and cons of creating a 300GB vxfs LV vs creating 3 x 100GB LVs? I am planning on putting about 10,000 files on it. The files and directories on this LV are static. Subdirectories will be less than 5 levels deep. pdm application will read from this LV only. No writing.

2) Is it a bad idea to create a logical volume greater than 100GB, 200GB, etc. before we get into performance issue, backup and recovery issue, etc. Where is the cut off point?

Thanks for the help!

[Sridhar Bhaskarla]

Hi,

The biggest problem that you may get into is filesystem corruption. You will lose a lot of data if it is a big filesystem. Performance may also be impacted as there is a chance for extensive fragmentation. There isn't any hard rule about the size of the filesystem. However, I wouldn't like to go beyond 30-50GB for my active filesystems. I do have 500MB|terabyte filesystems for oracle backups as I am not too concerned about performance on them.

-Sri

[David Child_1]

As Sridhar mentioned; don't put all your eggs in one basket unless you need to.

Really I would say if you don't have to go with a larger file system then don't. It really doesn't buy you anything, but potentially does have a downside. Of course if one large repository is required then that's that.

David

[Rajesh D L · Accepted solution]

Hi Christopher,

There is no cut off point as such as far as Veritas is concerned, for performace issues. You can comfortably create an LV of 300 GB and put files on it (small LVs as possible as recommended though !!). Files in the range of 10000 and all wont make any problem. I started having problem only when the number of files crossed a million. But clearly identify the LUNs for the LV and create the volume specifically on those disks. As a best practice, use the "s" option to specify the size in sectors if you are using "vxassist" to create the volume. This will help to fully utilize the disk space and fragmentation can be minimized. Free size in sectors can be obtained from "vxdg -g diskgroup free"

Regards,
RDL.

[Rajesh D L]

Hi,

The commands mentioned in my previous posting are only for Veritas volume manager, not LVM.

regards,
RDL.

[Christopher Lau]

Thanks all for the help.