Number of filesystems on a server

[John Tyler]

Hello!

What is the pros and cons of having large number of filesystems?(100 +)

We run HP/UX 11.0 on N-Class connected to XP512.

What is the impact of creating small filesystems (like 200 mb) which since the LVs are created at LUN level and not at disk level.

Any feedback will be greatly appreciated.
thanks,
Kevin.

[Pete Randall]

Kevin,

Actually, you're better off having a large number of smaller file systems than one with a huge number of files since there's a performance hit.

Pete

[Stefan Farrelly]

Performance wise I cant think of any cons of having a large number of filesystems, or any pros.

The default max number of logical volumes per volume group is 255 so its designed to cope with a large number.

For aministration I would definitely prefer a smaller number of filesystems/lvols. Thats what weve been doing lately, reducing ours to as few as possible. That way there are less requests for more space (as we have huge filesystems/lvols with tons of space on) and performance and space analysis using sar, top, glance, iostat etc. are a lot lot easier with a few big filesystems than hundreds of small ones.

[Stefan Farrelly]

I think the performance hit Pete is talking about is only if you have a large number of files per filesystem. I seem to recall the discussion being around 100,000-150,000 files per filesystem is the optimum - more and performance reduces.

If you have a hundred filesystems of 200mb then I guess its unlikely your going to squeeze hundreds of thousands of files on each filesystem (200Mb is too small). We run large databases so even with 50-100Gb filesystems were not even nearing tens of thousands of files per filesystem.

[Pete Randall]

Yes, that's what I was referring to - I get dragged away before I could try to search for the thread. Thanks, Stefan.

Pete

[unixdaddy]

I'd probably agree, it easy to maintain and manage. You can also apportion responsiblity for the different filesystems that to have a huge filesystem which everyone uses.

I thnk you need to examine what the application does and what if any users will be using the box (are there alot and do they create a lot of small or large files). the answer to these questions will give you a start in answering your own question.

[Dietmar Konermann]

Hi, folks!

One more thing to consider from a availablity perspective... if you have one large FS then everything is fine unless you need to run a full fsck (can take hours to complete). You simply get more vulnerable to failures with such configs.

Regards...
Dietmar.