Linux mkfs.xfs parameters for large files

Linux mkfs.xfs parameters for large files

[Jamie Tufnell]

Hi,

I've done some research into how to best-prepare our Linux (2.6.18)
XFS filesystem for a read-heavy workload of mostly large files (files
between 50MB and 500MB) and I have some questions on block-sizes /
extents.

My experience with other filesystems leads me to believe I should
experiment with large block-sizes for this application.  In trying to
do so, I found that the Linux XFS implementation forces the block size
to not exceed the page size -- 4kB -- which seems a bit small in this
case.  At first, I thought this was *really* bad news for me but I've
since read some posts and the impression I'm getting is it's not that
big of a deal?

Can someone please explain why (if that's true)?  I've read that an
extent is one or more "continguous" blocks, so should I simply tune
the extent size in the same way I was expecting to tune the
block-size?  Are there any other mkfs.xfs parameters I should
experiment with.. so far I plan to use stripe width/unit as the
filesystem will be on a striped RAID.

Lastly, would you recommend XFS for this application?  Is there a
better filesystem for what I'm trying to do?

Any help greatly appreciated!

Thanks,
J.

Re: Linux mkfs.xfs parameters for large files

[Eric Sandeen]

Jamie Tufnell wrote:
> Hi,
> 
> I've done some research into how to best-prepare our Linux (2.6.18)
> XFS filesystem for a read-heavy workload of mostly large files (files
> between 50MB and 500MB) and I have some questions on block-sizes /
> extents.
> 
> My experience with other filesystems leads me to believe I should
> experiment with large block-sizes for this application.  In trying to
> do so, I found that the Linux XFS implementation forces the block size
> to not exceed the page size -- 4kB -- which seems a bit small in this
> case.  At first, I thought this was *really* bad news for me but I've
> since read some posts and the impression I'm getting is it's not that
> big of a deal?

In your careful benchmarking & testing, which aspects of the performance
you've found does not meet your needs or expectations?  That's always a
good place to start.

-Eric