Re: XFS drops create/delete files to 6.6% of EXT3 (software raid) and to 0.6% of EXT3 (3ware hardware raid)

[Eric Sandeen <sandeen@sandeen.net>]

Michael Darling wrote:
> I am preparing a new server, and benchmarking EXT3 against XFS, both using
> software RAID and hardware RAID using a 3ware 9650SE-4LPML.
> 
> Using bonnie++ as a benchmark, I am seeing significant performance boosts in
> my block sequential reads and writes moving from EXT3 to XFS.  I am aware
> that XFS won't create and delete files as quickly as EXT3, however I am
> seeing drops from 29455/second to 1957/second using software RAID, and from
> 32524/second to 189/second using hardware RAID.  I'm not sure if when using
> software raid, if creating and deleting files should drop to 6.6% of EXT3.
> But, what I'm pretty sure of, is when using hardware raid, that creating and
> deleting files shouldn't drop to 0.6% of EXT3.

Chris Mason reminded me that bonnie++ may not be creating enough files
to actually cause much if any IO on ext3; you might play with the -n
option to get it to the point where it's actually doing a significant
number of creates (I don't know what the default is offhand... checks
source... it's 16k maybe?) but more sustained creation might be interesting.

-Eric