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:
> Eric, for the numbers you provided, are you using a single drive,
> software raid, or hardware raid?  If a hardware raid, is it a 3ware card?

it's a simple partition on a sata drive.

> I hadn't seen the nobarrier mount option before.  Using that changes
> sequential creates from about 190/second to about 2500/second, and
> changes sequential deletes from about 170/second to about 3700/second.

I wasn't recommending, necessarily, that you use it, but was just
looking for bottlenecks...

> I don't yet have a BBU for the 3ware card, but would certainly get one
> if we go with the 3ware card before we start putting real data on the
> raid.  Am I right that with a BBU unit and a battery backup for the
> server as a whole, that nobarrier would be safe to use?
>  
> Not using nobarrier, but using logbsize 256k changes sequential creates
> from about 190/second to about 270/second.  So, it's an improvement, but
> no where near where a software raid performs (1600/second) or where the
> hardware raid performs with nobarrier.

Default mkfs & mount w/ 256k logbufs:

xfs,256k logbuf:	1353/s

> On Thu, Apr 24, 2008 at 1:33 AM, David Chinner <dgc@sgi.com
> <mailto:dgc@sgi.com>> wrote:
>     > So I played with this a little on 2.6.25, on plain partitions.
>     >
>     > I saw similar numbers; for example, sequential creates:
>     >
>     > ext3:         23698/s
>     > xfs:            319/s
>     > xfs,nobarrier:         4478/s
> 
>     And with logbsize=256k?
> 
>     Cheers,
> 
>     Dave.