Re: U320 Large Array Performance

["Rick Smith" <rgsmith72@xxxxxxxxxxx>]

Steve,
	As a test, I shortened the size of one of the 15 disks in the array (using 
fdisk) in order to create a slightly smaller filesystem and thus requiring a 
smaller number of allocation groups. The resultant filesystem only required 
256 allocation groups and I was able to improve performance over 14 disks 
for the first time. The results from xfs_bmap for this 15 disk array was 
very similar to the output that I sent you for the 14 disk array. There were 
no extent gaps between files written in succession and each group of files 
seem to have the same AG.
	I feel the problem is the result of >256 allocation groups. Any thoughts on 
this?
Rick

> From: Steve Lord <lord@xxxxxxx>
> To: Rick Smith <rgsmith72@xxxxxxxxxxx>
> CC: linux-xfs@xxxxxxxxxxx
> Subject: Re: U320 Large Array Performance
> Date: 05 Feb 2003 12:02:08 -0600
>
> On Tue, 2003-02-04 at 16:47, Rick Smith wrote:
> > Steve,
> > 	Here is the output from xfs_info, please excuse the formatting. I am 
> using
> > a chunk size of 4K in the raid. Larger sizes seem to degrade 
> performance.
> > Thanks for your help.
> >
>
> Can you do one more thing for me, with these configurations send me the
> xfs_bmap -v output for a file on each filesystem.
>
> Thanks,
>
> Steve
>
> --
>
> Steve Lord                                      voice: +1-651-683-3511
> Principal Engineer, Filesystem Software         email: lord@xxxxxxx

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