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Re: LBA to File?

To: Andy Skunza <askunza@xxxxxxxxxxxxxxx>
Subject: Re: LBA to File?
From: Steve Lord <lord@xxxxxxx>
Date: 07 Mar 2003 09:33:57 -0600
Cc: linux-xfs@xxxxxxxxxxx
In-reply-to: <3E68ACFD.20702@xxxxxxxxxxxxxxx>
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On Fri, 2003-03-07 at 08:30, Andy Skunza wrote:
> Stephen Lord wrote:
> > 
> >Possibly the way your app runs is making things worse. There is a script
> >in  the cmd/misc directory called xfsstats.pl you can watch log activity
> >with this. In particular xs_log_writes and xs_log_blocks. If log_blocks
> >is not a reasonable multiple of log_writes then you are doing a lot of
> >very small writes.
> >
> >Steve
> >
> What is a "reasonable multiple" of log_writes to log_blocks? Would 22 be 
> unreasonable? And, how to use xfs_stats.pl per xfs partion?
> 
> Thanks,
> andy

The stats are global and not available on a per fs basis. You can clear
the stats with

echo 1 > /proc/sys/fs/xfs/stats_clear

So you can measure more controlled periods of time.

Perfection is 64, the more recent your code the closer you should get,
we have been removing synchronous transactions from the code. My
workstation which has been up 27 days is averaging a ratio of 52.
It also depends on what you run, something which does O_SYNC writes
all the time can hammer it.

Steve

-- 

Steve Lord                                      voice: +1-651-683-3511
Principal Engineer, Filesystem Software         email: lord@xxxxxxx


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