Re: what is fsck's "slowdown"?

From: Marc G. Fournier <scrappy_at_hub.org>
Date: Sat, 4 Sep 2004 00:33:27 -0300 (ADT)
On Fri, 3 Sep 2004, Don Lewis wrote:

> On  3 Sep, Marc G. Fournier wrote:
>>
>> I'm running another fsck on a 4.x system ... I know 5.x brings in the
>> background mode for it, which would definitely make my life easier, *but*
>> ... when running fsck, it says its using up 99% of the CPU:
>>
>> # ps aux | grep fsck
>> root    67 99.0  5.0 184252 184284  p0  R+   12:46PM 254:16.68 fsck -y /vm
>>
>> now, its a dual CPU system ... on an MP system, is it not possible to have
>> it parallelize on a file system, so that it makes use of all available
>> CPU?
>>
>> For instance, right now, its in Phase 4 ... on a file system where ctl-t
>> shows:
>>
>> load: 0.99  cmd: fsck 67 [running] 15192.26u 142.30s 99% 184284k
>> /dev/da0s1h: phase 4: cyl group 408 of 866 (47%)
>>
>> wouldn't it be possible, on a dual CPU system, to have group 434 and above
>> run on one process, while group 433 and below running on the second, in
>> parallel?  Its not like the drives are being beat up:
>
> Would the file system in question happen to be full of UNREF files that
> fsck is deleting?

mostly 'ZERO LENGTH DIRECTORY' ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy_at_hub.org           Yahoo!: yscrappy              ICQ: 7615664
Received on Sat Sep 04 2004 - 01:33:37 UTC

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