Re: [Dump-users] slowwwwwww

[Stelian P. <st...@po...>]

Le dimanche 04 novembre 2007 à 15:11 -0800, Todd and Margo Chester a
écrit :
> 2.6.18-8.1.8.el5
> 
> Hi All,

Hi,
> 
> After I wiped my hard drives clean of CentOS 4.4
> (RHEL 4.4 clone) and installed CentOS 5 (RHEL 5),
> I noticed that everything was slower.  Especially,
> dump, which was 3.5 times slower.
> 
> So, I did some tests from my install CD/DVD's in "rescue mode"
> and the System Rescue CD from http://www.sysresccd.org.
> I used the same backup script (dump) that I use in normal
> boot mode. I stopped the backup after dump gave the first
> estimate of time:
> 
>     "dump" CentOS4.4 (Kernel 2.6.9-42.EL) install CD in rescue mode:
>          transfer rate 8468 KB/s, estimated finish 2:09
> 
>     "dump" CentOS5 (Kernel 2.6.18) install DVD in rescue mode:
>          transfer rate 4422 KB/s, estimated finish 4:10
> 
>     "dump" System Rescue CD (Kernel 2.6.22.9):
>          transfer rate 4370 KB/s, estimated finish 4:15
> 
> Has anyone else seen this?  If so, were you able to fix it?

I guess you'll have to do some cross-tests yourself... The problem could
be related to the filesystem read, the output write, or dump itself.

Try dumping to /dev/null, and compare the speeds on both OSes.

Try using the same dump version on both OSes to rule out dump problems.

If the two tests above do not give any indication, it is probably a
kernel problem (either in the filesystem driver or the disk driver).
Maybe running some filesystem performance tests (bonnie etc) will show
the problem.

Stelian.
-- 
Stelian Pop <st...@po...>