[CentOS] slow system

Sat Jan 13 05:39:46 UTC 2007
Craig White <craigwhite at azapple.com>

On Fri, 2007-01-12 at 23:16 -0600, Les Mikesell wrote:
> Craig White wrote:
> >>> I have software RAID level 1 and the mirrored drives are the master &
> >>> slave on the primary controller and I'm thinking that is my mistake.
> >>>
> >>> Is there a simple method for changing the configuration of md before I
> >>> switch the slave drive to be the slave on the secondary controller?
> >>>
> >> I think they will pair up automatically if you shut down cleanly
> >> and move the connector.  If not, just 'mdadm --add' it back after
> >> it comes up with a missing member.  If you have to add it back,
> >> the drives will have to resync so there is a small risk of
> >> failure during the process.
> > ----
> > great thanks - am I right in thinking that having both mirrored drives
> > on the same controller master/slave is likely a cause of slowness?
> 
> It will make some difference on writes, but reads should only
> be done on one of the drives anyway.  I doubt if it makes a huge
> difference unless you have an application writing all the time.
----
here's my problem - system was ok and mother board died. Purchased a new
motherboard and this is what I get...

# hdparm -t /dev/md1

/dev/md1:
 Timing buffered disk reads:    4 MB in  3.68 seconds =   1.09 MB/sec

which is dreadfully slow

Thanks

Craig