[CentOS] 3Ware 9550SX and latency/system responsiveness

Simon Banton centos at web.org.uk
Tue Oct 2 17:27:08 UTC 2007

At 13:03 -0400 2/10/07, Ross S. W. Walker wrote:
>Have you tried calculating the performance of your current drives on
>paper to see if it matches your "reality"? It may just be that your
>disks suck...

They're performing to spec for 7200rpm SATA II drives - your help in 
determining which was the appropriate elevator to use showed that.

>What is the server going to be doing? What is the workload of your

Originally, it was going to be hosting a number of VMWare 
installations each containing a separate self contained LAMP website 
(for ease of subsequent migration), but that's gone by the board in 
favour of dispensing with the VMWare aspect. Now the websites will be 
NameVhosts under a single Apache directly on the native OS.

The app on each website is MySQL-backed and Perl CGI intensive. DB 
intended to be on a separate (identical) server. All running 
swimmingly at present on 4 year old single 1.6GHz P4s with single IDE 
disks, 512MB RAM and RH7.3 - except at peak times when they're a bit 
CPU bound. Loadave rarely above 1 or 2 most of the time.

Which is why I'm now focused on getting the non-VMWare approach up 
and running so I can profile it, instead of getting hung up on 
benchmarking the empty hardware. I'd never have started if I'd not 
noticed a terrific slowdown halfway through creating the filesystem 
when doing an initial CentOS 4.3 install many many weeks ago.

>It may be that it will work fine for what you need it
>to do?

Yeah - but it's the edge cases that bite you. Can't be doing with a 
production server where it's possible to accidentally step on an 
indeterminate trigger that sends responsiveness into a nosedive.


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