Re: 1x 3ware controllers vs. 2x 3ware controllers

On Fri, 30 Jul 2004, Jim Buttafuoco wrote:

I have a dual XEON 3.2 Ghz system 12 G of ram with a 3ware 8506-8 in it
(8 250 G drives).  The hard raid performance was very bad.  with the
load avg going over 40.  I then switched over to JBOD and software raid.  
The IO wait times are really high and the performance sucks.  Very hard
to explain to my boss where the $20k went. The system is a database
server (postgres).  I tried both kernel 2.4 and 2.6 with the same
problem.  I am now in the process of testing the adaptec raid
controller.

You should never ever ever use raid5 with something that is write 
intensive, such as a database server. Raid5 is a cost compromise that is a 
little of everything, if you want protection and speed at the same time, 
you should use raid1 (and possible raid0 the raid1:s).

I learnt this the hard way running a nntp (news) server.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se