[CentOS] Re: plan of action?

Feizhou feizhou at graffiti.net
Fri Sep 16 04:11:56 UTC 2005

> 2. The problem with Brian is that he goes on and on, but it's actually 
> never CentOS stuff, like arguing what kind of Raid and states his 
> opinion as facts.

Heh. His opinion just happens to concur with mine in that 1) 3ware 750x 
and  850x are absolutely disasters in RAID 5 mode for performance and 2) 
if you do want to do RAID 5 on a 3ware card, go get a 950x series card.

Where I work, we host millions of email boxes and run hundreds of 
fileservers where the emails are stored. When the team was on the 
lookout for new fileservers which would use a hardware raid card about 
two years ago, they chose 3ware. We could only fit 6 disks in the case 
and so there was debate about maximising space versus performance.

I made it clear that raid 5 would be slow and a disaster should any disk 
take a hike. All I had for proof were public benchmarks on software vs 
hardware raid and which included different hardware raid cards done a 
year earlier. Of course, since we had not have any experience with the 
card and they had only had experience with Mylex Raid cards, what I said 
was taken as an opinion only. The team went ahead with raid 5 since I 
was only the mail admin and i cannot demonstrate that raid 5 would be slow.

Now the team configures three mirrored arrays instead of running a RAID5 
array after being burned badly by the production problems caused by 
RAID5 mode. Bryan did not make opinions about the different kinds of 
RAID and what 3ware card you should use. He gave detailed explanations 
on why RAID5 on a 3ware 950x card with a ram module would be fast, why 
it does not perform on the older series and that has been proven where I 
work. We have a ten disk box that uses a 950x 3ware card and those ten 
disks are configured in raid5 mode. It performed while being used as an 
emergency mail queue doing thousands of deliveries per minute. I was 
amazed but now I know why thanks to Bryan.

Drop the Bryan is a nuisance mentality.

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