[plug] recommendation for MySQL server

[Craig Ringer]

> Kill the RAID 5 if you want any database performance, especially on 
> writes. You will want to run on RAID1 or RAID 1+0.
> 
> JLM> Though about that but I'll need the ability to run replace a drive when a drive failure occurs and RAID 5 offers this where the others do not.

Weird. I assume you're talking about the Highpoint RAID on the 
motherboard? The SATA RAID controller in the POST's main 
storage/terminal server hot-rebuilds RAID1 and RAID5, presumably also 
RAID1+0 and RAID50. Perhaps I'm misunderstanding - are you saying that 
you can't hot-replace a failed drive with the other RAID schemes?

Personally, if you take your server availability and your data 
seriously, I would avoid the Highpoint RAID controller. It's mostly 
software RAID, with some BIOS hooks to allow the BIOS to see RAID 
volumes as single drives. The drivers do most of the work, so your CPU 
and cache will suffer. Again, if you want database performance this is 
not the way to go. Before you buy a RAID 5 configuration with Highpoint 
RAID, see if you can get a loaner to do some benchmarks on. I guess it 
could be alright if (write) performance doesn't matter.

I'd be thinking seriously about 'real' hardware RAID. Options for 
hardware ATA RAID are available from Adaptec (closed-source drivers - 
yay) and 3ware (open-source drivers in 2.2 and 2.4 kernels) or there are 
an endless selection of SCSI RAID vendors to pick from. At least with 
hardware RAID you get good performance and usually hardware that's been 
designed for serious work, plus if it's ATA RAID you're getting a low 
price-per-megabyte.

At the beginning of your first message you said that cost wasn't an 
issue. I don't know what the 'scale' and performance requirements of the 
work you're doing on the machine is, nor how critical it is, so I can't 
give any real opinion. If you need really solid uptime, data protection, 
good performance, etc, I'd be thinking about moving upmarket of your 
current specs to a server board and real hardware RAID.

Craig Ringer

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