MySQL on RAID 1

[Miroslav Lachman]

list, mailing wrote:
> I'm setting up a HW RAID 1 mirror setup with two 500 GB Drives.
>
> How much slower will MySQL run? (Installing whole OS on the RAID)

We are running MySQL on gmirrored SATA II disks (500GB or 1TB). It is 
somewhat slower on writes compared to single disk (I don't have exact 
numbers), but it is running fine and date is more secure.

> Not noticeable or very slow?
>
> Also if a drive fails will I simply be able to shutdown drop in a new drive
> boot up.
> Having MBR working fine and auto build RAID on new drive?

I am able to replace failed disk drive without shutdown. Faild disk 
drive is already datached from gmirror, so then it must be detached from 
ATA chanel by atacontrol detach command.
After inserting new drive, you can do `atacontrol attach ata2` + 
`gmirror forget gm0` and `gmirror insert gm0 ad4` (for example)


Miroslav Lachman