On Wed, March 10, 2010 09:04, Dan Nelson wrote:
> In the last episode (Mar 10), John G. Heim said:
>> I have read (and have been told) to stay away from RAID-5 for
>> update-intensive systems. Are there performance concerns with RAID-10
>> well? We will be buying from Dell (done deal for reasons too
>> to go into) and the disks they're selling are 146 Gb. I can get up to 8
>> of them in the server we're buying. I asked them about just getting 2
>> disks and going with RAID-1.
>> My understanding is that with RAID-10, the system can do multiple reads
>> writes simultaneously so throughput is improved oversystems w/o RAID or
>> RAID-1. But the same logic would apply to RAID-5 only it doesn't work
>> that way.
> RAID-5 has an extra penalty on small random writes due to the I/O required
> to maintain the parity blocks (it does 2 reads and 2 writes for every
> your app does). RAID-10 is just a mirror so it doesn't have to worry
> Dan Nelson
If you can get the disk cheap you might want to get one or two extras and
keep them as spares.
William R. Mussatto