Re: RAID Levels

On Tue, 15 Jul 2003 14:52:55 GMT, Brian Peasland <dba_at_remove_spam.peasland.com> wrote:

>The term "level" when dealing with RAID, IMO, is a misnomer. This tends
>to mean that one level is "higher" than another. But I digress...
>
>RAID 0 is not true RAID in that it does not provide any redudancy. It
>only stripes the data across multiple disk volumes.
>
>RAID 1 performs mirroring. It makes a duplicate. RAID 1 is pretty good
>for write intensive software like Oracle.
>
>Many people prefer the redundancy of mirroring, coupled with the speed
>of striping so they combine RAID 0 and RAID 1 to get RAID 0+1. This may
>be what you are referring to as RAID 10.
>
>The downside of any RAID 1 implementation is that requires twice as much
>disk. But you get great performance. To save on disk, many people like
>RAID 5. RAID 5 stripes the data across multiple volumes and it stores
>parity bits on the disks as well to help with redudancy. RAID 5 does
>suffer from a write penalty. Your write operations can take twice as
>long. So many DBAs stay away from RAID 5 if at all possible.
>
>RAID 3 is similar to RAID 5 in that it stripes and stores parity bits.
>But the parity bits are stored on a special volume. So the write
>performance isn't as bad as RAID 5.
>

So, if I'm currently running RAID-5, but am about to upgrade and reconfigure my servers, I would benefit by going to RAID-1? Any rules of thumb of how much improvement I would see?

Thanks,
Harry Boswell Received on Tue Jul 15 2003 - 16:26:06 CDT