Re: What's major different if I install DB in RAID 5 or multiple regular disk.

Generally speaking, RAID 5 (or it's successor RAID S) will give good performance if your DB is primarily read only. RAID 5 will be a real pain in the butt for you performance wise if your DB is write intensive, especially if you perform many small write I/O's.

This is due to the fact that RAID 5/S needs to read and write not just the entire data block being written, but also the entire parity block - even if your are writing only a small fragment of data! (< a block's worth).

Read I/O's are not as bad as writes. Reads seem to perform 2 - 3 times faster than writes.

RAID 0 or RAID 0+1 is a far superior configuration - if your budget will allow for the extra hardware necessary to implement it.

My Oracle environment was initially configured using a large EMC array set up under RAID 5. At first, things weren't too bad. However, as data volumes and user loads increased, it became necessary to reconfigure the array as RAID 0+1. I/O performance increased by 5 to 10 times!

In article <374217FF.E929065C_at_umich.edu>,   Peizhong Wu <wupz_at_umich.edu> wrote:
> Hi,
>
> Our group is trying to get a new Sun StorEdge A1000 ( 144GB, RAID5).
Is
> anyone know the performance?
>
> Thanks
>
>

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