On 09/11/2011 09:21 AM, Igor Chudov wrote:
On Sun, Sep 11, 2011 at 9:16 AM, Claudio Freire <klaussfreire@xxxxxxxxx <mailto:klaussfreire@xxxxxxxxx>> wrote: On Sun, Sep 11, 2011 at 3:59 PM, Igor Chudov <ichudov@xxxxxxxxx <mailto:ichudov@xxxxxxxxx>> wrote: > Well, right now, my server has twelve 7,200 RPM 2TB hard drives in a RAID-6 > configuration. > They are managed by a 3WARE 9750 RAID CARD. > > I would say that I am not very concerned with linear relationship of read > speed to disk speed. If that stuff is somewhat slow, it is OK with me. With Raid 6 you'll have abysmal performance on write operations. In data warehousing, there's lots of writes to temporary files, for sorting and stuff like that. You should either migrate to raid 10, or set up a separate array for temporary files, perhaps raid 0. Thanks. I will rebuild the RAID array early next week and I will see if I have a Raid 10 option with that card. Quantitatively, what would you say is the write speed difference between RAID 10 and RAID 6?
Note that using RAID 10, while faster, cuts your usable space in half. 12 2TB drives in raid 10 == 6 drives * 2TB == 12 TB total space. That's not big enough, is it? -Andy -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
