On Sep 11, 2011, at 9:21 AM, Igor Chudov wrote:
On Sun, Sep 11, 2011 at 9:16 AM, Claudio Freire <klaussfreire@xxxxxxxxx> wrote:
On Sun, Sep 11, 2011 at 3:59 PM, Igor Chudov < 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.
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?
As someone who migrated a RAID 5 installation to RAID 10, I am getting far better read and write performance on heavy calculation queries. Writing on the RAID 5 really made things crawl. For lots of writing, I think RAID 10 is the best. It should also be noted that I changed my filesystem from ext3 to XFS - this is something you can look into as well.
Ogden
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