Re: Raid Chunk Sizes for DSS type DB - Mailing list pgsql-general

From Hannes Dorbath
Subject Re: Raid Chunk Sizes for DSS type DB
Date
Msg-id 4726ED33.40004@theendofthetunnel.de
Whole thread Raw
In response to Re: Raid Chunk Sizes for DSS type DB  ("Joshua D. Drake" <jd@commandprompt.com>)
List pgsql-general
On 30.10.2007 03:11, Joshua D. Drake wrote:
> Ow Mun Heng <Ow.Mun.Heng@wdc.com> wrote:
>
>> It's not an optimal setup but since I only have 3x500G drives to play
>> with, I can't build a Raid10
>
> Uhhh RAID 1 is your best bet. You get fault tolerance (mirrored) plus
> you get a hot spare (3 drives).

This is not true with Linux MD RAID.

It might sound scary to most people, but you _can_ have a RAID 10 with
only 3 drives.

http://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10

Another thing you want to do is to check if the MD device you created
supports barriers. I know MD RAID 1 does, MD RAID 5 does not, I don't
know about MD RAID 10.

If it does not, make sure you have an UPS.


--
Regards,
Hannes Dorbath

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