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Hi Zang,

As JuanFra points out there's not much sense in using Swift on top of raid
as swift handel; extending on this RAID introduces a "write penalty" (
http://theithollow.com/2012/03/21/understanding-raid-penalty/) this in turn
leads to performance issues, refer the link for write penalty's per
configuration.

As I recall (though this was from way back in October 2010) the suggested
method of deploying swift is onto standalone XFS drives, leaving swift to
handel the replication and distribution.


Cheers

David






On Wed, Dec 19, 2012 at 9:12 AM, JuanFra Rodriguez Cardoso <
juanfra.rodriguez.cardoso at gmail.com> wrote:

> Hi Zang:
>
> Basically, it makes no sense to use Swift on top of RAID because Swift
> just delivers replication schema.
>
> Regards,
> JuanFra.
>
> 2012/12/19 Hua ZZ Zhang <zhuadl at cn.ibm.com>
>
>> Hi,
>>
>> I have read the admin document of Swift and find there's recommendation
>> of not using RAID 5 or 6 because swift performance degrades quickly with it.
>> Can anyone explain why this could happen? If the RAID is done by hardware
>> RAID controller, will the performance issue still exist?
>> Anyone can share such kind of experience of using RAID with Swift?
>> Appreciated for any suggestion from you.
>>
>> -Zhang Hua
>>
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