| From: | Yeb Havinga <yebhavinga(at)gmail(dot)com> |
|---|---|
| To: | Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: SSD and RAID |
| Date: | 2012-03-07 09:45:09 |
| Message-ID: | 4F572E25.1000307@gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On 2012-03-07 01:36, Mark Kirkwood wrote:
> On 06/03/12 21:17, Yeb Havinga wrote:
>>
>>
>> One thing to note is that linux software raid with md doesn't support
>> discard, which might shorten the drive's expected lifetime. To get
>> some numbers I tested the raid 1 of ssd's setup for mediawear under a
>> PostgreSQL load earlier, see
>> http://archives.postgresql.org/pgsql-general/2011-11/msg00141.php
>>
>>
>
> Right, which is a bit of a pain - we are considering either formatting
> the drive with less capacity and using md RAID 1 or else doing the
> mirror in LVM to enable a working discard/trim.
When I measured the write durability without discard on the enterprise
disks, I got numbers that in normal production use would outlive the
lifetime of the servers. It would be interesting to see durability
numbers for the desktop SSDs, even when partitioned to a part of the disk.
regards,
Yeb Havinga
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