Re: SSD and RAID

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