Re: [PERFORM] SSD and RAID

2012-03-07 Thread Andrea Suisani
On 03/06/2012 10:34 AM, Yeb Havinga wrote: On 2012-03-06 09:34, Andrea Suisani wrote: On 03/06/2012 09:17 AM, Yeb Havinga wrote: PS: we applied the same philosophy (different brands) also to motherboards, io controllers and memory, but after testing, we liked one IO controllers software so m

Re: [PERFORM] SSD and RAID

2012-03-07 Thread Andrea Suisani
On 03/06/2012 09:17 AM, Yeb Havinga wrote: On 2012-03-05 23:37, Mark Kirkwood wrote: Which brings up the question of should it be a pair in RAID 1 or just a singe drive? Traditionally this would have been a no brainer "Of course you want RAID 1 or RAID 10"! However our experience with SSD fail

Re: [PERFORM] SSD and RAID

2012-03-07 Thread Yeb Havinga
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 Post

Re: [PERFORM] SSD and RAID

2012-03-06 Thread Mark Kirkwood
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.p

Re: [PERFORM] SSD and RAID

2012-03-06 Thread Yeb Havinga
On 2012-03-06 09:34, Andrea Suisani wrote: On 03/06/2012 09:17 AM, Yeb Havinga wrote: PS: we applied the same philosophy (different brands) also to motherboards, io controllers and memory, but after testing, we liked one IO controllers software so much more than the other so we chose to have

Re: [PERFORM] SSD and RAID

2012-03-06 Thread Yeb Havinga
On 2012-03-05 23:37, Mark Kirkwood wrote: Which brings up the question of should it be a pair in RAID 1 or just a singe drive? Traditionally this would have been a no brainer "Of course you want RAID 1 or RAID 10"! However our experience with SSD failure modes points to firmware bugs as primary

Re: [PERFORM] SSD and RAID

2012-03-05 Thread Tomas Vondra
Hi, a few personal opinions (your mileage may wary ...) On 5.3.2012 23:37, Mark Kirkwood wrote: > Where I work we are starting to look at using SSDs for database server > storage. Despite the higher per unit cost it is quite attractive to > replace 6-8 SAS drives in RAID 10 by a pair of SSD in RAI