Re: Testing Sandforce SSD - Mailing list pgsql-performance

On 10-08-04 03:49 PM, Scott Carey wrote:
> On Aug 2, 2010, at 7:26 AM, Merlin Moncure wrote:
>
>> On Fri, Jul 30, 2010 at 11:01 AM, Yeb Havinga<yebhavinga@gmail.com>  wrote:
>>> After a week testing I think I can answer the question above: does it work
>>> like it's supposed to under PostgreSQL?
>>>
>>> YES
>>>
>>> The drive I have tested is the $435,- 50GB OCZ Vertex 2 Pro,
>>> http://www.newegg.com/Product/Product.aspx?Item=N82E16820227534
>>>
>>> * it is safe to mount filesystems with barrier off, since it has a 'supercap
>>> backed cache'. That data is not lost is confirmed by a dozen power switch
>>> off tests while running either diskchecker.pl or pgbench.
>>> * the above implies its also safe to use this SSD with barriers, though that
>>> will perform less, since this drive obeys write trough commands.
>>> * the highest pgbench tps number for the TPC-B test for a scale 300 database
>>> (~5GB) I could get was over 6700. Judging from the iostat average util of
>>> ~40% on the xlog partition, I believe that this number is limited by other
>>> factors than the SSD, like CPU, core count, core MHz, memory size/speed, 8.4
>>> pgbench without threads. Unfortunately I don't have a faster/more core
>>> machines available for testing right now.
>>> * pgbench numbers for a larger than RAM database, read only was over 25000
>>> tps (details are at the end of this post), during which iostat reported
>>> ~18500 read iops and 100% utilization.
>>> * pgbench max reported latencies are 20% of comparable BBWC setups.
>>> * how reliable it is over time, and how it performs over time I cannot say,
>>> since I tested it only for a week.
>> Thank you very much for posting this analysis.  This has IMNSHO the
>> potential to be a game changer.  There are still some unanswered
>> questions in terms of how the drive wears, reliability, errors, and
>> lifespan but 6700 tps off of a single 400$ device with decent fault
>> tolerance is amazing (Intel, consider yourself upstaged).  Ever since
>> the first samsung SSD hit the market I've felt the days of the
>> spinning disk have been numbered.  Being able to build a 100k tps
>> server on relatively inexpensive hardware without an entire rack full
>> of drives is starting to look within reach.
> Intel's next gen 'enterprise' SSD's are due out later this year.  I have heard from those with access to to test
samplesthat they really like them -- these people rejected the previous versions because of the data loss on power
failure.
>
> So, hopefully there will be some interesting competition later this year in the medium price range enterprise ssd
market.
>

I'll be doing some testing on Enterprise grade SSD's this year.  I'll
also be looking at some hybrid storage products that use as  SSD's as
accelerators mixed with lower cost storage.

--
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.