On Wed, Feb 19, 2014 at 8:13 AM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: > On Tue, Feb 18, 2014 at 2:41 PM, Tomas Vondra <tv@xxxxxxxx> wrote: >> On 18.2.2014 02:23, KONDO Mitsumasa wrote: >>> Hi, >>> >>> I don't have PERC H710 raid controller, but I think he would like to >>> know raid striping/chunk size or read/write cache ratio in >>> writeback-cache setting is the best. I'd like to know it, too:) >> >> We do have dozens of H710 controllers, but not with SSDs. I've been >> unable to find reliable answers how it handles TRIM, and how that works >> with wearout reporting (using SMART). > > AFAIK (I haven't looked for a few months), they don't support TRIM. > The only hardware RAID vendor that has even basic TRIM support Intel > and that's no accident; I have a theory that enterprise storage > vendors are deliberately holding back SSD: SSD (at least, the newer, > better ones) destroy the business model for "enterprise storage > equipment" in a large percentage of applications. A 2u server with, > say, 10 s3700 drives gives *far* superior performance to most SANs > that cost under 100k$. For about 1/10th of the price. > > If you have a server that is i/o constrained as opposed to storage > constrained (AKA: a database) hard drives make zero economic sense. > If your vendor is jerking you around by charging large multiples of > market rates for storage and/or disallowing drives that actually > perform well in their storage gear, choose a new vendor. And consider > using software raid. You can also do the old trick of underprovisioning and / or underutilizing all the space on SSDs. I.e. put 10 600GB SSDs under a HW RAID controller in RAID-10, then only parititon out 1/2 the storage you get from that. so you get 1.5TB os storage and the drives are underutilized enough to have spare space. Right now I'm testing on a machine with 2x Intel E5-2690s (http://ark.intel.com/products/64596/intel-xeon-processor-e5-2690-20m-cache-2_90-ghz-8_00-gts-intel-qpi) 512GB RAM and 6x600GB Intel SSDs (not sure which ones) under a LSI MegaRAID 9266. I'm able to crank out 6500 to 7200 TPS under pgbench on a scale 1000 db at 8 to 60 clients on that machine. It's not cheap, but storage wise it's WAY cheaper than most SANS and very fast. pg_xlog is on a pair of non-descript SATA spinners btw. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
