It's very possible, but I don't know how to tell. Is there an easy way to know if the sync() calls are taking inordinately long?
Mark Thomas Briggs wrote: > Is the sync necessary to commit a transaction slow? Performance of > that sync depends on the OS, file system, hardwar, etc. IIRC, so IOs > may be fast but it's possible that the syncs are killing you. > > -T > > On Tue, Sep 22, 2009 at 5:14 PM, Mark <godef...@gmail.com> wrote: >> Lothar Scholz wrote: >>> Hello Mark, >>> >>> Tuesday, September 22, 2009, 3:53:48 AM, you wrote: >>> >>> M> I've currently got a loaner high-performance flash-based "SSD" (let's >>> M> just say it doesn't connect to any disk controllers) that I'm testing >>> M> for performance. I've run my application against it, and I believe that >>> M> I should see numbers MUCH higher than I do. When I run my test app on a >>> M> normal SATA 7200 RPM disk, I get a certain performance, and on the "SSD" >>> M> I get about 1/10th that speed. On an array of SAS disks I get numbers >>> M> that are about 5x faster than my SATA disk, so my software itself isn't >>> M> (I believe) the bottleneck. >>> >>> M> I'm wondering if anyone has any tips for "optimizing" for this sort of >>> M> storage solution. >>> >>> Throw it into the trash bin and buy a new one which has a 3rd >>> generation controller and at least 64MB fast cache. The old JMicron >>> controller that many low cost SSD still use was developed for Flash >>> USB sticks. >>> >>> With modern SSD like the latest Samsung should give you at least the >>> same performance as the SATA. If it gets better depends on file size >>> and cache. Are you sure that the SAS RAID Controller is not keeping >>> everything in the controller cache? >> This isn't an "SSD". It's connected directly to the PCI Express bus, and >> "low cost" it certainly is NOT. It's much more valuable than the server >> it's plugged into. >> >> I've run benchmark tests (iometer), and the benchmarks show it's as fast >> as the mfgr says it should be (~700MB/sec read and write bandwidth, >> >115,000 IOPS) but it performs quite poorly when I run my app on it. I >> can't figure out why. >> >> Mark _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
