Date: Thu, 05 Mar 2015 15:10:17 +0100 From: Robert Schulze <rs@bytecamp.net> To: freebsd-geom@freebsd.org Subject: Re: Trim on gmirrored SSDs is slow and results in inresponsive system Message-ID: <54F863C9.3070002@bytecamp.net> In-Reply-To: <54F72E39.2070105@multiplay.co.uk> References: <54F6FE2E.60303@bytecamp.net> <54F707CC.6070105@multiplay.co.uk> <54F7147F.8070206@bytecamp.net> <54F718D9.1080201@multiplay.co.uk> <54F721BC.5070204@bytecamp.net> <54F72E39.2070105@multiplay.co.uk>
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Hi, Am 04.03.2015 um 17:09 schrieb Steven Hartland: > Transaction sizes look like they are the same but the tps from gmirror > is significantly lower. > > As iostat doesn't properly understand deletes it would still be nice to > see that gstat -d -p output as that will also give us queue depth. Since gstat doesnt just output row by row, I had to screenshot a running gstat and transcribe the values. Running gstat -b in a loop doesn't help here, since the system is inresponsive and won't start any program in time during the DELETE ops. So after deleting a 2GB file on a gmirror with two active SSDs I get: # gstat -dpfada -I3s dT: 3.189s w: 3.000s filter: ada L(q) ops/s r/s kBps ms/r w/s kBps ms/w d/s kBps ms/d %busy Name 0 3342 0 0 0.0 0 0 0.0 3342 106939 10.2 80.5| ada0 0 3342 0 0 0.0 0 0 0.0 3342 106939 10.0 82.0| ada1 9 2606 0 0 0.0 0 0 0.0 2606 83400 60.8 98.3| ada0 9 2606 0 0 0.0 0 0 0.0 2606 83400 56.9 98.7| ada1 46 1705 0 0 0.0 0 0 0.0 1705 54565 62.5 98.4| ada0 51 1704 0 0 0.0 0 0 0.0 1704 54512 62.9 97.6| ada1 22 1540 0 0 0.0 0 0 0.0 1540 49285 20.9 96.6| ada0 24 1541 0 0 0.0 0 0 0.0 1541 49317 21.8 96.0| ada1 2 1496 0 0 0.0 0 0 0.0 1496 47887 13.3 98.6| ada0 7 1495 0 0 0.0 0 0 0.0 1495 47855 14.1 98.9| ada1 11 1032 0 0 0.0 0 0 0.0 1032 33010 18.2 98.8| ada0 10 1033 0 0 0.0 0 0 0.0 1033 33070 15.4 98.1| ada1 12 775 0 0 0.0 0 0 0.0 775 24798 26.2 97.5| ada0 16 773 0 0 0.0 0 0 0.0 773 24746 29.6 98.5| ada1 65 743 0 0 0.0 0 0 0.0 743 23784 25.4 98.8| ada0 59 746 0 0 0.0 0 0 0.0 746 23887 24.4 99.0| ada1 > > Try backing out r268816 and see if that has any impact. could you please explain what you mean by that? regards, Robert Schulzehome | help
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