I'm just trying the delaylog mount option on a filesystem (LVM over 2x 2TB 4K sector drives), and I see this while running 8 processes of "rm -r * & 2>/dev/null": Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sdc 2,80 33,40 125,00 64,60 720,00 939,30 17,50 0,55 2,91 1,71 32,40 sdd 0,00 25,60 122,80 63,40 662,40 874,40 16,51 0,52 2,77 1,96 36,54 dm-0 0,00 0,00 250,60 123,00 1382,40 1941,70 17,79 1,64 4,39 1,74 65,08 Then I issue "sync", and utilisation increases: Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sdc 0,00 0,20 15,80 175,40 84,00 2093,30 22,78 0,62 3,26 2,93 55,94 sdd 0,00 1,00 13,40 177,60 79,20 2114,10 22,97 0,69 3,63 3,34 63,80 dm-0 0,00 0,00 29,20 101,20 163,20 4207,40 67,03 1,11 8,51 7,56 98,60 This is reproducible. Now it can be that the sync just causes more writes and stalls reads so overall it's slower, but I'm wondering why none of the devices says "100% util", which should be the case on deletes? Or is this again the "mistake" of the utilization calculation that writes do not really show up there? I know I should have benchmarked and tested, I just wanted to raise eyes on this as it could be possible there's something to optimize. Another strange thing: After the 8 "rm -r" finished, there were some subdirs left over that hadn't been deleted - running one "rm -r" cleaned them out then. Could that be a problem with "delaylog"? Or can that happen when several "rm" compete in the same dirs? This is kernel 2.6.35.4 -- mit freundlichen Grüssen, Michael Monnerie, Ing. BSc it-management Internet Services http://proteger.at [gesprochen: Prot-e-schee] Tel: 0660 / 415 65 31 ****** Aktuelles Radiointerview! ****** http://www.it-podcast.at/aktuelle-sendung.html // Wir haben im Moment zwei Häuser zu verkaufen: // http://zmi.at/langegg/ // http://zmi.at/haus2009/
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