Am 23.01.2015 um 20:43 schrieb Robert Mustacchi via smartos-discuss: > On 1/23/15 8:56 , InterNetX - Juergen Gotteswinter via smartos-discuss > wrote: >> Hello SmartOS List, >> >> in the latest SmartOS Build release-20150122-20150122T063410Z suddenly >> appeared serious disk performance decrease, and which is even worse, i/o >> errors inside the kvm instances. this happens with self installed kvm >> instances from iso images as well as with preinstalled images from >> joyent. guest os doesnt matter, too. we tried ubuntu, debian, centos and >> freebsd guests. >> >> Reverting to the 20150108 Build fixed it, so there must be something >> changed in this timeframe which isnt that good. Anyone got an idea which >> commit could cause this? >> >> This effects appeared on different plattforms (dell r410, supermicro >> systems), so its very unlikely that its caused by hardware issues. > > The integration of illumos #4923 want preadv and pwritev uncovered an > existing bug in QEMU. Basically, QEMU uses preadv and pwritev but > doesn't bother to check IOV_MAX and therefore was performing I/O that > was causing an error to be set. You can read the full details here: > https://smartos.org/bugview/HVM-815. We've also filed a follow up RFE to > increase IOV_MAX.
Something strange in Qemu was my last guess, uneducated guess (non-dev here). Nice to hear that the root cause is already known and fixed. > > At this time, we've backported the change to the release branches and > are respinning the SDC release and likely the SmartOS release. We'll > keep you posted. Great! Thanks to both of you (and joyent of course) for your ultra quick response & solution! > > Robert > > > ------------------------------------------- > smartos-discuss > Archives: https://www.listbox.com/member/archive/184463/=now > RSS Feed: https://www.listbox.com/member/archive/rss/184463/26910370-9cc4a721 > Modify Your Subscription: https://www.listbox.com/member/?&; > Powered by Listbox: http://www.listbox.com > ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
