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. 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. Robert ------------------------------------------- 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
