From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44953) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YfYkd-0005Sm-Bf for qemu-devel@nongnu.org; Tue, 07 Apr 2015 15:01:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YfYkc-0001XS-Aj for qemu-devel@nongnu.org; Tue, 07 Apr 2015 15:01:31 -0400 Date: Tue, 7 Apr 2015 20:01:13 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20150407190112.GD2287@work-vm> References: <5522D4BD.7080805@kamp.de> <5522D57B.3000203@redhat.com> <5522D85D.20907@kamp.de> <5522DA21.1010702@kamp.de> <20150407084303.GA2298@work-vm> <5523F38A.4090305@kamp.de> <20150407152957.GB2287@work-vm> <55242597.1000700@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55242597.1000700@kamp.de> Subject: Re: [Qemu-devel] [Qemu-block] Migration sometimes fails with IDE and Qemu 2.2.1 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: Paolo Bonzini , John Snow , "qemu-devel@nongnu.org" , qemu-block@nongnu.org * Peter Lieven (pl@kamp.de) wrote: > Am 07.04.2015 um 17:29 schrieb Dr. David Alan Gilbert: > > * Peter Lieven (pl@kamp.de) wrote: > >> Hi David, > >> > >> Am 07.04.2015 um 10:43 schrieb Dr. David Alan Gilbert: > >>>>>> Any particular workload or reproducer? > >>>>> Workload is almost zero. I try to figure out if there is a way to trigger it. > >>>>> > >>>>> Maybe playing a role: Machine type is -M pc1.2 and we set -kvmclock as > >>>>> CPU flag since kvmclock seemed to be quite buggy in 2.6.16... > >>>>> > >>>>> Exact cmdline is: > >>>>> /usr/bin/qemu-2.2.1 -enable-kvm -M pc-1.2 -nodefaults -netdev type=tap,id=guest2,script=no,downscript=no,ifname=tap2 -device e1000,netdev=guest2,mac=52:54:00:ff:00:65 -drive format=raw,file=iscsi://172.21.200.53/iqn.2001-05.com.equallogic:4-52aed6-88a7e99a4-d9e00040fdc509a3-XXX-hd0/0,if=ide,cache=writeback,aio=native -serial null -parallel null -m 1024 -smp 2,sockets=1,cores=2,threads=1 -monitor tcp:0:4003,server,nowait -vnc :3 -qmp tcp:0:3003,server,nowait -name 'XXX' -boot order=c,once=dc,menu=off -drive index=2,media=cdrom,if=ide,cache=unsafe,aio=native,readonly=on -k de -incoming tcp:0:5003 -pidfile /var/run/qemu/vm-146.pid -mem-path /hugepages -mem-prealloc -rtc base=utc -usb -usbdevice tablet -no-hpet -vga cirrus -cpu qemu64,-kvmclock > >>>>> > >>>>> Exact kernel is: > >>>>> 2.6.16.46-0.12-smp (i think this is SLES10 or sth.) > >>>>> > >>>>> The machine does not hang. It seems just I/O is hanging. So you can type at the console or ping the system, but no longer login. > >>>>> > >>>>> Thank you, > >>>>> Peter > >>>> Interesting observation: Migrating the vServer again seems to fix to problem (at least in one case I could test just now). > >>>> > >>>> 2.6.8-24-smp is also affected. > >>> How often does it fail - you say 'sometimes' - is it a 1/10 or a 1/1000 ? > >> Its more often than 1/10 I would say. > > OK, that's not too bad - it's the 1/1000 that are really nasty to find. > > In your setup, how easy would it be for you to try : > > with either 2.1 or current head? > > with a newer machine-type? > > without the cdrom? > > Its all possible. I can clone the system and try everything on my test systems. I hope > it reproduces there. Great. I think the order I would go would be: Try head - if it works we know we've already got the fix somewhere Try 2.1 - if it works we know it's something we introduced between 2.1 and 2.2.1 Try a newer machine type - because pc-1.2 probably isn't tested much CDROM at the end. > Has the cdrom the power of taking down the bus? I just know the cdrom migration is a bit lacking and the simpler the test case the better. Dave > > Peter -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK