Re: [Xen-users] Migration stalls with 2.6.26.5 kernel

["Nemeth, Tamas" <nice@xxxxxxxxxxxxxxx>]

ïHi!

Migrating, save, restore, etc. are scheduled for 2.6.27. Balloning is
also broken in early 2.6.26. I don't know if it is still broken. Even
using more than one vcpu makes most domU kernels unrelianbe. The only
reliable and fully-supported kernels seem to be the original xen.org
kernels (2.8.18.8) both as dom0 and domU. I've had a lot of struggle
related to tis topic.

Cheers:

Tamas

PS:

Take a look at the archives of the xen-devel mailing list at
around ïTue, 22 Jul 2008 18:11:26 -0600!        Thread: [Xen-devel] PROBLEM:
Xen ballon driver seems to be broken 


2008. 09. 18, csÃtÃrtÃk keltezÃssel 15.55-kor Trevor Bentley ezt Ãrta:
> Hello,
> 
> I have been struggling through the task of moving our infrastructure 
> over to Xen VMs.  We were initially using Ubuntu packages for both dom0 
> and our domUs, but experienced extreme instability so we moved to 
> CentOS, which has been much more reliable for dom0.   Since we already 
> had a bunch of Ubuntu VMs, we left them using the Ubuntu 2.4.24-19-xen 
> kernel, but this has turned out to be a mistake -- we get frequent 
> kernel oopses during heavy disk I/O.  We modified the kernel to add 
> NFS-root support, but that is the only change we made to the original 
> config.  All of our domUs mount their root file systems over NFS.
> 
> My problem is that I tried to upgrade the domU kernels to the latest 
> kernel.org stable release (2.6.26.5) and did manage to get it working 
> after some initial trouble (TCP checksum offloading was breaking NFS).  
> However, the new kernel will not live migrate anymore.  When I execute 
> the live migrate command:
> 
> # xm migrate --live testvm 192.168.1.20
> 
> Migration hangs forever.  The VM changes name to "migrate-testvm" and 
> keeps running normally on the system it was on, and appears as "testvm" 
> with state "-br---" on the destination machine with 0 CPU time.  I left 
> tcpdump running on the destination machine and captured an 84MB pcap 
> file which looked pretty normal up until all traffic just completely 
> stopped.  If I just change the "kernel=" line in the config script to 
> the Ubuntu kernel migration works again.
> 
> Here's my VM configuration:
> -------------------                                  
> name        = 'testvm'
> kernel      = '/xen_vm/global/kernels/vmlinuz-2.6.26.5'
> ramdisk     = '/xen_vm/global/kernels/initrd.img-xen-latest'
> memory      = '256'
> disk        = ['tap:aio:/xen_vm/global/swaps/testvm.img,xvda1,w']
> vif         = [
>                 'mac=00:16:3e:5b:8d:5d,bridge=xenbr0',
>                 'mac=00:16:3e:99:9b:e7,bridge=xenbr1'
>               ]
> on_poweroff = 'destroy'
> on_reboot   = 'restart'
> on_crash    = 'restart'
> extra       = '2 console=hvc0 root=/dev/nfs ip=:192.168.1.12::::eth1:'
> nfs_server  = '192.168.1.12'
> nfs_root    = '/xen_vm/testvm'
> -------------------
> 
> 
> xend.log on source:
> -------------------
> [2008-09-18 15:51:11 xend 3751] DEBUG (balloon:127) Balloon: 786956 KiB 
> free; need 2048; done.
> [2008-09-18 15:51:11 xend 3751] DEBUG (XendCheckpoint:89) [xc_save]: 
> /usr/lib/xen/bin/xc_save 33 38 0 0 1
> -------------------
> 
> xend.log on destination:
> -------------------
> ...
> [2008-09-18 15:51:11 xend.XendDomainInfo 3331] DEBUG 
> (XendDomainInfo:1350) XendDomainInfo.construct: None
> [2008-09-18 15:51:11 xend 3331] DEBUG (balloon:127) Balloon: 262832 KiB 
> free; need 2048; done.
> ...
> [2008-09-18 15:51:11 xend 3331] DEBUG (blkif:24) exception looking up 
> device number for xvda1: [Errno 2] No such file or directory: '/dev/xvda1'
> [2008-09-18 15:51:11 xend 3331] DEBUG (DevController:110) DevController: 
> writing {'backend-id': '0', 'virtual-device': '51713', 'device-type': 
> 'disk', 'state': '1', 'backend': '/local/domain/0/backend/tap/10/51713'} 
> to /local/domain/10/device/vbd/51713.
> ...
> [2008-09-18 15:51:12 xend 3331] DEBUG (XendCheckpoint:198) 
> restore:shadow=0x0, _static_max=0x100, _static_min=0x100,
> [2008-09-18 15:51:12 xend 3331] DEBUG (balloon:127) Balloon: 262832 KiB 
> free; need 262144; done.
> [2008-09-18 15:51:12 xend 3331] DEBUG (XendCheckpoint:215) [xc_restore]: 
> /usr/lib/xen/bin/xc_restore 24 10 1 2 0 0 0
> -------------------
> 
> 
> Xen version: xen-3.0-x86_32p
> dom0: 2.6.18-92.1.10.el5xen
> 
> Anybody know what would cause this, or have any suggestions for tracking 
> down the problem?  I did find a post from someone who was seeing 
> identical behavior who claimed he fixed it by enabling CPU Hotplug 
> support, but I already have that enabled in the kernel.
> 
> Thanks,
> 
> Trevor
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users