Having a problem here where, if I write quickly in a domU, dom0 freezes up and I cant do anything but reboot, you can still type, just nothing will ever do anything. I noticed that I am able to get much faster speeds writing in the domU then in dom0: dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/s I do not get the freeze/lockup when writing in dom0, only when writing quickly a lot of data in domU. I am using file: for my vm''s , using the 2.6.32.27 dom0 from git. Any help would be great! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Rudi Ahlers
2011-Feb-18 11:06 UTC
Re: [Xen-users] Writing fast in domU crashes entire xen system
On Fri, Feb 18, 2011 at 12:58 PM, moncojhr <moncojhr@gmail.com> wrote:> Having a problem here where, if I write quickly in a domU, dom0 > freezes up and I cant do anything but reboot, you can still type, just > nothing will ever do anything. > > I noticed that I am able to get much faster speeds writing in the domU > then in dom0: > > dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s > domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/s > > I do not get the freeze/lockup when writing in dom0, only when writing > quickly a lot of data in domU. > > I am using file: for my vm''s , using the 2.6.32.27 dom0 from git. > > Any help would be great! > > _______________________________________________It sounds like your domU doesn''t have enough RAM so it has to use a lot of swap, which causes an I/O overload problem. Assign more RAM to the domU and see if it helps. -- Kind Regards Rudi Ahlers SoftDux Website: http://www.SoftDux.com Technical Blog: http://Blog.SoftDux.com Office: 087 805 9573 Cell: 082 554 7532 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
moncojhr
2011-Feb-18 11:55 UTC
Re: [Xen-users] Writing fast in domU crashes entire xen system
well I gave the vm more ram, and it didnt make any difference, my test to see if it blows everything up is simply: dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 dd if=/dev/zero of=/test bs=1024 count=1048576 it always "crashes" before it completes all the dd''s> On Fri, Feb 18, 2011 at 10:06 PM, Rudi Ahlers <Rudi@softdux.com> wrote: >> On Fri, Feb 18, 2011 at 12:58 PM, moncojhr <moncojhr@gmail.com> wrote: >>> Having a problem here where, if I write quickly in a domU, dom0 >>> freezes up and I cant do anything but reboot, you can still type, just >>> nothing will ever do anything. >>> >>> I noticed that I am able to get much faster speeds writing in the domU >>> then in dom0: >>> >>> dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s >>> domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/s >>> >>> I do not get the freeze/lockup when writing in dom0, only when writing >>> quickly a lot of data in domU. >>> >>> I am using file: for my vm''s , using the 2.6.32.27 dom0 from git. >>> >>> Any help would be great! >>> >>> _______________________________________________ >> >> >> >> It sounds like your domU doesn''t have enough RAM so it has to use a >> lot of swap, which causes an I/O overload problem. >> >> Assign more RAM to the domU and see if it helps. >> >> >> -- >> Kind Regards >> Rudi Ahlers >> SoftDux >> >> Website: http://www.SoftDux.com >> Technical Blog: http://Blog.SoftDux.com >> Office: 087 805 9573 >> Cell: 082 554 7532 >> >> _______________________________________________ >> Xen-users mailing list >> Xen-users@lists.xensource.com >> http://lists.xensource.com/xen-users >> >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Fajar A. Nugraha
2011-Feb-18 11:55 UTC
Re: [Xen-users] Writing fast in domU crashes entire xen system
On Fri, Feb 18, 2011 at 5:58 PM, moncojhr <moncojhr@gmail.com> wrote:> Having a problem here where, if I write quickly in a domU, dom0 > freezes up and I cant do anything but reboot, you can still type, just > nothing will ever do anything. > > I noticed that I am able to get much faster speeds writing in the domU > then in dom0: > > dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s > domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/sThat''s because dom0 is buffering the writes.> > I do not get the freeze/lockup when writing in dom0, only when writing > quickly a lot of data in domU. > > I am using file: for my vm''s , using the 2.6.32.27 dom0 from git.Don''t use file:. Use: - tap2:tapdisk:aio: (if you''re using Xen >= 4.0.1) - tap:tapdisk:aio: (if you''re using Xen = 4.0.0) - tap:aio (anything older than 4.0.0) -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
moncojhr
2011-Feb-18 12:10 UTC
Re: [Xen-users] Writing fast in domU crashes entire xen system
I thought using blktap might help it, but i''ve been unable to get it to work... booting the kernel i just get eventually: XENBUS: Waiting for devices to initialise: 295s.. then it just fails to boot. In my config: disk = [''tap2:tapdisk:aio:/root/testvm/disks/test.img,xvda1,w''] cat /sys/class/blktap2/devices 0 aio:/root/testvm/disks/test.img looks like it was working? On Fri, Feb 18, 2011 at 10:55 PM, Fajar A. Nugraha <list@fajar.net> wrote:> On Fri, Feb 18, 2011 at 5:58 PM, moncojhr <moncojhr@gmail.com> wrote: >> Having a problem here where, if I write quickly in a domU, dom0 >> freezes up and I cant do anything but reboot, you can still type, just >> nothing will ever do anything. >> >> I noticed that I am able to get much faster speeds writing in the domU >> then in dom0: >> >> dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s >> domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/s > > That''s because dom0 is buffering the writes. > >> >> I do not get the freeze/lockup when writing in dom0, only when writing >> quickly a lot of data in domU. >> >> I am using file: for my vm''s , using the 2.6.32.27 dom0 from git. > > Don''t use file:. > Use: > - tap2:tapdisk:aio: (if you''re using Xen >= 4.0.1) > - tap:tapdisk:aio: (if you''re using Xen = 4.0.0) > - tap:aio (anything older than 4.0.0) > > -- > Fajar >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Fajar A. Nugraha
2011-Feb-18 12:52 UTC
Re: [Xen-users] Writing fast in domU crashes entire xen system
On Fri, Feb 18, 2011 at 7:10 PM, moncojhr <moncojhr@gmail.com> wrote:> I thought using blktap might help it, but i''ve been unable to get it to work... > > booting the kernel i just get eventually: > > XENBUS: Waiting for devices to initialise: 295s.. then it just fails to boot. > > In my config: > > disk = [''tap2:tapdisk:aio:/root/testvm/disks/test.img,xvda1,w''] > > cat /sys/class/blktap2/devices > 0 aio:/root/testvm/disks/test.img > > looks like it was working?It works fine for me. You can try testing it manually first (see http://lxr.xensource.com/lxr/source/tools/blktap2/README, find "tapdisk2 -n"). If it works, you should be able to mount the device (shown after you run the command) on dom0. If it doesn''t work, you can try tap:aio, which should work for all Xen versions (and still better than file:) -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users