Hi, I have a xen guest OS and in which I am trying to copy 3GB of file from one location to another(say from / to /home),at this time I/O of the guest OS is reaching 100% and I/O of the Domain-0 is reaching up to 10 to 12%. How can I solve this issue. Thanks, Chanlinux _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, If you have other guests that eat up CPU, perhaps your guest does not get enough CPU to process all the data that the host is able to transfer. What does "xm top" say about physical CPU usage? Another possible cause may be using a slow backend for guest storage (for instance a file over ntfs-3g mount), or the host being very busy doing something else than I/O. This would cause lower I/O load in the host (with more CPU load on other things), while the guest waits 100% of the time for I/O. Cheers, Radu R. On Mon, 2009-07-06 at 16:57 +0530, chandrashekar wrote:> Hi, > > I have a xen guest OS and in which I am trying to copy 3GB of file > from one location to another(say from / to /home),at this time I/O of > the guest OS is reaching 100% and I/O of the Domain-0 is reaching up > to 10 to 12%. > > How can I solve this issue. > > Thanks, > Chanlinux > _______________________________________________ > 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
Radu, Thanks for the help: As you suggested I checked CPU % and there is no issue in CPU but I think this is issue with memory. Please find the xm top for the same. xentop - 20:35:49 Xen 3.1.2-92.el5 2 domains: 1 running, 1 blocked, 0 paused, 0 crashed, 0 dying, 0 shutdown Mem: 4193636k total, 4193292k used, 344k free CPUs: 8 @ 2333MHz NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) VBDS VBD_OO VBD_RD VBD_WR SSID Domain-0 -----r 23050 0.7 2200640 52.5 no limit n/a 8 4 248 2101165 0 0 0 0 0 guest --b--- 3938 0.0 1945432 46.4 1945600 46.4 1 1 2197321 2803970 0 0 0 0 0 ~ Thanks, Chandru On Mon, Jul 6, 2009 at 8:05 PM, Radu Rendec <radu.rendec@ines.ro> wrote:> Hi, > > If you have other guests that eat up CPU, perhaps your guest does not > get enough CPU to process all the data that the host is able to > transfer. What does "xm top" say about physical CPU usage? > > Another possible cause may be using a slow backend for guest storage > (for instance a file over ntfs-3g mount), or the host being very busy > doing something else than I/O. This would cause lower I/O load in the > host (with more CPU load on other things), while the guest waits 100% of > the time for I/O. > > Cheers, > > Radu R. > > On Mon, 2009-07-06 at 16:57 +0530, chandrashekar wrote: > > Hi, > > > > I have a xen guest OS and in which I am trying to copy 3GB of file > > from one location to another(say from / to /home),at this time I/O of > > the guest OS is reaching 100% and I/O of the Domain-0 is reaching up > > to 10 to 12%. > > > > How can I solve this issue. > > > > Thanks, > > Chanlinux > > _______________________________________________ > > 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
On Mon, 2009-07-06 at 20:40 +0530, chandrashekar wrote:> As you suggested I checked CPU % and there is no issue in CPU but I > think this is issue with memory. > > Please find the xm top for the same. > > > xentop - 20:35:49 Xen 3.1.2-92.el5 > 2 domains: 1 running, 1 blocked, 0 paused, 0 crashed, 0 dying, 0 > shutdown > Mem: 4193636k total, 4193292k used, 344k free CPUs: 8 @ 2333MHz > NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS > NETS NETTX(k) NETRX(k) VBDS VBD_OO VBD_RD VBD_WR SSID > Domain-0 -----r 23050 0.7 2200640 52.5 no limit > n/a 8 4 248 2101165 0 0 0 0 0 > guest --b--- 3938 0.0 1945432 46.4 1945600 46.4 > 1 1 2197321 2803970 0 0 0 0 0Chandru, The memory seems to be (almost) equally splitted between dom0 and the guest, and you have plenty of it. But I think I got the explanation to your issue: domU has only one VCPU, while dom0 has 8 CPUs; since I/O activity is likely not to span across multiple CPUs, you have the following: domU: 1 cpu (of 1) waiting 100% for I/O => 100% overall IOwait dom0: 1 cpu (of 8) waiting 100% for I/0 => 1/8 * 100% overall IOwait I think 1/8 * 100% is exactly your 12% Cheers, Radu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Radu, Is this issue may be bcz of filesystem.............? Thanks, Chandru On Mon, Jul 6, 2009 at 8:56 PM, Radu Rendec <radu.rendec@ines.ro> wrote:> On Mon, 2009-07-06 at 20:40 +0530, chandrashekar wrote: > > As you suggested I checked CPU % and there is no issue in CPU but I > > think this is issue with memory. > > > > Please find the xm top for the same. > > > > > > xentop - 20:35:49 Xen 3.1.2-92.el5 > > 2 domains: 1 running, 1 blocked, 0 paused, 0 crashed, 0 dying, 0 > > shutdown > > Mem: 4193636k total, 4193292k used, 344k free CPUs: 8 @ 2333MHz > > NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS > > NETS NETTX(k) NETRX(k) VBDS VBD_OO VBD_RD VBD_WR SSID > > Domain-0 -----r 23050 0.7 2200640 52.5 no limit > > n/a 8 4 248 2101165 0 0 0 0 0 > > guest --b--- 3938 0.0 1945432 46.4 1945600 46.4 > > 1 1 2197321 2803970 0 0 0 0 0 > > Chandru, > > The memory seems to be (almost) equally splitted between dom0 and the > guest, and you have plenty of it. > > But I think I got the explanation to your issue: > > domU has only one VCPU, while dom0 has 8 CPUs; since I/O activity is > likely not to span across multiple CPUs, you have the following: > > domU: 1 cpu (of 1) waiting 100% for I/O => 100% overall IOwait > dom0: 1 cpu (of 8) waiting 100% for I/0 => 1/8 * 100% overall IOwait > > I think 1/8 * 100% is exactly your 12% > > Cheers, > > Radu > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, 2009-07-06 at 21:07 +0530, chandrashekar wrote:> Radu, > > Is this issue may be bcz of filesystem.............?No. It''s just the way top (and other similar tools) compute cpu usage. In dom0 you have only 1 of 8 cpus working, while in domU you have only one cpu. In dom0 try expanding the cpu usage in the "top" utility by pressing "1". You''ll probably see 1 cpu in 100% and the others idle. Cheers, Radu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Thanks Radu, As you told one CPU is reaching 100% utilization. Thanks, Chandru On Mon, Jul 6, 2009 at 9:19 PM, Radu Rendec <radu.rendec@ines.ro> wrote:> On Mon, 2009-07-06 at 21:07 +0530, chandrashekar wrote: > > Radu, > > > > Is this issue may be bcz of filesystem.............? > > No. It''s just the way top (and other similar tools) compute cpu usage. > In dom0 you have only 1 of 8 cpus working, while in domU you have only > one cpu. > > In dom0 try expanding the cpu usage in the "top" utility by pressing > "1". You''ll probably see 1 cpu in 100% and the others idle. > > Cheers, > > Radu > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users