Hello, I would like to ask for some help with troubleshooting, A few days ago I installed Debian Squeeze (amd64) with the Xen kernel and Xen 4 (from the Debian repos) on a small computer. I used Xen-tools to create a DomU (also Squeeze/amd64) which is now my e-mail and web server. This is all purely for hobbyist/educational use. Now the problem is that my DomU will occasionally lose all network connectivity. If that happens, it can''t be pinged or anything (no route to host). Also, it leaves no trace as far as I can tell in any of the log files. The network just seems to go out silently. The Dom0 does not seem to be affected. I can SSH into the Dom0 and from there, "xm console myserver" into the DomU. This works well except that there is no network, not even after "/etc/init.d/networking restart". Only after I reboot the DomU, everything seems to be in order again. It may then run for 18 hours without a problem, or fail again within a much shorter time. This seems to be completely random, ie. it doesn''t look like it is related to any heavy network traffic or even CPU load. I tried to use "post-up ethtool -K eth0 tx off" in the /etc/network/interfaces file of the DomU, because the comment says it "might resolve problems for some users." It doesn''t in my case. Because I am quite new to Xen I have no clue about how to troubleshoot this situation. My attempts at googling probably were a little uneducated as well. Any hints would be appreciated. If I need to post log files, configuration files or any command output I will gladly do so as well. I have thought of "downgrading" to Debian Lenny (after all, Squeeze is still the "testing" distro) and Xen 3.2 (I prefer to use whatever version of Xen that Debian offers as packages). But will I be able to just copy my DomU files (images and configuration) over to the "older" version and still use them? Regards, Olav _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Sep 2, 2010 at 3:52 AM, Olav Lavell <olav@lavell.nl> wrote:> A few days ago I installed Debian Squeeze (amd64) with the Xen kernel and > Xen 4 (from the Debian repos) on a small computer. I used Xen-tools to > create a DomU (also Squeeze/amd64) which is now my e-mail and web server. > This is all purely for hobbyist/educational use.> I tried to use "post-up ethtool -K eth0 tx off" in the > /etc/network/interfaces file of the DomU, because the comment says it > "might resolve problems for some users." It doesn''t in my case.try doing it on dom0 as well.> > Because I am quite new to Xen I have no clue about how to troubleshoot > this situation. My attempts at googling probably were a little uneducated > as well. Any hints would be appreciated. If I need to post log files, > configuration files or any command output I will gladly do so as well. > > I have thought of "downgrading" to Debian Lenny (after all, Squeeze is > still the "testing" distro) and Xen 3.2 (I prefer to use whatever version > of Xen that Debian offers as packages).The thing I''m not sure Debian is the "best" distro for people like you, who like to use the distro''s packages and would like it to "just work". I''d actually recommend you simply use Centos5. Others on this list have suggested Opensuse 11.3, but with updated kernel from opensuse kotd. Or even Fedora 13, with third-party RPMs. If you''re willing to compile from source, you can use latest Xen and pv_ops kernel. See http://wiki.xensource.com/xenwiki/Xen4.0 , tutorials section in particular.> But will I be able to just copy my > DomU files (images and configuration) over to the "older" version and still > use them?Should be possible, regardles of what your dom0 distro is. -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, 2 Sep 2010 07:23:15 +0700, "Fajar A. Nugraha" <fajar@fajar.net> wrote:> On Thu, Sep 2, 2010 at 3:52 AM, Olav Lavell <olav@lavell.nl> wrote:[..]>> I tried to use "post-up ethtool -K eth0 tx off" in the >> /etc/network/interfaces file of the DomU, because the comment says it >> "might resolve problems for some users." It doesn''t in my case. > > try doing it on dom0 as well.Thank you, Fajar, for your suggestion. This will have to wait until the weekend when I have more time and physical access to the computer. I just tried it earlier this afternoon but it took the Dom0 a much longer time to boot and bring up the network. Not sure what was going on so I undid the change as quickly as I got access again. Just to be clear, should I apply the ethtool-command to the eth0 interface or to the peth0 and/or vif1.0 on the Dom0?>> Because I am quite new to Xen I have no clue about how to troubleshoot >> this situation. My attempts at googling probably were a littleuneducated>> as well. Any hints would be appreciated. If I need to post log files, >> configuration files or any command output I will gladly do so as well. >> >> I have thought of "downgrading" to Debian Lenny (after all, Squeeze is >> still the "testing" distro) and Xen 3.2 (I prefer to use whateverversion>> of Xen that Debian offers as packages). > > The thing I''m not sure Debian is the "best" distro for people like > you, who like to use the distro''s packages and would like it to "just > work". I''d actually recommend you simply use Centos5. Others on this > list have suggested Opensuse 11.3, but with updated kernel from > opensuse kotd. Or even Fedora 13, with third-party RPMs.Why, exactly? I am comfortable with Debian in general. It''s just Xen that I need to become more familiar with (I''m on my way, if just slowly). But if there is something inherently broken in Debian''s Xen I would like to know of course.> If you''re willing to compile from source, you can use latest Xen and > pv_ops kernel. See http://wiki.xensource.com/xenwiki/Xen4.0 , > tutorials section in particular.I would rather not, too lazy to manage updates etc.>> But will I be able to just copy my >> DomU files (images and configuration) over to the "older" version and >> still use them? > > Should be possible, regardles of what your dom0 distro is.OK, thanks. I worried perhaps Xen 4 uses different image formats or something. It is good to know I have the option of downgrading. I understand Debian Lenny + Xen 3 is a tried and tested combination that shouldn''g give me too much trouble. Meanwhile, to keep my server going I made a little monitoring script that executes every 5 minutes from cron on the Dom0. It pings the DomU and when it doesn''t get a reply, writes a line to a log file and reboots the whole machine. Ugly but effective. -- Olav Lavell <olav@lavell.nl> _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Fri, Sep 3, 2010 at 2:17 AM, Olav Lavell <olav@lavell.nl> wrote:> Just to be clear, should I apply the ethtool-command to the eth0 interface > or to the peth0 and/or vif1.0 on the Dom0?haven''t done that in a while, so I forgot the details. Should be peth0, and (probably) eth0.>> The thing I''m not sure Debian is the "best" distro for people like >> you, who like to use the distro''s packages and would like it to "just >> work". I''d actually recommend you simply use Centos5. Others on this >> list have suggested Opensuse 11.3, but with updated kernel from >> opensuse kotd. Or even Fedora 13, with third-party RPMs. > > Why, exactly? I am comfortable with Debian in general. It''s just Xen that > I need to become more familiar with (I''m on my way, if just slowly). But if > there is something inherently broken in Debian''s Xen I would like to know > of course.Debian is using pv_ops kernel version. Which is good, in a way, since that''s where upstream Xen developers are concentrating their efforts on. But that also means big changes, which leads to possible bugs. Apparently you got one of them. CMIIW, I don''t think Debian guys by themselves are doing much to fix xen-related bugs, relying on upstream. Novell (Opensuse and SLE) uses the old xenfied linux version, forward-ported to newer kernels. Andrew Lyon picked xen-related changes from Novell''s kernel and make it available as a patch for vanilla kernel on http://code.google.com/p/gentoo-xen-kernel/downloads/list . I''ve had better luck with this kernel version, and currently using it on dev environment. RHEL5 uses an "old" version of Xen and kernel, but they actively maintain it with bug/security fixes, so it''s been very stable. So from bugs/stability point of view, I''d really recommend using RHEL/Centos and their built-in Xen version, with Novell''s kernel as an alternative if you need newer kernel version.> >> If you''re willing to compile from source, you can use latest Xen and >> pv_ops kernel. See http://wiki.xensource.com/xenwiki/Xen4.0 , >> tutorials section in particular. > > I would rather not, too lazy to manage updates etc.... which is another reason why I think you''d be better of using RHEL/Centos.> >>> But will I be able to just copy my >>> DomU files (images and configuration) over to the "older" version and >>> still use them? >> >> Should be possible, regardles of what your dom0 distro is. > > OK, thanks. I worried perhaps Xen 4 uses different image formats or > something. It is good to know I have the option of downgrading. I > understand Debian Lenny + Xen 3 is a tried and tested combination that > shouldn''g give me too much trouble.Newer versions of libvirt uses xend-managed config file by default (which is in sxp format), but they can read old-style config just fine. And you can convert sxp-style config to old-style config file (for easier reading, if you want) easily with the help of virsh. There might be some difference in default bridge name, but that can quickly be edited on domU config file.> > Meanwhile, to keep my server going I made a little monitoring script that > executes every 5 minutes from cron on the Dom0. It pings the DomU and when > it doesn''t get a reply, writes a line to a log file and reboots the whole > machine. Ugly but effective.If you''re willing to reboot the whole machine just to make it work, then I highly suggest you spend some time to at least compiling your own kernel with xen patches above. If it works for you, then at least you still get to keep Debian (only changing the kernel). -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users