Red Hat Bugzilla – Bug 586387
Xen tap:aio fails on XFS filesystem (but works on ext3)
Last modified: 2010-05-24 11:12:09 EDT
Description of problem: When creating a vm using virt-install on CentOS 5.4, if the file system image is stored on an XFS filesystem, various read/write and IO errors occur in the DomU guest. Moving the same file to an ext3 partition works. This may or may not be related to: https://bugzilla.redhat.com/show_bug.cgi?id=217098 Version-Release number of selected component (if applicable): kernel-xen-2.6.18-164.15.1.el5 xen-3.0.3-94.el5_4.3 How reproducible: Always. Steps to Reproduce: 1. Create an XFS filesytem (mine is 3 x 1Tb SATA drives in mdraid5) 2. Use virt-install to create a Xen guest file on the XFS filesystem 3. Try to install any guest OS. Actual results: IO errors, read / write errors and more. Expected results: Expected that as long as Dom0 can see the file and read it correctly, then the DomU should too! Additional info: A workaround seems to be setting the xen config file line from: disk = [ "tap:aio:/vm-images/mail.crc.id.au.img,xvda,w" ] to: disk = [ "file:/vm-images/mail.crc.id.au.img,xvda,w" ] However this incurs a severe performance penalty.
xfs-kmod isn't supported ... are you using that, or the xfs.ko that comes with RHEL^w^w^w^wCentos5.4? If you're using the old centos xfs kmod, it's a) not a red hat bug, and b) a bad idea ;) if you're using the xfs.ko from the stock kernel, then an actual list of the "IO errors, read / write errors and more." would be most helpful. -Eric
Hi Eric, I am using the stock kernel for CentOS 5.4 - I have not installed any kmod for XFS support. $ rpm -qa | grep xfs xfsprogs-2.9.4-1.el5.centos $ rpm -qa | grep kmod kmod-e1000e-xen-1.1.2.1a_NAPI-1.el5.elrepo I have the e1000e kmod installed as the stock module for this NIC only brings it up at 100FD instead of 1000FD. I have since updated this machine to 5.5 and will attempt to retest this issue shortly. The kernel on this machine now is: kernel-xen-2.6.18-164.15.1.el5 Marking as need more info from me for now.
There weren't a lot of changes in xfs from 5.4 to 5.5, but testing 5.5 would be welcome in any case. Again, including details on the errors you saw would be great. Thanks, -Eric
/mnt/raid is a 1Tb XFS filesystem: /dev/mapper/RAID5-fileshare on /mnt/raid type xfs (rw) # virt-install -p --prompt What is the name of your virtual machine? test How much RAM should be allocated (in megabytes)? 512 What would you like to use as the disk (file path)? /mnt/raid/test.img How large would you like the disk (/mnt/raid/test.img) to be (in gigabytes)? 2 What is the install URL? ftp://localhost/centos Starting install... <snip> When starting the install, xenblk loads as it should, go through the prompts and select VNC installation. Interestingly this didn't throw an error. I am just about to rebuild the Dom0 machine for this however - so I will double check everything with a stock 5.5 install before posting anything further. At this stage, it may not be reproducible with 5.5.
Unable to reproduce in 5.5. I'm happy to close this until I can find a 100% reproducible scenario. (Sadly, I can't mark it as closed! :) )
Ok, thanks for the updates!