Hello group, does anyone have had any luck with hosting qemu kvm images resided on BTRFS filesystem while serving the volume via iSCSI? I encouraged some unidentified problem and I am able to replicate it. Basically the NTFS filesystem inside RAW image gets corrupted every time when Windows guest boots. What is weired is that changing filesystem for ext4 or xfs solves the issue. The problem replication looks as follows: 1) run chkdsk on the guest to make sure the filesystem structure is in good shape, 2) shut down the VM via libvirtd, 3) rsync changes between source and backup image, 4) generate SHA1 for backup and original and compare it, 5) try to run guest on the backup image, I was able to boot windows once for ten times, every time after reboot NTFS' chkdsk finds problems with filesystem and the VM is unable to boot again. What am I missing? VM disk config: <disk type='file' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source file='/var/lib/libvirt/images/windows2012r2.img'/> <target dev='vda' bus='virtio'/> <boot order='1'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> Initiator side: root@initiator:~# btrfs version btrfs-progs v4.13.3 root@initiator:~# uname -a Linux initiator 4.15.0-0.bpo.2-amd64 #1 SMP Debian 4.15.11-1~bpo9+1 (2018-04-07) x86_64 GNU/Linux root@initiator:~# btrfs version btrfs-progs v4.13.3 root@initiator:~# cat /etc/debian_version 9.4 root@initiator:~# iscsid -v iscsid version 2.0-874 BTRFS mount options: _netdev,noatime,nodiratime,compress=lzo Target side: root@target:~# dpkg -l | grep iscsi ii iscsitarget 1.4.20.2-10.1 armel iSCSI Enterprise Target userland tools root@target:~# uname -a Linux target 2.6.31.8 Mon Nov 23 04:30:20 CET 2015 v0.0.9 Mon Nov 23 04:30:20 CET 2015 armv5tel GNU/Linux PS. There's nothing interesting in dmsg, besides (target side): iscsi_trgt: scsi_cmnd_start(1045) Unsupported 85 iscsi_trgt: cmnd_skip_pdu(459) 5e000000 1c 85 0 Which seems to be harmless and is probably generated by smartd. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
