Dear all, I am doing more experiments with Ceph iSCSI gateway and I am a bit confused on how to properly repurpose an RBD image from iSCSI target into QEMU virtual disk and back
First, I create an RBD image and set it up as iSCSI backstore in gwcli, specifying its size exactly to avoid unwanted resizes Next, I connect Windows 2008 R2 to this image (enable MPIO before connect and select MPIO policy 'Failover only' for the accessed device) Then in Windows Disk Management I initialize the physical disk with GPT, convert it into Dynamic disk and create a simple NTFS volume in its free space Then in the same console I put the disk 'offline', and in iSCSI control panel I disconnect the session from Windows side Then I attach the same RBD image to QEMU/KVM virtual machine with Ubuntu 18.04 as virtio/librbd storage drive Then I boot Ubuntu 18.04 VM, find NTFS filesystem using 'ldmtool create all', and during ntfsclone from external disk I discover that RBD image is mapped read-only Ok, I stop Ubuntu VM, do 'rbd lock rm' for this image (lock is held by tcmu-runner, I suppose), restart Ubuntu, restart ntfsclone, and this time it is going well. Btw, ntfsclone onto device-mapper target created by ldmtool is going about 2x faster than directly onto Virtio Disk (vdN), so it transferred my 1600+GB in just 13+ hours instead of 27+ Ok, external NTFS is cloned seemingly well, I shutdown Ubuntu VM (it properly removed the RBD lock on shutdown) and try to access it from Windows by iSCSI again. And at this moment I stumble into trouble. First, I don't see added RBD image in 'Devices' on iSCSI initiator control panel. This I tried to resolve by restarting tcmu-runner. After reconnect from Windows side, RBD image became visible in devices (and RBD lock from tcmu side was reacquired), but its MPIO button was disabled, so I could not check or change MPIO policy (surely I enable MPIO in 'Connect' dialog). I tried also to restart rbd-target-gw but this also did not help. Restarting Windows server also did not improve the situation (MPIO button still disabled). What should I try to restart next, to avoid restarting the whole Ceph host ? May be unload/reload some kernel modules ? Thanks in advance for your help. Hope I could determine and resolve the problem myself, but this could take more time than getting help from you. _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
