Hi! Currently I plan a migration of a large VM (MS Exchange, 300 Mailboxes and 900GB DB) from qcow2 on ext4 (RAID1) to an all-flash Ceph luminous cluster (which already holds lot's of images). The server has access to both local and cluster-storage, I only need to live migrate the storage, not machine. I have never used live migration as it can cause more issues and the VMs that are already migrated, had planned downtime. Taking the VM offline and convert/import using qemu-img would take some hours but I would like to still serve clients, even if it is slower. The VM is I/O-heavy in terms of the old storage (LSI/Adaptec with BBU). There are two HDDs bound as RAID1 which are constantly under 30% - 60% load (this goes up to 100% during reboot, updates or login prime-time). What happens when either the local compute node or the ceph cluster fails (degraded)? Or network is unavailable? Are all writes performed to both locations? Is this fail-safe? Or does the VM crash in worst case, which can lead to dirty shutdown for MS-EX DBs? The node currently has 4GB free RAM and 29GB listed as cache / available. These numbers need caution because we have "tuned" enabled which causes de-deplication on RAM and this host runs about 10 Windows VMs. During reboots or updates, RAM can get full again. Maybe I am to cautious about live-storage-migration, maybe I am not. What are your experiences or advices? Thank you very much! Kind regards Kevin _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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