For example, by running cat /var/log/SMlog | grep -i exception or cat /var/log/SMlog | grep -i error on the XenServer host with the affected storage.Ĭoalesce jobs can also fail to run if the SR does not have enough free space. However if you repeatedly get this message and it seems XenServer is not coalescing, You can take a few steps to determine why.įirst check SMlog on the XenServer host for messages relating to VDI corruption or coalesce job failure. # Troubleshooting a constant VDI Chain Protection message (XenServer failure to coalesce)Īs previously mentioned, this message can be normal and it just means XenServer needs to perform a coalesce to merge old snapshots. You can read more on this on our dedicated blog post regarding XenServer coalesce detection (opens new window). Just remember this: a coalesce should happen every time a snapshot is removed. The backup job will fail, but XenServer itself should eventually automatically coalesce the snapshot chain, and the the next time the backup job should complete. In the end, this message is a protection mechanism preventing damage to your SR.

The first issue is a chain that contains more than 30 elements (fixed XenServer limit), and the other one means it's full because the 'coalesce' process couldn't keep up the pace and the storage filled up.

SR_BACKEND_FAILURE_44 (insufficient space).

Without this detection, you could have 2 potential issues: Xen Orchestra is the only XenServer/XCP backup product that takes this into account and offers protection. If we don't, this will lead to catastrophic consequences. But we can check your existing VDI chain and avoid creating more snapshots than your storage can merge. This mechanism and scheduling is handled by XenServer itself, not Xen Orchestra. This means generally we cannot take too many new snapshots on said VM until Xenserver has finished running a coalesce job on the VDI chain. When a snapshot is deleted, either manually or via a backup job, it triggers the need for Xenserver to coalesce the VDI chain - to merge the remaining VDIs and base copies in the chain. # VDI chain protectionīackup jobs regularly delete snapshots.

While a backup job is running, you should see activity in the 'Tasks' view (Menu/Tasks), like this:Īnother good way to check if there is activity is the XOA VM stats view (on the Network graph). This section is dedicated to help you if you have problems with XO Backups.

Error: Expected values to be strictly equal.

How to decrease disk size xenserver