Comment 54 for bug 1470250

This problem started more than a year ago, I decided together with my hoster to look at alternatives. Backup is the only thing that is causing problems for us with HyperV. The problem is two fold. First, the read-only state machines get into when generating the backup. Second, the read/write spike we see during a backup.

While this topic is focussed on the backups, the latter (spikes) is more and more causing problems. The more data getting on the disk, the higher the spikes are. Http requests that usually take < 100 ms are causing multiple seconds. More specifically, requests that involve write operations tend to have these characteristics. The read-only already made us reduce the amount of backups, because we want to decrease the risk of downtime. Now, with this (new) problem, it is almost impossible that a client does not suffer from a backup. That situation is wrong.

Since, it is so hard to debug (impossible for us to replicate behaviour on a test machine) and it is hard to tell when the problem will be solved, we decided, after a year, to look at alternatives. Nonetheless, thanks for the help we got here. That is much appreciated.