A 1 year old SBS 2011 server with Xeon processor and 32GB RAM, has started running very slowly again. This last time this occurred was two months ago and after several reboots, with a change of AV, swap file location and C: drive space increase, it started working normally again.
After a further reboot due to more Windows updates ( which were successful and different from two months ago ), it has reverted back to running very slow again, which seems to also cause the SBS backup to time out with a 'Creation of the shared protection point timed out. Unknown error (0x81000101)'.
There is no obvious cause in the event viewer logs and there is currently 42GB free out of 120GB on the C: partition, whereas previously the space was around 10GB when the problem started, although disk space may be unrelated.
However about half of the VSS writers seem to be in a 'Retryable error' state ( when entering vssadmin list writers from a command prompt ), which will require a further reboot to at least temporarily resolve. It may be that the failed backup procedure then causes the writers to fail again.
In the processes area of Task Manager, CPU usage is between 90-100% most of the time and physical memory is around 84% usage. The top processes using memory are the Microsoft Exchange DB Store ( 11.5GB ), SQLserv ( 2 totalling 3.6GB ) and IIS Worker Processes ( 4 totalling 1.8GB ).
It is my understanding that Exchange and SQL can utilise any resources that are free and then release them when another process requires them, which may account for the high usage, but it is unclear what is causing the VSS writer errors. Also there are only 5 users, with no additional 'resource demanding' programs installed.
What steps can be taken to troubleshoot this further, with a view to improving the performance again, to stabilise the VSS writers and to stop the backup from timing out?