Poor IO Performance due to Failing RAID Controller Battery
All IO performance with AppAssure jobs is unexpectedly worse than normal. When Resource Monitor is opened on the Core server and the Disk tab is selected you see a very high Time percentage as well as a very high disk queue. Stopping the Core.Service still shows these characteristics when you run test IO work on the troubled volume. Opening your server manager software (such as Open Manage) to gauge the installed hardware specifications reveals that the RAID controller battery may be faulty.
A healthy RAID controller battery assists in the RAID's write performance with the write-back cache policy. In most controllers, when the battery is near or at failure the controller will default to write-through and the IO performance is significantly noticed with all IO jobs.
Replace the RAID controller battery by contacting the hardware vendor. While this maintenance is going on it is recommended to verify that drivers and firmware for the RAID controller are also up to date. Once the system shows a good health report then all IO performance should be back to normal.