SQL backup hangs and fails with Backup Window Expired
Problem description
SQL backups hang and then fail with the Backup Window Expired error. The backups may appear hung, run intermittently, stop, and finally fail.
Cause
You run into this issue when Microsoft SQL is installed on a Windows server, and all or maximum server memory is allocated to the SQL application.
Traceback
[2021-07-07 15:05:11,615] [INFO] <InstrThread(Thread-5)> INSTRUMENTATION ESTIMATION STAT END:
[2021-07-07 15:07:04,443] [INFO] <PingThread(Thread-4)> Pinging Sync Server
[2021-07-07 15:07:04,561] [WARNING] <PingThread(Thread-4)> No connection available in pool to execute_rpc_all_active.
[2021-07-07 15:07:04,561] [INFO] <PingThread(Thread-4)> Pinging Server
[2021-07-07 15:09:04,562] [INFO] <PingThread(Thread-4)> Pinging Sync Server
[2021-07-07 15:09:04,585] [WARNING] <PingThread(Thread-4)> No connection available in pool to execute_rpc_all_active.
[2021-07-07 15:09:04,585] [INFO] <PingThread(Thread-4)> Pinging Server
[2021-07-07 15:11:04,586] [INFO] <PingThread(Thread-4)> Pinging Sync Server
[2021-07-07 15:11:04,596] [WARNING] <PingThread(Thread-4)> No connection available in pool to execute_rpc_all_active.
[2021-07-07 15:05:11,157] [INFO] <InstrThread(Thread-5)> INSTRUMENTATION ESTIMATION STAT START:
Note : Logs shows we backed up some data and then waited for the response from the server and started the thread again.
Resolution
Allocate 10-20% of the physical memory for the server's operation. Refer to Microsoft documentation on configuring a fixed amount of memory.