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.