I’ve noticed several people who were familiar with using trace events with cellsrv, were uncertain about how to use tracing the new offload server architecture. So whereas in the past you could have added tracing to SmartScan processing with:
> cellcli -e 'alter cell events = "trace[fplib.sage_data] disk=lowest, memory=lowest"'
the new syntax to turn it on is:
> cellcli -e 'alter cell offloadgroupEvents = "trace[fplib.sage_data] disk=lowest, memory=lowest"'
and to turn it off:
> cellcli -e 'alter cell offloadgroupEvents = "trace[fplib.sage_data] off"'
Do not use anything higher than “disk=medium, memory=medium” since the higher levels of tracing will cause the heartbeat monitor to fail with timeout issues.
The SmartScan trace events available under the fplib (Filter Processing Library) facility are:
fplib.fplib_main, fplib.sage_cache, fplib.sage_txn, fplib.sage_data, fplib.sage_index
In the cell trace directory hierarchy each offload server will have its own trace directories
diag/asm/cell/SYS_122010_150220/trace
diag/asm/cell/SYS_112331_141117/trace
In a future post I will cover how to use named offload groups to isolate the traces for a single session.
Roger MacNicol,
Data Storage Technology Group