6/30/2010
Data Test Program (dt)
52
No Progress I/O Timing
nalarm=value and noprogt=value options useful to detect slow or no I/O times, esp. during failovers.
nalarm() API previously used, now replaced with monitoring thread to avoid issues with I/O blocking signal delivery.
nExample no-progress trigger script.
nAlso see I/O Monitoring Tool (iomon) Wiki.
n
nExample:
ushaix11# ./dt of=/dev/rhdisk7 bs=64k aios=16 pattern=iot \
u      alarm=3s noprogt=15s runtime=5m stats=brief
u[ Initiate controller takeover to force path failover. ]
udt: No progress made during write on /dev/rhdisk7 for 18 seconds!
udt: No progress made during write on /dev/rhdisk7 for 21 seconds!
u ...
udt: No progress made during write on /dev/rhdisk7 for 39 seconds!
u