11/17/2007
Data Test Program (dt)
37
No Progress I/O Timing
nalarm=value and noprogt=value options useful to detect slow or no I/O times, esp. during failovers.
nalarm() generates SIGALRM signal which can only be delivered during interruptible kernel sleeps, thus it’s not always sent.
n
nExample:
ushaix11# ./dt of=/dev/rhdisk7 bs=64k aios=16 pattern=iot \
u      alarm=3s noprogt=15s runtime=5m stats=brief
u[ Initiated controller takeover to force path failover. ]
udt: No progress made for 18 seconds!
udt: No progress made for 21 seconds!
u ...
udt: No progress made for 39 seconds!
u