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.
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