I observe this on a debian 7.5 server with a udevadm monitor running in the background :
# sg_persist -n -k /dev/sdbh
PR generation=0x0, there are NO registered reservation keys
KERNEL[448809.342461] change /devices/pci0000:20/0000:20:02.2/0000:24:00.0/host0/rport-0:0-3/target0:0:1/0:0:1:12/block/sdbh (block)
Every sg_persist command, with any options, trigger events.
On this server with more than 200 scsi devices, each receiving one read-key and one read-reservation every 10 minutes, this triggers quite a eavy load caused by 2 udev triggers :
1/ multipath -v0 $devpath
2/ udisks-lvm-pv-export $pv_uuid
Question is, is it normal for a "--in" sg_persist command to trigger a change event on the scsi device ? If not, what we can do about it ?