[dm-devel] sg_persist triggers block kernel event ???

[Christophe Varoqui]

Hi list,

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)
ACTION=change
DEVNAME=/dev/sdbh
DEVPATH=/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
DEVTYPE=disk
MAJOR=67
MINOR=176
SEQNUM=261605
SUBSYSTEM=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 ?

Best regards,
Christophe Varoqui
www.opensvc.com
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