Re: sg_persist triggers block kernel event ???

[Christophe Varoqui <christophe.varoqui@xxxxxxxxxxx>]

Reproduced on a fairly recent kernel :

cvaroqui@clementine:~$ sudo sg_persist -k /dev/sda

  ATA       SAMSUNG MZMTD512  DXT4

  Peripheral device type: disk

PR in: command not supported

KERNEL[227056.238465] change   /devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sda (block)

ACTION="">

DEVNAME=/dev/sda

DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sda

DEVTYPE=disk

MAJOR=8

MINOR=0

SEQNUM=2603

SUBSYSTEM=block

cvaroqui@clementine:~$ cat /etc/lsb-release 

DISTRIB_ID=Ubuntu

DISTRIB_RELEASE=14.04

DISTRIB_CODENAME=trusty

DISTRIB_DESCRIPTION="Ubuntu Trusty Tahr (development branch)"

cvaroqui@clementine:~$ uname -a

Linux clementine 3.13.0-23-generic #45-Ubuntu SMP Fri Apr 4 06:58:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Regards,

Christophe Varoqui

www.opensvc.com

On Sat, May 3, 2014 at 10:12 PM, Christophe Varoqui <christophe.varoqui@xxxxxxxxxxx> wrote:

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="">

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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