On 05/24/2010 11:06 AM, Taylor wrote:
Adjusting node.conn[0].timeo.noop_out_interval and
node.conn[0].timeo.noop_out_timeout to 0
didn't seem to make a difference.  But increasing the value of /sys/

If it did not make a difference then it might not have got set right. If you set them to 0, then you should not see the ping timeout messages anymore (you might still see the target request logout ones, and that is what we are trying to see with this test). Did you just set it in iscsid.conf or did you set it in the node db by running

iscsiadm -m node -T ... -o update -n node.conn[0].timeo.noop_out_interval -v 0

then repeat for the other value (you can also set it in the node db by setting it in iscsid.conf then rerunning the iscsiadm discovery command).


block/sd#/device/timeout from 30 to a higher number, like 360, seems
to have improved things...

Is that something you would expect?  Do you know of a sensible value


No. It might improve thoughput of some IO test, but it would not remove the those log messages you sent before.


for setting the timeout under /sys/block/sd#/device, and what is
impact of increasing this?


It depends on the storage you are using.


8.1.2.1 Running Commands, the SCSI Error Handler, and replacement_timeout
-------------------------------------------------------------------------
Remember, from the Nop-out discussion that if a network problem is detected,
the running commands are failed immediately. There is one exception to this
and that is when the SCSI layer's error handler is running. To check if
the SCSI error handler is running iscsiadm can be run as:

iscsiadm -m session -P 3

You will then see:

Host Number: X State: Recovery

When the SCSI EH is running, commands will not be failed until
node.session.timeo.replacement_timeout seconds.

To modify the timer that starts the SCSI EH, you can either write
directly to the device's sysfs file:

echo X > /sys/block/sdX/device/timeout

where X is in seconds or on most distros you can modify the udev rule.

To modify the udev rule open /etc/udev/rules.d/50-udev.rules, and find the
following lines:

ACTION=="add", SUBSYSTEM=="scsi" , SYSFS{type}=="0|7|14", \
        RUN+="/bin/sh -c 'echo 60 > /sys$$DEVPATH/timeout'"

And change the echo 60 part of the line to the value that you want.

The default timeout for normal File System commands is 30 seconds when udev
is not being used. If udev is used the default is the above value which
is normally 60 seconds.

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