Mike Christie wrote: > Eddy Quicksall wrote: >> Is there a case where the iscsi layer will generate a SCSI TMF? If so, >> what >> are the cases? >> > > Every scsi command has a timer set on it. The value of the timer is > normally 60 seconds. You can see the value for each device here: > /sys/block/sdX/device/timeout > That is RW, so you can echo to it to change the value or you can edit > the udev rule for it (see the README for defaults on that). > > If the command does not complete within the command timeout, the scsi > layer will fire its error handler. The scsi eh will first ask the iscsi > layer if it wants more time. > > In recent kernels (2.6.25 and above or if using the open-iscsi.org > modules with older kernels), the iscsi layer will only ask for more time > if we want to send a nop to check if the target is there and responding > (we will send a nop if we have not got any traffic for > node.conn[0].timeo.noop_out_interval seconds). We do this because the > scsi eh is very slow and has issues, and we only want to run it if we > really have to. > > If it turns out that the connection is good, we let the scsi eh do its > thing. It will first stop all new IO from being sent to the driver. Then > it will try to abort the outstanding tasks by calling the iscsi layer > abort callout which we send a abort task for. If the abort does not > complete within node.session.err_timeo.abort_timeout, we assume the > connection may be bad and just drop the session and try to relogin. If > the abort failed, then we will try a lun reset. If that fails or > timesout (node.session.err_timeo.lu_reset_timeout), we will drop the > session and try to relogin. There are patches floating around to try a > warm target reset after the lun reset, but they had issues with some > targets and is not merged. >
Oh yeah, if you run sg_reset -d /dev/sdX you can force the iscsi layer to send a lun reset on /dev/sdX --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-iscsi@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/open-iscsi -~----------~----~----~----~------~----~------~--~---
