On Thu, 30 Oct 2008 07:55:12 +0100 Tomasz Chmielewski <mangoo@xxxxxxxx> wrote: > FUJITA Tomonori schrieb: > > On Wed, 29 Oct 2008 12:26:58 +0100 > > Tomasz Chmielewski <mangoo@xxxxxxxx> wrote: > > > >> Sometimes, I need to resize the device on the target. > >> > >> Technically, I do this as follows: > >> > >> lvextend -L+5G /dev/san14/blah1 > >> tgt-admin --update tid=20 -v -f > > > > What does exactly 'tgt-admin --update tid=20 -v -f' do? Please explain > > what tgtadm operations are performed. Please do so at all times (hint: > > I don't understand how tgt-admin works). > > Basically, it disconnects all initiators, removes the target, and adds > it again. Removing the lun and adding it again would be enough, as you > also write below. OK, I thought that you wants to resize a device without disconnecting initiators or removing the target. > > Well, unless you delete a logical unit and add it again, tgtd doesn't > > know the new size. So probably, we need to a new interface to notify > > tgtd of the change. > > > > > >> However, the initiators won't see the change unless we "rescan" the > >> device, i.e.: > >> > >> echo 1 > /sys/block/sdah/device/rescan > > > > Unless you use 2.6.28-rc kernel, it doesn't work, I think. > > It works for me with 2.6.18 kernels. Sorry, I should have been more specific. Yes, the above operation issues commands like READ CAPACITY so it works from the perspective of SCSI but well you might want something more with resizing: http://marc.info/?l=linux-scsi&m=122005161211449&w=2 > >> This is a boring thing to do when we have more initiators connected to > >> that target. > >> Also, the initiators will likely have a different device used for that > >> target (/sys/block/<DEVICE>/device/rescan), making the thing even more > >> boring. > >> > >> > >> Is it possible to send a reset/rescan to all initiators connected to a > >> given target, which would trigger the initiator to rescan the device > >> (and its size)? > > > > A scsi device can notify initiators of such event via UA (unit > > attention), google "CAPACITY DATA HAS CHANGED". tgt has the mechanism > > to handle UA so it's easy to support it. However, on the initiator > > side, Linux doesn't detect such event automatically. > > I see. > So let's just hope Linux will detect such events one day ;) > > > -- > Tomasz Chmielewski > http://wpkg.org > -- > To unsubscribe from this list: send the line "unsubscribe stgt" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
