(Oops, I clicked the wrong reply button) Hi Fujita, On Thu, 19 Jan 2012 06:31:19 +0900, FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > **UNKNOWN CHARSET** <me@xxxxxxxx> wrote: > >> When a LUN is created with tgtd, tgtd immediately open()s the backing >> store, however I don't think data is actually read before a connection >> from an initiator is made. >> >> My question is, is there an option to make tgtd open the file the >> moment a connection is made (and not before)? >> And if this is not currently possible, what would it take to implement >> this? >> As a related feature, the backing store could be close()d after the >> (last) connection has ended. > > tgt enables you to add/remove logical units any time. Why you can't > add a device such as lvm volumes when it's ready? Adding works fine. The problem is, the moment it is added, the file/volume/disk is 'in use' (by stgt), this prevents (for example) the lvm tools from changing or removing the device. For example, I want the ability to export all volumes in a LVM volumegroup automatically, this can easily be done with a udev script to add the LUN. The same could be done for removing the volume, only stgt prevents this by making LVM mark the device 'in use'. I would like a option so stgt only 'uses' the device, if there is a connection that _really_ uses the device. Is short this means stgt should defer the open() call on the backing store until a connection is requested. Likewise, it should close() the backing store when the last connection closes. I am guessing such a feature does not yet exist (I couldn't find it), and am interested to know your guess on how hard this would be to implement. If there are any technical arguments against such a feature, or it requires a lot of changes to stgt, I should investigate alternative ways to manage the volumes (by using administration tools that allow hooks to remove the volume from stgt before trying to change it). Greetings, Môshe van der Sterre -- 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
