On Fri, May 22, 2015 at 12:30 AM, Peter Lieven <p...@kamp.de> wrote: > Hi, > > next libiscsi version will allow to define command timeouts. At least for > sync commands this > was in fact possible since somewhen in 2013. Per default this timeout is > disabled. >
Just to mention that this does not require any API changes or need to update library version requirements. It just require that the application will be calling iscsi_service(iscsi, 0) at regular intervals to trigger the timeout scans. On older versions of libiscsi, this will be a no-op, so situation is unchanged and timeouts may not work. On newer versions of libiscsi this will actually process the timeout scanning and cause the timeouts to actually happen. > > I would like to at least define a timeout for the sync commands (login, > readcapacity, inquiry, logout etc) > of about 5000msec. The chance to the iSCSI driver of qemu would be minimal > for that. The timeout > handling is done in the sync event loop of libiscsi. > > Is the idea that when a timeout occurs, the callback will eventually trigger an attempt to tear down and reconnect the session? I think a lot of/most linux kernels (guests) have a default timeout that they will perform a full bus reset once a task has hung for 60 seconds. Thus a tmeout or <<60 seconds will give you a lot of time to do several attempts to bounce the session to the target and try to recover before it hits the guest. My question is if it would be a good idea to have timeout (fairly high of > course) for all other commands as well? > > Peter > >
