Stefan, You summed it up pretty well... -- james s > -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx > [mailto:linux-scsi-owner@xxxxxxxxxxxxxxx] On Behalf Of Stefan Richter > Sent: Thursday, July 31, 2008 4:35 AM > To: Gal Rosen > Cc: linux-scsi@xxxxxxxxxxxxxxx > Subject: Re: SCSI device rescan, detection of disconnected > device, or switched devices. > > Gal Rosen wrote: > > I will try to make my question more clear. > > I would like to put a box between the client and the > storage, and to be > > fully transparent against the host. All changes on the storage > > (add/remove/extend devices) should be present automatically to the > > client. In a direct connection between client and storage the > > administrator will coordinate between the client and storage before > > making any changes, in my configuration I do not want to add > > administration work on my box that stands between the client and the > > storage. > > Addition is simple, the application on my box can once in a > while scan > > the SCSI BUS, and then the Linux system will create new sg devices. > > In removal of a device the Linux system will not remove sg > devices after > > scan. In that case again I can do it from my application, > such when I > > get attention on SCSI command, I can decide to remove the device by > > echoing to the /sys file system. > > I really don't know how the FibreChannel drivers handle > device removal. > But from what I gather from the documentation of > fc_remote_port_delete(), which the qla2xxx drivers use, the /dev/sg > devices should automatically disappear > - after a connection loss timeout, > - provided that userspace doesn't have the device file opened > (among else this is manifest in the kernel in a reference count of > the logical unit device representation), > - provided that you manage your device files with udev. > > http://lxr.linux.no/linux+v2.6.26/drivers/scsi/scsi_transport_ > fc.c#L2756 > > That would be basically just like SCSI device files are created and > destroyed on the fly for USB or FireWire devices for example. Except > that FC has the additional configurable connection loss timeout which > hides temporary connection losses from applications. > > (However, better wait for an answer of somebody who actually > uses FC or > knows the drivers. I only have experience with FireWire.) > -- > Stefan Richter > -=====-==--- -=== ===== > http://arcgraph.de/sr/ > -- > To unsubscribe from this list: send the line "unsubscribe > linux-scsi" 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 linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
