On Wed, 6 Feb 2008 09:12:42 -0500, David Boyes <[EMAIL PROTECTED]> wrote:
> > > zfcp does not create any udev/hotplug events. Related events are: > > - The CCW device is attached to the system > > - The CCW device is removed from the system. > > - A SCSI host adapter is registered from zfcp. > > - The SCSI host adapter is removed from zfcp. > > > > Setting the CCW device online or offline does not generate > > udev/hotplug events. > > That seems kind of counter-intuitive. A device clearly just changed > state in an important way -- shouldn't that be something udev should > care about, or at least be notified of? Udev can always choose to ignore > the events. Well, uevents are mainly created when devices are added/removed to/from the system. Setting a device online/offline only changes some attributes for an existing device. If ccw device drivers create/remove some block or character devices when the ccw device is set online/offline, userspace will be notified anyway (and usually userspace will be interested in the block/character device, not in the ccw device). If userspace needs more information than that, a device driver can generate uevents itself (like the dasd driver does for stage changes, which are interesting to some tools). > > > You might observe the fact that in old SLES9 kernels, the SCSI host > > adapter for zfcp was registered when setting the CCW device online and > > unregistered when setting the CCW device offline. This was changed, so > > that setting the CCW device offline, does not remove the SCSI host > > adapter. The change was necessary, because going through the sequence > > "offline adapter" -> "online adapter" has to present the same SCSI > > devices to not confuse the multipathing layer. > > Makes sense. OK, so no notification is generated in this case... > > > As an alternative, i would suggest putting the FCP adapters, ports and > > LUNs in some simple scripts, that do not rely on hotplug events. > > Ugh. Isn't that the point of hotplug support -- so that we don't have to > do stuff like that? ...so a better solution may be to have zfcp generate a uevent here? (I'm not too happy with adding uevents whether they are needed or not. Too many uevents create a high system load from some tools.) ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
