I have some new information. I happened to be logged on to the virtual Linux server's virtual console in VM while attempting to vary the device offline in a separate remote ssh session. When I did so, I saw messages on the virtual console like I see during boot-up when the device first comes online. That tells me that chccwdev (or echo redirection to the appropriate file in the /sys virtual file system) does get the device offline, but the device is then immediately brought online again by the dasd driver. Further testing seems to indicate that a device which *IS NOT* specified in the dasd option of the dasd_mod kernel module can be brought online and offline manually just fine. But a device which *IS* specified in the dasd option of the dasd_mod kernel module is immediately brought online again by the dasd_mod kernel module once it is varied offline. This now appears to me to be a bug in the dasd_mod kernel module, which is part of the Linux kernel itself. The dasd_mod kernel module behaved as expected in the 2.6.18 kernel of etch (and earlier), but somewhere between the 2.6.18 and 2.6.24 kernels, the aberrant behavior began.
In my case, I have a file called /etc/modprobe.d/dasd which contains the following line: options dasd_mod dasd=0.0.0200-0.0.0203 Any dasd device in the device number range 200-203 cannot be varied offline, except for a few milliseconds. Then the dasd driver varies it back online again. This is incorrect behavior. The driver should vary the device online automatically at boot time, and assign device nodes to the devices in the order that they are specified (200 = /dev/dasda, 201 = /dev/dasdb, etc.). But if the device is varied offline manually, it should be left offline until it is varied online manually again. This ticket should be reassigned to the kernel. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
