Re: [Networker] NetWorker + Windows SAN Tapes

Gaddy wrote:

Hi all,

this is a little bit OffTopic, but hurts us at least twice a month ...

We have some "Dedicated Storage Nodes", which share fibre attached
LTO drives in an 3-frame IBM3584.
Switches\Directors are McData, HBAs different types of Emulex cards.

All tape drives (WWPNs) are bound to SCSI addresses using elxcfg /HBAnywhere.


If, for some reason (defect), we power off a tape drive,
some of the Storage Nodes (esp. Windows2003)
readdresses the devices "on the fly", e.g. \\.\Tape3 will become \\.\Tape2
(SCSI adresses do not change, because they are bound as described above).

Unfortunately NetWorker is not very happy with this behavior!
( I think, many of you can imagine that, can't you? )

So my questions are:

a) Can I stop Windows2003 from changing the logical device addresses?

I don't think there is a way to stop Windows doing this. Even when youhave implemented persistent binding there is still no way to force thecorrect mapping of Windows device files to SCSI addresses. This is aserious design limitation in Windows. Compare this to Solaris wheredevice files are only mapped when you force them to be. I'm not sure howwell Linux handles this situation, it is something I have been meaningto find out.

b) If I cannot, can I rearange the addresses ONLINE without
  rebooting the server (which is typical a large SAP+Oracle in production)

Again I don't know of a way to do this. I would like to know if there is.

Of course this does not just apply to SAN connected tape devices, itwould be just as much of a problem in a pure SCSI environment. Sadlythis is one of the reasons I would always advise clients not to useWindows for large NW servers or storage nodes.


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