Networker

[Networker] DDS woes

2003-01-21 05:36:15
Subject: [Networker] DDS woes
From: Andre Beck <networker AT IBH DOT DE>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Tue, 21 Jan 2003 11:31:24 +0100
Hi,

I'm lab-testing dynamic drive sharing with 6.2 in a SAN environment
consisting of Compaq (aka HP) DL380s with Compaq (aka Emulex) FC HBAs,
a Compaq (aka Brocade) FC switch, a MSA1000 RAID array (not of the most
relevance here) and an Overland Neo loaderXpress with FCO card. There
are some issues with DDS that disturb me:

1) Whenever the shared tape is switched between the two servers (one
   beeing the Networker server, the other beeing a storage node) Win2k
   issues nonsense messages of illegal device removal (dunno exactly
   how this would be called in an original W2k, got a localized german
   version here) - it warns me that I would have illegally removed the
   SDLT320 Tape Drive (note, not the medium, but the *drive*). It even
   does this in the midst of a running backup. It's the same message
   you get when you remove a PC-Card without shutting it down first.
   According to the Legato docs I have installed the library drivers
   on both W2ks and disabled the library, leaving all other levels of
   removable media handling enabled. I've also tried with the entire
   removable media service disabled, but the messages were still popping
   up on both servers.
   I've got the feeling that this whole issue is due to the FC HBAs
   beeing plugged into hotplug PCI slots and thus beeing under removable
   device control which is extended to all subdevices connected via them,
   but I'm not sure whether this should make any difference.
   The FC-2-SCSI Router on the FCO card is configured to hide its own
   LUN.

2) DDS licensing clearly states that you need one DDS license per drive to
   be shared. For entirely unknown reasons, I need two. As soon as I remove
   either of the two DDS licenses, I get a log message of one of the two
   shared devices beeing disabled due to insufficient licensing. We've
   opened a case with Legato and our distributor for this, but I'd still
   like to aks whether anyone else has already seen this. Note, it's
   one physical drive, but two shared (virtual) devices. The need for
   two DDS licenses contradicts the docs which emphasize intensely on
   the DDS license to be required per *physical* drive.

3) Regarding the somewhat stress sensitive tape pickup mechanism of DLT,
   I really don't like the fact that DDS requires unloading and instantly
   reloading the same cartridge to move it between the virtual drives. I
   don't expect a way around this, as it seems to be designed that way,
   but I'll ask anyway.

>From the points above, what clearly disturbs me most is 1), as it seems
that these errors even cause media to be errouneously marked as full.
Anyone with some insight on this?

TIA,
Andre.
--
Thanks to DRM technology, this mail will destroy itself in five seconds.

-> Andre Beck    +++ ABP-RIPE +++    IBH Prof. Dr. Horn GmbH, Dresden <-

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