Networker

Re: [Networker] DDS woes

2003-01-21 06:23:53
Subject: Re: [Networker] DDS woes
From: "Wood, R A (Bob)" <WoodR AT CHEVRONTEXACO DOT COM>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Tue, 21 Jan 2003 11:23:37 -0000
Andre,
        I have seen something similar in our environment (we are using
AlphaStor 2.1.2 to do the device sharing, Solaris 8, NW 6.1.2, W2K
Cluster SAN Storage nodes, STK L180 library 4 x LTO 2 x DLT via
fibre/SCSI bridge, Brocade Silkworm 2800 switches)

        Bear with me while I describe what we had and what we were doing
when we noticed this behaviour. We had AlphaStor 1.7 (or something like
that) with the above environment. Everything worked just fine. The
Solaris machine would be the first to 'grab' the devices, it would grab
the device as 'shared', NT or W2K would then attach to the devices. As
the devices were already allocated, Windows attached as share devices.

        Now, we upgraded to AlphaStor 2.0. What happened now was, the
Windows servers were the first to grab the devices, being the first to
grab the drive the server would attach as non-shared device. Once it had
attached this way, it wouldn't let other servers share the device, it
gave a message similar to the one you describe.

        We upgraded to AlphaStor 2.1 then 2.1.2 but we still can't force
the Solaris box to be the first to grab the devices.

        It seems that Windows defaults to attaching as non-shared unless
forced to use shared because another device has attached to it. 

        We don't have a fix for it yet.

Regards
Bob
        

-----Original Message-----
From: Andre Beck [mailto:networker AT IBH DOT DE] 
Sent: 21 January 2003 10:31
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] DDS woes


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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