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Conference decwet::winnt-clusters

Title:	WinNT-Clusters
Notice:	Info directories moved to DECWET::SHARE1$:[NT_CLSTR]
Moderator:	DECWET::CAPPELLOF

Created:	Thu Oct 19 1995
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	863
Total number of notes:	3478

604.0. "How many shared SCSI buses?" by BIGCHZ::EZZELL (Mike Ezzell) Thu Feb 06 1997 17:16

How many shared SCSI buses are allowed in a NT cluster?

I have been told that only one shared SCSI bus is supported in V1.0, but the
Cluster White Paper implies multiple.  The Sales Guide shows our support for
multiple SCSI buses as an advantage over our competitors that only support
one.  The Supported Hardware List (SUPPORT.DOC) doesn't mention the number of
buses supported.

I was looking for the SPD, but I was told that there was not one for this 
product.  That's too bad, because that's the best place to put this kind of 
information that changes from release to release.

T.R	Title	User	Personal Name	Date	Lines
604.1	Only Limit is PCI Slots	ACISS2::SDATZMAN		`Fri Feb 07 1997 07:58`	6
	Mike. My understanding is that the only practical limit is the number of available PCI slots (i.e., for KZPSA's or Adaptec 2944's) on the servers being used. Steve
604.2		MPOS01::naiad.mpo.dec.com::mpos01::cerling	I'[email protected]	`Fri Feb 07 1997 10:04`	16
	It has been stated several times in this conference that you are only limited to the number of slots you have available. >>Cluster White Paper implies multiple. The Sales Guide shows our support for >>multiple SCSI buses as an advantage over our competitors that only support >>one. The Supported Hardware List (SUPPORT.DOC) doesn't mention the number of I also saw that remark about single SCSI support for our competitors. However, I just read Compaq's technical write-up on their Online Recovery Server. Their documentation shows that they can support multiple SCSI as well. Methinks our marketing folks better research what they are saying. Is Compaq's documentation misleading or can they, in fact, support multiple SCSI adapters to shared storage? tgc
604.3	As many busses as you want	DECWET::CAPPELLOF	My other brain is a polymer	`Fri Feb 07 1997 13:12`	9
	It is true. Digital Clusters for Windows NT will support as many shared SCSI busses as you can fit in your machine. If you have a SCSI bus with several disks on it, Digital Clusters can provide an advantage over Compaq Online Server. With Digital Clusters, you can distribute the disks any way you want. Server A can own some of the disks, while Server B owns the others. In event of a failover, all disks move to the live server. In contrast, Compaq's current solution requires all the disks on a bus to be owned by one system or the other.
604.4		MPOS01::naiad.mpo.dec.com::mpos01::cerling	I'[email protected]	`Fri Feb 07 1997 17:51`	14
	I definitely agree with the benefit of the way we handle our disks on the SCSI versus how Compaq does it. Ours is FAR superior. My point, however, was that presentations that I have heard marketing people give state that Compaq can only have a single shared SCSI. Reading their technical description leads me to believe that they can say the same thing about the number of shared SCSI as we can. They cannot talk about the granularity of sharing that we can, because they do have to fail over the entire bus. Also, it doesn't fail for a SCSI adapter failure. The only time it fails is if the processor fails or the processor hangs or gets so busy it can't issue a keep alive msg. Again, not even close to what we do. tgc
604.5	KZPSA limited to primary PCI in 1000/1000A	CIVPR1::SIMMONS	Mike Simmons (301) 918-5597	`Fri Mar 14 1997 22:23`	5
	The PCI slot limit currently a serious consideration. Currently, the KZPSA is only supported on the 3 primary PCI slots in the AS1000A 5/400. But the Number Nine Vision Graphics 330 is only supported in one of these primary slots. In addition, the De500 has performance degradation in secondary PCI slots.