| Title: | Ask the Storage Architecture Group |
| Notice: | Check out our web page at http://www-starch.shr.dec.com |
| Moderator: | SSAG::TERZA N |
| Created: | Wed Oct 15 1986 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 6756 |
| Total number of notes: | 25276 |
Hello,
We are about to sell 3 Tape Library Units to one of our most
important
customers.
The products in question are (3) TL896 Tape Libraries to be connected
to a VMS (CI)Cluster formed by two AlphaServer 8400 and an AlphaServer
4100.
The idea is to connect every tape transport unit to a different SCSI
controller. Hence, we would be using six (6) SCSI busses per tape
library
1) Is it possible to directly get to the SCSI of each transport of the
library to get higher performance ? From reading the
Customer/Sales
Updates, this is not clear...
-
2) If this is possible, would the software(below detailed) be able to
handle
the library from multiple SCSI controllers ? From different members
of the
cluster ?
3) Are there any restrictions in this type of configurations about
where the
robot device (SCSI port?) should be attached ? (We are thinking of
connecting them to the HSJ controller attached to the CI)
4) If this kind of (multiple controllers for a single library)
configuration
is supported, which is the controller card to be used ? The KZPSA is
shown as supported in the Sales Update for TL89x devices. But SLS
won't
work with it (as described in SPD 29.67.16)
We're proposing SLS (V2.8A) to drive the tape libraries, and we're not
quite
---
We're proposing SLS (V2.8A) to drive the tape libraries, and we're not
quite
sure of how license policy applies to the cluster environment. Should
we
sell one license for the cluster system (3 AlphaServers) or a license
for
each Cluster member ?
Our customer is also considering HSM (for OpenVMS) and the same
question
applies here...
Thank you
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 6754.1 | SSDEVO::ROLLOW | Dr. File System's Home for Wayward Inodes. | Thu Jun 05 1997 11:19 | 46 | |
re: #1 The question doesn't make sense. If you're using one SCSI controller for each tape, then each is directly connect to that SCSI adapter. Of course, you haven't said what SCSI controller you're using. If you are using an HSJ to connect the tapes then no, it isn't connect directly to the host, since it is connected through an intermediate controller. Further the HSJ is a loss in this case since the drives are Fast/Wide SCSI and the HSJ backend busses aren't. You want to use KZPSAs on the host. The problem, is that each host is probably limited to seeing the drives connected to it. This may not be an issue, but it is worth noting so you know it might be one. I don't know if OpenVMS supports serving of SCSI tapes across the cluster. Putting the tapes on a shared bus has its own problems. re: 2 SLS/MDMS recently tested a configuration where the tapes in a library were connected to different hosts. I think they now support such a configuration. !! BUT !!! The library media changer has to be on a common bus, accessible to each host running the software. The only way to get the the media changer on that common bus is to put IT on an HSJ. Since the TL896 only has 6 bus connections, and you want one drive per bus, one drive will have to be on the HSJ with the attendant performance loss. I think this answer #3. re: 4 You need to ask the SLS product manager why the KZPSA isn't supported. They have done some testing with them, so I don't understand where the restriction would come from. I also haven't read the SPD to see exactly what the problem is. re: Versions Verify that the version you plan to use supports the TZ89. | |||||