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L20/700 :(

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wayne_20
Advisor

L20/700 :(

hey! first to meet you all.
i got a problem for L20/700.can any one tell me how to attach the interface manager with the L20/700? we used a MPW card to transfer HVD to LVD.and which one i will connect with library-to-client SCSI control cables?
you know there lots of parts.i really got a mess.:(
:)
6 REPLIES
Ted Ellis_2
Honored Contributor

Re: L20/700 :(

you may need to give some more details on what you are trying to do.. but:

If your question is how to connect the library robot SCSI cable... it is typically chained off of the first tape drive. That is how our present library works and our old STK as well... now I am not sure about HVD or LVD for the robot vs drives

Is that what you are after? We had the older STK with 8 tape drives in it... the drives had their SCSI cables coming off of a fibre MUX which had its fibre connection to the server. Each MUX could handle 3 drives, so their were 3 MUx's

Ted

Brian M Rawlings
Honored Contributor
Solution

Re: L20/700 :(

You need more information. You need to know what kind of SCSI this library is set up for, HVD or LVD. You have a converter, but without knowing which direction you are converting, it is hard to make suggestions.

What kind of server is driving this library, and what kind of SCSI (HVD, LVD) is it using?

What kind of drives?

Basically, the library connection is pretty straightforward, but the devil's in the details. Here are some guidelines:

1> With HVD SCSI (20MB/s max, 15MB/s sustained), you can really only run DLT8000s, one per SCSI bus. The faster Ultrium drives (11MB/s or 15MB/s) can run into trouble if you get any compression at all in your backups.

2> The library itself (the SCSI connection to the robotics) takes almost no bandwidth, and should be daisy-chained with one of the drives, normally the first one.

3> Ultrium and 9840 drives need UltraSCSi (LVD) to sustain the kind of throughput they require, although they can run (poorly) on HVD SCSI, if that is the setup. Ultra is tricky, it can mean 40MB/s or 80MB/s, based on the slowest unit in the connection (host adapter or drive, either can throttle the other back to 40).

4> You can generally get away with daisy-chaining two UltraSCSI LVD drives on one SCSI bus, but if you get good compression (2:1 or better), only put one high-speed 15MB/s Ultrium drive or 8940 drive on a bus for best performance. 40MB/s derates to a sustained rate of 30MB/s or so, and compression increases the data transfer rate requirement at the same rate as the extra space you get from it...

5> If you have Ultra/LVD on the Library, but HVD on the Server (old K- or D-class?), and you have a LVD/HVD converter, you will only get the throughput of old "FWD" (now HVD) SCSI, which is about 14-16MB/s sustained (depending on I/O card; even less for HP-PB). This bottleneck may not be correctable, other than to acquire a small backup server like an RP2470, and change the connections to all Ultra/LVD.

6> If you need cables, HP has long ones and short ones. They will all work, but total bus length should not exceed 12m for LVD, and 25m for HVD. This generally is not a problem, if you use short cables for daisy-chain, and one long one for the server to library run. Some newer cables are "multi-mode", and can be used for HVD or LVD connections. Many older cables were one or the other (90 ohm vs. ?? 110 ohm ??), causing annoying problems if you used the wrong one. You should probably get new cables, if you need some, rather than sorting through your collection of unused ones (unless you really know which is which).

If you get back to us with more info, maybe we can be of more help. I'm afraid all I can do is generalize at this point.

Regards, --bmr
We must indeed all hang together, or, most assuredly, we shall all hang separately. (Benjamin Franklin)
wayne_20
Advisor

Re: L20/700 :(

well,you know the MPW is a card transfering HVD to LVD.the library used HVD SCSI original,doesn't it? we used HP Ultrium Drives for LVD interface.the menu tell us "when installing an Ultrium drive in the library, you must mach the cable types and terminators with the bus type" and "Native operation for both IBM and HP Ultrium tape drives is the LVD interface.To operate either drive as HVD,convert cards must be installed on the drive trays".
we plug the MPW card in MPC card.
well, that's it.ok?
:)
wayne_20
Advisor

Re: L20/700 :(

We have two drive towers , altogather 20 drives.
We connect 20 drives to the ports of Fibre Channel cards. Each card connects a FC port to two Ultra-2 SCSI ports.altogether 10 cards were installed in the slot of interface manager. The interface manager also contains a Remote Management Card (RMC) in slot 1, and a
controller card in slot 2.I wonder is there a connection between the interface manager with library? Or how can I used the the controller card in slot 2?
:)
wayne_20
Advisor

Re: L20/700 :(

hey!Brain. It is no sever now.all we are doing is just assembling tape library.Here is the picture of "HP surestore tape library model 20/700."
:)
Brian M Rawlings
Honored Contributor

Re: L20/700 :(

Wayne: good info, this makes sense now. I would expect the FC to be connected into a SAN, rather than to an individual server or servers.

Note that there is HVD UltraSCSI, some of my earlier info should be discarded if that is in use for connections. I was under the impression that the FC->SCSI bridge cards simply put out LVD SCSI, which would be Ultra80. If there is HVD, it is probably for the Robotics, and you don't have anything to worry about except cabling it up right (HVD output to Library SCSI port). I am not sure of these details, unfortunately, you should probably talk to an HP CE or SE who has installed this or another 20/700.

You are very close here, and I think you have most of the info you need. FC-to-2-SCSI connections is a good scheme that will not bottleneck your data, it can handle the fast drives you've got.

Good Luck!! --bmr
We must indeed all hang together, or, most assuredly, we shall all hang separately. (Benjamin Franklin)