SCSI Compatibility ultrium 230

[Alfredo Moralejo_2]

I'm having problems whith a HP Netserver LH6000 with w2k, atached to a tape array 5500. The scsi card is a p3413a (adaptec 29160, ultra3). i'm trying to connect three ultrium 230 drives in daisy chain. Connecting one slot at a time, all works fine (only one drive), but if i dasy chain 2 of them, it fails when i try to do a backup. i've replace drives, cables, terminator, whole tape array and scsi card and the behaviour is caotic. I think there must be a problem whith the scsi ultra3 specification.
please help!

[Vincent Farrugia]

Hello,

I'm sorry but you cannot daisy chain Ultrium drives.

HTH,
Vince

[Alfredo Moralejo_2]

Can you give me a link or something like that to justify it to the customer?

[Vincent Farrugia]

Hello,

Follow this link:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?locale=en_US&taskId=8415&taskName=discover+%26+use+your+product&prodSeriesId=42921&prodTypeId=12169&prodSeriesName=hp+surestore+ultrium+230+drives&docId=81957

HTH,
Vince

[Mike Kramer]

If they can't be daisy-chained why is there a 2nd port on the back of the Ultrium 230 drives which the manual says is for daisy chaining? Just curious. With the drives negotiating at 80 MB/s, and the scsi adapter capable of 160 MB/s, you should be able to have 2 drives on there without a decrease in performance.

[harry d brown jr]

If a drive has the ability to run at 80mb/s (that's 80 mega-BITS a second) on a 180mb/s bus, does not mean you can have two devices on it running at full speed. Think of it like a race track. If two drivers are speeding around the track they could interfer with each other causing them to slow down. And, besides those "published" numbers don't mean a whole hell of a lot because those numbers are NOT real world numbers, they are theoretical.

live free or die
harry

[Mike Kramer]

Harry D Brown,

Let's see, I'm not trying to be picky, but I don't want anyone reading this to have the wrong information. The drives actually have the ability to run at 30 MB/s assuming 2:1 compression, (that's 30 MEGA-BYTES a second) even though they negotiate at 80 MB/s (that's also MEGA-BYTES a second), you listed 80mb/s (that's actually 80 micro-bits a second since you used a small m). The 29160 cards can handle 160 MB/s (THAT'S STILL MEGA-BYTES PER SECOND) which actually means you could put 5 Ultrium drives on 1 channel without losing performance. It's very good you pointed out the theoretical or published vs. real-world, although the transfer rates usually decrease because of target servers and tape drive performance, not usually from the local SCSI adapter. What this means is I wouldn't worry about having 2 Ultrium drives on 1 29160 card, but simply because of the amount of I/O requests spewing from the card to the CPU, I wouldn't count on running more than that unless you had a really beefy server.

[Leif Halvarsson_2]

Hi
If you daisy chain two (or three) drives, can you use one of them at a time or does this problem only apply if you try to run both (all) simultaneous. I have not tried daisy chaining LTO devices but I don't think this is very different from other tape devices. If the SCSI bus is fast enough (80 or 160 MB/s) it should be possible to connect more then one drive to each bus. And, if you only use one drive at the same time it should be possible to connect more then one drive to a 40MB/s SCSI too.

[Scott Vintinner]

I had this same problem. At my company, we didn't care about performance, we just needed to back up 300 gigs of data and didn't want to have to change tapes or deal with the hassle of a tape library.

I spent about a month working with HP on this problem. They sent me a new tape array as well as new tape drives. The new devices had the same problem as the old. In the end they decided that my problem was that I was running Dell Poweredge 2550 servers, which they considered "pizza box" servers.

I told them that I have a Dell Powervault that is essentially 2 Ultrium drives daisy chained together on a single SCSI bus, and it works on that server, but that didn't phase them.

I've also found that the Ultrium drives in the tape array can be very chaotic. A single drive (not daisy chained) may or may not work with a different combination of scsi cards and cableing. Specifically, the only SCSI card I've been able to get it to work on is an adaptec 29160 with an external wide 68 pin LVD connector and the adaptec cable. Trying to hook the same system up to a 29160LP with a 68-pin VHDCI connector using an HP cable doesn't work. (Personally I think this issue is related to the daisy chaining issue, since that is VHDCI->VHDCI and it fails to work as well).

[Scott Vintinner]

Actually I think I just solved my problem. Adaptec just released a new driver for their adaptec 29160 on Nov 8 2002. The readme for the new version includes the text:

-------------------------
Windows 2000:

ADPU160M.SYS, ADF6U160.SYS

Fixed Issue:

1.With non-disk device such as HP Ultrium Tape drive, the driver did not negotiate transfer rate, all subsequent IO transfers occurred as Async.

2.Tape IO Test certification failure fix.


After installing this new driver, I am now able to backup perfectly using the Ultrium drive.