topic Re: DLT4000 tape drives in Operating System - HP-UX

DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 07:19:29 GMT

I have a K460 running 11.0 and have 2 DLT tapes drives hooked to it. I had one go bad, so I hot swapped it out with out realizing I could not do that. I ended up shutting down, power off box, power on, but system still doesn't open or identify the tape drives.
Where do I go from here?

Re: DLT4000 tape drives

Pete Randall — Tue, 29 Aug 2006 07:25:50 GMT

Check for SCSI ID conflicts. If you need to change the ID, you will have to power cycle the drive in order for it to take the new ID. Then do your ioscan and you should see the drive.

Pete

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 07:38:16 GMT

I am new at this - what are some of the commands to do this?

Re: DLT4000 tape drives

DCE — Tue, 29 Aug 2006 07:47:50 GMT

Linda

ioscan -fnC tape
will list the available tape drives

you should see the drive and the device files
(i.e. /dev/rmt/0m)

If you have a SCSI address conflict, then you will not see one or both of the drives in listing

To change the SCSI address you have to physically move a setting on the actual drive. Look at the two drives in question and find out if they are both set to use the same number. If so, power down the system and change the setting on the "new" drive, then power up

Re: DLT4000 tape drives

Pete Randall — Tue, 29 Aug 2006 08:13:55 GMT

Linda,

Since the system can't see the drive, there are no commands. You have to physically look at the back of the drive to see what the SCSI ID is set to. There's a little window with a plus and a minus button. I would suggest making sure that the ID in the window is set to the same number as your previous drive. If you don't know what the previous drive was set to, you will need to analyze ioscan output looking for the SCSI IDs of devices on the same path as the drive to make sure you're not duplicating.

I have previously swapped these out "hot" and never had any problem. The symptom you describe simply screams SCSI ID conflict!!

Pete

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 08:27:00 GMT

The old drive was set at 4, so that is what I set the new drive as. The other has 5 on the back

Linda

Re: DLT4000 tape drives

Patrick Wallek — Tue, 29 Aug 2006 08:30:09 GMT

You need to power the drive off and back on for the new id to take effect.

Then try an 'ioscan -fnC tape' and see what output you get.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 11:39:39 GMT

Re: DLT4000 tape drives

A. Clay Stephenson — Tue, 29 Aug 2006 11:42:06 GMT

Are you certain that the replacement DLT4000 drive is compatible? Specfically, do you know that it is a HVD scsi device because not all DLT4000's are? If you installed a non-HVD device on an HVD SCSI bus then you could have damaged the HBA, terminators, and any other devices on the bus. Normally, while certainly not recommended, hot-swapping external tape drives does not cause problems or damage equipment. I do it rather routinely to replace failed tape drives as long as only tape drives are on the bus and that the bus itself is idle at the time. Have you made certain that the bus is properly terminated -- at the physical ends of the bus? It's possible that you have enabled termination on a drive in the middle of a bus. It's also possible that you blew the termination power fuse on the HBA --- that's not uncommon especially if the pins might be slightly bent. As a matter of course, I would check each connection for bent pins. It's really easy to bend a few on these connectors.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 11:53:44 GMT

I have the cable form the HP box to the bottom connector of one drive, then a cable from the top connector to the top connector of the second drive (the one I replcaed), then a terminator on the bottom connector fo the second.
I have already checked the pins and none are bent.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 12:59:08 GMT

I asked my supplier and they are suppose to be HBV

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 13:16:27 GMT

sorry - HVD is what I meant

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 13:31:42 GMT

If I blew the fuse on the card wouldn't it show amber light instead of green, or not show at all. Ioscan sees the card yet.

Re: DLT4000 tape drives

A. Clay Stephenson — Tue, 29 Aug 2006 13:49:35 GMT

10/16/12.7 unknown --- This entry looks extremely suspicious because it implies that another controller is on this bus. Is that the case? I note that your HBA's SCSI ID is set to 6 where it is normally 7 --- again, unless there are two controllers on this bus.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 14:02:08 GMT

The DLT drives are daisy chained.
Linda

Re: DLT4000 tape drives

A. Clay Stephenson — Tue, 29 Aug 2006 14:24:45 GMT

Oh, and you have way too many devices on this bus. The maximum number of DLT4000's on a HVD/FWD bus is 2. That will completely saturate the bus. If DLT's are not supplied with data fast enough to allow them to stream, the throughput drops but a factor of 100 or so. Normally DLT's are installed on a dedicated bus. This isn't your problem at the moment but you are going to be very disappointed in performance if, and when, you get the drives recogized.

The Green TERM PWR LED on the 28696 indicates that the fuse is not blown. I assume that you have the stape and scsi3 drivers "In" the kernel.

Re: DLT4000 tape drives

DCE — Tue, 29 Aug 2006 14:31:43 GMT

unknown usually implies that the stape or scsi driver is not in the kernel. Did someone regen the kernel and remove the driver? (the kernel does not recognize the tape drive - hence unknown)

The usual practical limit for high spped tape drives per bus is two - even that sometimes adversely impacts backup speeds. You may want to consider reducing the number of devices on this channel.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 14:33:30 GMT

I only have the 2 DLT's daisy chained together.
This is how it has always been. I am going to shut the system off, unhook the daisy chain, terminate the one connector, turn system back on to see if I can at least have one good tape drive to do my backup.

Re: DLT4000 tape drives

Linda Lux — Tue, 29 Aug 2006 14:41:36 GMT

stape and scsi3 are in the kernel
Linda

Re: DLT4000 tape drives

A. Clay Stephenson — Tue, 29 Aug 2006 14:45:31 GMT

My ioscan looks like this:
10/16/12 ext_busHP 28696A - Wide SCSI ID=6
10/16/12.0 unknown
10/16/12.1 unknown
10/16/12.2 unknown
10/16/12.3 unknown
10/16/12.7 unknown
10/16/12.8 unknown
10/16/12.9 unknown
10/16/12.10 unknown
10/16/12.11 unknown
10/16/12.12 unknown
10/16/12.13 unknown
10/16/12.14 unknown
10/16/12.15 unknown

If you have only 2 DLT4000's on this bus then something is very wrong. You are seeing far too many devices. I would not make the assumption that the external thumbwheel switchg that is used to set the SCSI ID is actually connected to the drive. If that were left uncoonected on either drive then the SCSI ID is indeterminate. It might even be hard jumpered on the drive itself so that just because you don't think you have a SCSI ID conflicts doesn't mean that you don't have one. If this is a single HBA bus, then your 28696's ID should be set to the highest priority, 7.