MSL5000 2 LTO2 Drive Cabling/Configuration

[Mikecl]

We have upgraded the LTO1 drives to LTO2 in our MSL5000 library. The docs say the 460 drives should not be connected to the same scsi bus for performance reasons. I have a fibre router installed and no scsi connections to machines. How should I connect/configure the drives for maximum performance. The diagrams I have seen are for multiple hosts etc but not for our scenario.

[Jacob Zeeman]

Hi Mike,

I've included an attachment of how the two drive library should be configured. In the 4 drive library the bottom two drives should both be cabled to the NSR, in the same way as the drives in the 2 drive library. Except that no cable needs to go to the library control module, and both bottom drives will need to be terminated.

[Mikecl]

Hi Jacob,

Thanks for responding, Not sure If I made myself clear I swapped out the two LTO1 drives for LTO2 drives. I have my cabling as attached. On the tape lib front screen I can see the two drives ok however when I check the drive status
LTO Drive 0 speed says Ultra80 & on SCSI bus yes

LTO Drive 1 SCSI speed default & on SCSCI bus no.

I have previously run tape tools and the diags run ok but when I used the lib for backing up in earnest it will only backup to one drive.

[David Ruska]

Mike,

The cabling looks correct. You have a single drive on one of the NSR SCSI busses, another drive and the library controller on the other bus, and both busses are terminated.

What version of firmware are you running in the library, NSR, and drives?

Can you generate a report page output from the MSL web management GUI?

[Mikecl]

Hi David,

The Tape drives are F59W 007.646 Tape Lib 5.13

I have attached the report

[Mikecl]

Sorry the attachment seems to be missing I have reposted with the attachment.

[Mikecl]

Hi

I have reconfigured the tape library and it can see the second drive and it is on the SCSI bus. I ran two test backup job which ran on different drives ok but when the nightly job runs it only uses one drive, when I check the tape library it shows the second drive not attached to the SCSI bus?

Any Ideas?

[David Ruska]

Mike,

Thanks for your updates. Sorry for the delay in responding.

When I asked for a report page, I was confused with the web interface on the NSR router. The only thing similar on the MSL itself is the "full drive status" screens, which you captured.

I will have to research the "On-bus" configuration information. It's not mentioned in the user or service guides.

In our previous l-series libraries, the "on bus" parameter indicated the library controller was on the same bus. However, I checked two similarly configured MSL libraries in our lab and both had "On Bus" set for both drives regardless of whether the robotics were on the same bus or not.

One way to test if your host is seeing both drives consistantly would be to install HP Library & Tape Tools (www.hp.com/support/tapetools). It should discover and associate both drives to the library. You can also run a r/w test on both drives in parallel.

With LTT installed, we could also collect a library support ticket to look at the error logs for any clues.

I'll let you know what I find out about the "On-bus" configuration.

[Mikecl]

Hi David,
If I reboot the library or fibre router both drives indicate on the SCSI bus. If i use tape tools it normally checks out but If I run it after the fault it complains of not being able to read data from the drive which is understandable. I have moved the tape devices on the fibre router mapping (Library still at top) and within windows(w2k3) the tape drive LUN's change but always on the one SCSI bus. If I run a test job it sometimes works ok but when I run our nomal backup cycle all the jobs run on the other tape drive (apart from the one that fails on the drive in question) Insight manager sends an alert and the backup exec 10 Job fails details are in the attached file. I replaced the SCSI cable to the drive in question yesterday but it made no difference. I will try running the tape tools r/w test concurrently. One thing I did not check was the jumpers on the tape drive itself should there be any difference between the two drives?

[David Ruska]

Mike,

From your updates, it appears that something is happening in the mapping of one of the drives to the fibre channel side.

You mentioned insight manager. Are you running the insight manager agents? If so, there's a known issue with versions 7.20 and below.

Also, there are two possible issues with W2K3 that could cause problems. Is Windows Removable Storage Manager (RSM) service disabled (assuming your backup app does not utilize RSM)?

The other issue is a Test Unit Ready polling issue from W2K3. I'll have to look up the info on that.

I'm still waiting for engineering to get me an answer regarding the "On-bus" configuration.