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Re: Tape Library drive-1 stucks frequently (MSL6030)

 
rana786
Regular Advisor

Tape Library drive-1 stucks frequently (MSL6030)

Hi All,
MY MSL6030 tape library with 2 drive 460 ultrium fc san environments having problem in one drive only once in a week. It gets stuck once in every week during taking backup on Friday. Normally all important backup have been taken on Friday as this is our weekend day.
The problem arise when the unmount operation start in drive 1 (not all time). It canтАЩt unmount the tape form drive 1 but at that time drive 2 works fine.
After rebooting the tape library it works again properly for up to next Friday. So what is with the Tape drive? I think the drive is becoming stuck getting overloaded. L&TT can not find problem? Can anyone help me with this issue?

HP-UX, Linux, & Windows hosts are connected to this Library through SAN.
Walker_dhk
11 REPLIES 11
Dylan W
Advisor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Hi Rana

I work with these libraries daily, and I find it strange that these stuck tapes would always occur on friday. I have a few questions. On what day do you input and export tapes to the library? Is the library set for sequential backups, or do you set your backups to write a certain amount per tape? Do you have the library cabled to look like this diagram?

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c00659626&jumpid=reg_R1002_USEN

Let me know if this helps :)

Dylan
rana786
Regular Advisor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Hi Dylan,

The drive 1 of the library is not getting stuck only on Friday. I mean this drive gets stuck during unmounting cartridge and it may happen any day during taking backup. As most of our schedule for backup is on Friday that is why it stucks often on Friday. Its happening on the other days as well. Whenever it stucks I have to mannually restart the library and it works fine for a few days.
1)We closely monitor all backups when any cartridge gets near full then we replace it. There is no schedule for doing that.
2)We have both sequential (scheduled) and non-sequential (mannual) backup. I have some core backup if needed we run somescript for triggering backup.
3)Cable layout is ok.

Please help
rana786
Walker_dhk
Marino Meloni_1
Honored Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

you can have this behavior when the drive loose communication with the host. in this case the tape appear stucked because it was set "reserved" from the host, and if the communication has been lost, the only way to recover is a hard reset of the drive, this will clear the flag and allow you to eject the tape.
Now you need to investigate what can cause the host to lost the drive, this may due to several causes, like i/o error on the scsi path, other software polling the device, bad cable or terminator, defective Drive, power issues, etc.

you should check all the environment to identify the cause
Bill Costigan
Honored Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Does the backup work right up until the unmount or does the tape drive report a I/O error and then the host tries to rewind and unload the tape and those operations fail also?

I've seen this on SAN attached tape drives when another node (not even involved with the backup) sets the SCSI reserve bit on the drive.
avik
Valued Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

also is this behavior specific to any particualr server's backup or media ?
rana786
Regular Advisor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Hi all,

Yes, the backup works right up until the unmount. It shows an error

"Fault Code: 200F (Soft)
Removal Prevented"

in the OCP and then the host tries to rewind and unload the tape and those operations fail.

How can I get rid of unnecessary scsi reserve bit on the drive?

This behavior is not specific to any particualr server's backup or media. It happens only during heavy workload. It is not happening during normal workload. Please help.

Rana
Walker_dhk
Bill Costigan
Honored Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

At this point I do not think it is the scsi reserve. The reserve bit would prevent any I/O from completing.

I also assume you cannot unmount the tape from the front panel until you power cycle the libray. Is that correct?
Bill Costigan
Honored Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Check out this http://forums2.itrc.hp.com/service/forums/questionanswer.do?threadId=876699

It seems that this can be caused by a command being sent from another server.
Bill Costigan
Honored Contributor

Re: Tape Library drive-1 stucks frequently (MSL6030)

Do you have windows servers that have the tape driver enaable and can access the drive over the fiber? If so I would try disabling the tape drivers on those server and see if the problem goes away.