SUMMARY: SCSI mode degrade problem

From: Rongsheng Fang <>
Date: Tue Feb 08 2005 - 09:52:53 EST
Thanks to those who kindly responded: David Foster, Michael Horton, Tom
Grassia, Tim Evans, Ray Pengelly, joe_fletcher.

My question was:

> We have a L25 tape library hooked to a v880 running Solaris 8 (both
> L25 and the SCSI card on the v880 are HVD). We have been having
> problems with power-cycling the L25 since we started using it:

> 1) Everytime after we power-cycle the L25 library, the SCSI mode will
> degrade and the write speed of the tape drives will drop from 12Mb/s
> down to 3Mb/s. We can only bring the SCSI mode back to normal by
> rebooting the machine.

> 2) After rebooting the machine, the tape drive speed will get back to
> normal again (about 12Mb/s).

> My question is: how, other than rebooting the machine, can we bring
> the degraded SCSI mode to normal? Any idea why the SCSI mode degrades
> whenever we power-cycle the L25 tape library, or has anybody ever
> encountered this kind of problem?

> Many people wondered: why are you power-cycling the L25 so often?

> Because sometimes a tape gets stuck in the tape drive and we cannot
> get it back to the slot even using L25's 'move' from the panel. We
> have to power-cycle the L25 to get the tape library back to the normal
> state and get the stuck tape out. That's the only way I know. Do you
> know of any other ways that can do this?

David Foster replied:

Power-cycling the library may be causing some sort of scsi bus
reset or something.

One workaround is to use 'devfsadm -c tape' to try and rebuild
the device files for the library, which is presumably what a reboot
is doing.

RESULT: Tried this and it didn't work.

Ray Pengelly replied:

Have you tried using cfgadm to disconnect/reconnect/configure the
controller before/after the reboot.

cfgadm -al ---lists all devices and controllers.
cfgadm -c disconnect c2 ---disconnects controller 2
cfgadm -c connect c2 ---reconnects controller 2
cfgadm -c configure c2 --reconfigures contoller 2

Only use this if it's the only device on the SCSI bus!!!! Read the
cfgadm manpage for more info.

RESULT: I was trying to avoid reboot to get the SCSI bus reset. But
anyway disconnect/connect didn't work in this case (v880+L25).

joe_fletcher replied:

Recommend as far as possible that you keep the firmware on the L25 up to
date.  If you don't you can end up with all sorts of issues with
translation unit errors, calibration problems and so on.  Make sure the
glm SCSI drivers are up to date as well.

What you might try as a fix is to deconfigure the adapter then
reconfigure it.

cfgadm -c unconfigure c?  (where ? is the number of the controller)
cfgadm -c configure c?

RESULT: tried this and it didn't work.

I tried all the solutions suggested above but unfortunately none worked.
If anybody has any other suggestions, please let me know and I will try
them out.


Rongsheng Fang
sunmanagers mailing list
Received on Tue Feb 8 09:53:13 2005

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