Re: [Networker] SCSI problems -- How many drives to a bus?

Whatever is causing the scsi resets is probably causing you to lose the arm.

The Legato manual indicates that scsi resets can cause the drives to unload
tapes, even when backups are running.

Some cards pass thru scsi resets, some allow you to block the scsi reset, so
if a device resets, it doesn't affect everything on the bus.

It's been a number of years since I had to diagnose scsi problems. There
should be software with the card that allows for running diags to determine
what is causing the reset.

Good luck

Paul Langford

-----Original Message-----
From: Lemons, Terry [mailto:lemons_terry AT EMC DOT COM]
Sent: Friday, January 09, 2004 1:47 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] SCSI problems -- How many drives to a bus?


Hi George

According to http://www.pcguide.com/ref/hdd/if/scsi/confIDs-c.html, the SCSI
device priority order is (highest to lowest) 7, 6, 5, 4, 3, 2, 1, 0, 15, 14,
13, 12, 11, 10, 9, 8.  7 is usually the SCSI HBA itself.  Your L80 picker is
set to SCSI address 6, which is the next highest priority.  Then again, your
picker is the only other device on the bus, so I don't think this could be
the problem.

tl



-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTMAIL.TEMPLE DOT EDU] 
On
Behalf Of George Sinclair
Sent: Friday, January 09, 2004 3:02 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] SCSI problems -- How many drives to a bus?

That's exactly what's happening. At some point the picker is no longer
seen by the software. It seems random. We might go several days before
seeing it again. Get these "aic7xxx_abort returns 0x2002" messages. This
doesn't always cause a faliure, though, but when the failure occurs, you
can bet that there was one of these SCSI resets that occured prior or
somewhere around that time seen in /var/log/messages.

How do we determine if the arm has the highest priority? How do we give
it the highest priority?

We had it daisy chained to drives 1 and 2 which were using channel A on
the Adaptec dual channel card and drives 3 and 4 were daisy chained and
used channel B. I since put the arm on its own bus so it now connects to
channel A on its own card and the drives still used A and B on the other
card as before. I terminated where the picker was daisy chained on back
of library. Here's current output from inquire:

[email protected]:SEAGATE ULTRIUM06242-XXX1522|Tape, /dev/nst0
[email protected]:SEAGATE ULTRIUM06242-XXX1522|Tape, /dev/nst1
[email protected]:SEAGATE ULTRIUM06242-XXX1522|Tape, /dev/nst2
[email protected]:SEAGATE ULTRIUM06242-XXX1522|Tape, /dev/nst3
[email protected]:ATL     P1000    62200502.23|Autochanger (Jukebox),
/dev/sg4
[email protected]:QUANTUM SuperDLT1       2323|Tape, /dev/nst4
[email protected]:QUANTUM SuperDLT1       2323|Tape, /dev/nst5
[email protected]:STK     L80             0212|Autochanger (Jukebox),
/dev/sg7
[email protected]:MegaRAIDLD 0 RAID1  139G1.92|Disk, /dev/sg8
[email protected]:PE/PV   1x8 SCSI BP     1.1 |Processor, /dev/sg9
[email protected]:HL-DT-STRW/DVD GCC-4240ND110|CD-ROM, /dev/sgk

George

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