On Sunday 18 September 2005 12:27, Florian Lengyel wrote:
>Jon LaBadie wrote:
>>On Sat, Sep 17, 2005 at 11:25:48PM -0400, Florian Lengyel wrote:
>>>Here's the post-mortem: I've been using a hand-me-dowm
>>>Spectra Logic 2K. No matter what tape I tried in drive 0
>>>(the only one of two that my AMANDA configuration seems
>>>to recognize) I had I/O errors. Even an innocuous command such as
>>>
>>>mt -f /dev/nst0 compression off
>>>
>>>[by the way, the argument "off" is worth a small fortune in
>>>consulting fees, since it has to be guessed]
>>>
>>>Resulted in an I/O error. Such things are often caused by
>>>hardware trouble. After checking cables, interface card seating,
>>>and other things, I tried using the cleaning tape.
>>>
>>>Problem solved.
>>
>>You wouldn't think a 'compression off' request would have
>>any involvement with possibly dirty heads.
>
>Well, the advice is to let AMANDA do its compression; without
>compression the drive is presumably going to be doing more work.
>I wasn't mentioning compression in that connection; I meant to
suggest
>by example that no matter what I did, I was getting I/O errors.
>Also, in the UNIX documentation I've seen, the mt compression
operation
>is described, but the "off" flag is not. I've searched in vain for
>this--made a career of it, in fact. I believe there was one obscure
web
>page on this, in Latvian.
>
Chuckle... Thats a SWAG of course, or do you read Latvian?
>> Here is a guess,
>>I've seen some tape drives that when an error happens flag
>>the error and refuse to do anything until it is cleared.
>>At one client they had a DLT drive. Anything went wrong
>>and the "clean drive" light came on. Then you could do
>>nothing unless you cleaned it or 'I think' there was some
>>manual way to turn off the light. Maybe power off/on :)
>
>The Spectra Logic 2K's changer LED did turn a jaundiced, tape-weary
>amber. Power cycling the drive did nothing. Only the wildly
inspired
>guess of inserting the cleaning tape helped. RTFM time, especially
>since the spectral logicians at Spectra Logic won't discuss my 2K
>without a service agreement.
>
>>BTW you mention you have other ?drives? not being seen?
>>Based on replies here, most linux kernels default to only
>>scanning LUN 0 on the scsi buss. Some configuation change
>>lets it scan others. Similarly on my Solaris system, by
>>default only scsi IDs 0-7 are scanned for tape drives.
>>Again a config setting allows IDs 8-15 to be scanned.
>>
>>Maybe something similar is your problem.
>
>I have a lot of problems; on the subject of tape backup, the Spectra
>Logic has two internal drives. The mtx command sees both (and numbers
>them 0 and 1), and the kernel appears to see both. However, Gene
>Heskett, in an email after this one, mentions that Red Hat doesn't
>bother to scan for both SCSI drives. I may have told a fib: I'm using
>CentOS on my AMANDA server. Perhaps I should punish CentOS and
install
>Debian instead.
Naw, Centos should be fine IF you've installed the kernel srcs too.
And I didn't say RedHat doesn't scan all addresses, they do, but they
do not scan all Logical Unit Numbers, there being (IIRC) 8 unique
LUN's per scsi bus address.
That being the case, one could fnd a .config in that kernels
scripts subdir, move the correct one to the root of the kernel tree,
do a 'make oldconfig' followed by a 'make xconfig', find the scsi
stuff and turn that "SCAN_ALL_LUNS" option on, then rebuild and
re-install. Maybe as simple as a 'make install' if the Makefile is
fairly recent.
But, if using Centos, are you using their often outdated amanda rpms,
or building amanda from scratch, which is what the huge majority of us
recommend. Other than using the FILE driver now instead of the TAPE
driver, I've been using the same script to configure and build amanda
as each snapshot is released for 4 or 5 years now. By having all the
options in a script, each succeeding version simply slides into place
with a 'make install' as root after running the script to build it as
the user amanda, followed by a quick 'ldconfig' to bring all the
library links into order. I usually have it built and installed the
same day as the release, so I am able to function somewhat like the
canary in the coal mine, reporting any breakages before too many get
burnt. 2 such cases in 5 years speaks very well of amanda I think.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.35% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
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