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.
