Jay, thanks for all this info. I am able to run these dd commands successfully. So I'm beginning to think that amanda is the source of the problem. However, before I go any further, I'm extracting the data from the tapeimages to ensure that tar doesn't crash.
-Rob > -----Original Message----- > From: Jay Fenlason [mailto:[EMAIL PROTECTED] > Sent: Wednesday, April 07, 2004 5:20 PM > To: Dege, Robert C. > Subject: Re: AIT-2 > > > On Wed, Apr 07, 2004 at 01:23:53PM -0700, Dege, Robert C. wrote: > > > > > > > Can you take one of your backup tapes and access the files on it > > > reliably with dd? If you can't, it's likely to be a > hardware/os/etc > > > problem. If you can, it may be an Amanda problem. > > > > > > Is there any chane of bad termination on your SCSI chain? > > > > What would the dd command line be? > > Start with the tape rewound. > cd to a directory with a lot of space. (Up to 50Gb if you want to > read your entire AIT-2 tape.) > > dd < /dev/nst0 > tapeimage.1 bs=32k > dd < /dev/nst0 > tapeimage.2 bs=32k > dd < /dev/nst0 > tapeimage.3 bs=32k > dd < /dev/nst0 > tapeimage.4 bs=32k > dd < /dev/nst0 > tapeimage.5 bs=32k > dd < /dev/nst0 > tapeimage.6 bs=32k > ... > (Repeat the dd command until it creates an empty file.) > > The first tapeimage file will be the Amanda tape label. The last file > with data in it will be the Amanda tape end marker. The other files > will be the backups. If dd read all the backups and the end marker > successfully, any remaining problem is likely to be Amanda's. > > Each of the backups is going to be a (possibly compressed) dump output > file or a (possibly compressed) tar file. Either way, there's a 32k > header that you need to skip over to get at the actual data. If > they're tar files, you should be able to read them with > > dd < tapeimage.n bs=32k skip=1 | gtar tvf - > > If they're compressed tar files, you'll need > > dd < tapeimage.n bs=32k skip=1 | gunzip | gtar tvf - > > If they're dump files, I don't know how to read them. Check the > restore man page. > > > Right now, I'm running a tar command directly to a standard AIT-2 > > tape. I want to see if the problem is with tar, or with > amanda using > > tar. I'm tarring files to the tape, and then will try to > extract the > > files. I'm also using the same file chunk that failed on amanda to > > eliminate any additional variables in my test. > > > I don't think SCSI termination is the problem since I can use the > > tape changer without any problems, and backups occur > without error on > > a nightly basis. I'll double-check tough. > > If it's a hardware or OS problem, your tar test should find it. > > -- JF >
