Networker

Re: [Networker] Troubleshooting a tape drive

2007-08-03 17:52:24
Subject: Re: [Networker] Troubleshooting a tape drive
From: Stan Horwitz <stan AT TEMPLE DOT EDU>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Fri, 3 Aug 2007 16:45:24 -0400
On Aug 3, 2007, at 12:18 PM, Davina Treiber wrote:

Stan,

In the absence of a vendor supplied kernel for this issue, you need to enter into the true spirit of Linux, and build and install a patched kernel.

You will need to install the kernel sources RPM. The file you need to modify will be something like /usr/src/linux/drivers/scsi/st.c. You will then need to configure and install the kernel for your system. Probably slightly easier said than done, but at least there is plenty info on the web about how to configure and build a custom kernel.

Thanks Davina and Tim. On the basis of Tim's email, I tried to get the kernel source and modify it. Unfortunately, I have less than a clue about what I am doing, even with the web page that Tim pointed me to. Since my manager ("Mr. Red Hat Linux will solve the world's problems") insisted I use RH Linux instead of Solaris, I will hand this part of the project to him when he returns from the black hat conference and have him show me how to do this.

Oddly enough, I think I got it partially working. I can label tapes without growing too much older. In addition, "nsrjb -C" comes back with accurate information after about ten minutes, which is slower then I prefer, but not as slow as I have seen on a heavily loaded older server I used to have. I also kicked off "nsrjb -U50 -S1" to set up a cleaning tape (yes, I have it in the first slot) and its still sitting there after 15 minutes. I can also see that nsrjb will mount/unmount tapes in all tape four drives, fine now, albeit slow.

I was also able to backup of this Linux server, itself and recover files from the backup. After mounting a tape, it gave an I/O error on the tape I manually labeled, but its writing to a tape now that it labeled on its own after I switched on the auto media management feature, although the throughput is only around 5-10MB/s, which is certainly way too slow for direct attached LTO-3 devices. Sigh!

In the meanwhile, I am going to try backing up one of our large servers to it and see what happens.

--
Stan Horwitz
stan AT temple DOT edu

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