Date: Mon, 6 Oct 97 10:41:49 -0400 From: curt@kcwc.com (Curt Welch) To: freebsd-isp@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Cc: curt@kcwc.com Subject: Re: Tape Backup Message-ID: <9710061441.AA04878@mail.kcwc.com>
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Philippe writes: >Chuck writes: >> > Khanh Nguyen writes: >> > > Does FBSD-2.2.2-REL support Hewlett Packard Colorado T3000 tape >> > > backup devices? If so, has anyone configured the kernel to use this? And >> > > if yes, can you send me the copy of the kernel config? >> >> > We're talking about the Travan SCSI HP/Colorado, right ? I have an HP Colorado T4000s. It's a SCSI drive which uses TR-4 tapes. I have two of them. Don't know what the guy above was talking about. >> > There was some talk about this drive some time ago, and IIRC, >> > it has a problem with tape locking or something like it (i.e.: >> > the Travan doesn't support it, and any operations to access the >> > drive fail miserably). Last time I checked the archives, no >> > no patch is available. Maybe check the Linux code (don't know >> > if they support it). >> >> Alas, as I found out, non-SCSI tapes of all stripes remain unsupported >> under FreeBSD-2.2.2 :-( So I forked over 3 bills and bought a TR-4, >> installed it as /dev/st0, and bingo, it goes like a champ, around >> 500KB/second! > > I thought the T3000 was scsi (travan). > What tape format does the TR-4 use ? > 2 quesions; My TR-3 machine is an Exabyte Eagle, straight > ISA, with its own board. Very nice if you run Micxxxxft > OS, but unsupported in FreeBSD. There may also be a SCSI > version. The TR-4 is apparently different. The > cartridges look identical, but the TR-3 says 1.6GB, while > the TR-4 says 4GB. Plastic, with an aluminum plate on > one side. The format is evidently multiple passes end > to end, with the head moving a tiny bit between passes, > just like the old tapes. No, it's not multiple passes. It's a single pass format. And yes, it holds around 4GB (uncompressed). I think it just has some huge number of tracks - something like 75. I get around 450 KB/sec. You have to use fairly large block sizes to keep it streaming (32KB works for me). Also, you get error messages from the kernel everytime you access the drive. This is fixed by changing a line in /sys/scsi/st.c (around line 436): (someone on the net posted this fix) scsi_prevent(sc_link, PR_PREVENT, 0); /* who cares if it fails? */ To: scsi_prevent(sc_link, PR_PREVENT, SCSI_SILENT | SCSI_ERR_OK); This just makes the kernel not complain about a command that the T4000s doesn't support. This "fix" doesn't make the drive work any different, it just keeps the kernel from printing the message. >> Alas, over an ethernet from another FreeBSD 2.2.2 system using dump, >> it hiccuped continuously, getting just about 50KB/second. I had a similar problem that turnd out to be the ethernet card I was using. It seemed to work fine, but if I did large ftp's etc it would slow to a crawl. I didn't notice the problem until I tried to do an rdump. Make sure you problem is not your network. Do some large ftp's or rcp's and make sure you get the transfer rates you expect. Curt Welch http://CurtWelch.Com/
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