Date: Mon, 7 Apr 2003 10:03:39 +0200 From: Andreas Totlis <usenet@esct.org> To: Nathan Vidican <nathan@vidican.com>, freebsd-questions@freebsd.org Subject: Re: Problems with dump/capacity/DLT IV 40-80GB Tape cartridges Message-ID: <20030407080339.GC4265@baldur.asgard> In-Reply-To: <20030406144727.M85382@vidican.com> References: <20030406144727.M85382@vidican.com>
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Hello Nathan, I'm always fight with my SLR50 Tape Drive :-) * Nathan Vidican <nathan@vidican.com> [030406 16:49]: > sa0 at ahc1 bus 0 target 1 lun 0 > sa0: <BNCHMARK DLT1 391B> Removable Sequential Access SCSI-2 device > sa0: 20.000MB/s transfers (10.000MHz, offset 8, 16bit) > > Output of 'df' returns the following: > > Filesystem 1K-blocks Used Avail Capacity Mounted on > /dev/aacd0s1a 2064302 64488 1834670 3% / > /dev/aacd2s1e 70558134 4227862 60685622 7% /server > /dev/aacd0s1f 6132382 1363156 4278636 24% /usr > /dev/aacd0s1e 8257742 124818 7472306 2% /var > procfs 4 4 0 100% /proc > > The Problem: > ~~~~~~~~~~~~ > > When using 'dump -0au -f /dev/sa0 /server' I cannot fit the contents of > /server (approx 4.2gigs of data) onto a single tape volume. The tape > inserted is a brand new HP C5141F, (which is a 40/80GB DLT IV cartidge). > Dump prompts for a new tape to be inserted to complete the operation. I > assumed this had to do with the '-a' part in the dump command; assuming that > dump is therefore not (properly) auto-detecting the EOT (end of tape), or > using the wrong recording density and reaching the end of the tape all too > quickly. Using 'restore -i' I can indeed read the data written to the tape, > so it is writting the data... just not properly. > > The Question: > ~~~~~~~~~~~~~ > > Is anyone out there using similar hardware, or know of the proper arguments > to pass to dump to make full use of the capacity of these DLT IV cartridges? > I have checked HP's website, and these particular cartidges list a length of > 557Meters, and a density of 46.8K/80K/96K dependant upon 40GB/70GB/80GB > compression schemes. How do I formulate the dump command to properly make > use of these tapes.... any suggestions? Try to set the blocksize by your Drive(e.g.: "mt -f /dev/... blocksize 64" - see man mt). Set the blocksize in your dump command. My actually dump call: /sbin/dump 0aubf 512 - /mail | /usr/local/bin/team 1m 3 >/dev/nrsa0 Anymore you should use a buffer (e.g. team) to ensure that the Drive streams continous. hth Andreas -
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