Date: Fri, 12 Nov 1999 10:20:30 +1100 From: Peter Jeremy <jeremyp@gsmx07.alcatel.com.au> To: Andrew Hodges <ahodges@ozemail.com.au> Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: Dump and SDT9000 Message-ID: <99Nov12.101437est.40349@border.alcanet.com.au> In-Reply-To: <01d401bf2c96$9943fef0$0303000a@kanine.emsvs.com.au> References: <01d401bf2c96$9943fef0$0303000a@kanine.emsvs.com.au>
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On 1999-Nov-12 09:46:31 +1100, Andrew Hodges wrote: >I have recently purchased a Compaq 12/24GB DDS3 DAT Drive If this is a TLZ10, then I use them here (with Digital Unix aka Compaq Tru64). >I think a re-badged Sony SDT 9000. I don't know, sorry. (DEC changed the INQUIRE strings and I haven't had a reason to pull any out yet). > Can anybody help me with the correct parameters for the >dump command for this drive ie buffer sizes etc? The I/O buffer sizes shouldn't matter too much. I use 64k. Unless you have a particular need for dump's tape-size calculations, I'd suggest using `-a' and let the drive complain when it's out of tape. (The calculations don't work when you have multiple backups on a tape or are compressing the data, in any case). One caveat: The DDS compression algorithm appears to perform very badly on compressed data - I found around 25% expansion - and doesn't seem to do a particularly good job on the sort of random text/binary data you're likely to find in a filesystem. I found I was much better off using gzip and running the drive in non-compressed (12GB) mode (assuming you've got the CPU horsepower to make this feasible). Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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