Re: tcopy tape to tape WAY too slow

From: Dan Nelson (dnelson_at_allantgroup.com)
Date: 03/30/04

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    Date: Tue, 30 Mar 2004 09:39:33 -0600
To: Jesse Guardiani <jesse@wingnet.net>

    In the last episode (Mar 30), Jesse Guardiani said:
    > I'm copying 35G/90G AIT-1 tapes on FreeBSD from tape drive to tape
    > drive (nrsa0 and nrsa1) using the tcopy -c command and it's taking
    > WAY too long. Over 12 hours including the verification process. (not
    > sure exactly how long as it finished when I was sleeping)
    >
    > Is there something I can do to speed this up?

    I don't think tcopy is double-buffered; if you only have one file on
    that tape and know the blocksize, dd if=/dev/nrsa0 bs=##k | dd
    of=/dev/nrsa0 bs=##k should be much faster. If you have multiple files
    or unknown blocksizes, the cptp command from the MAG package at
    http://www.cs.vu.nl/~***/mag.html will preserve filemark and blocksize
    info through pipes, so you could do a cptp | cptp pipe. 

    -- 
	Dan Nelson
	dnelson@allantgroup.com
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