Date: Mon, 21 May 2001 09:24:54 -0500 (CDT) From: mark tinguely <tinguely@web.cs.ndsu.NoDak.edu> To: nvidican@ipsnetwork.net Cc: questions@FreeBSD.ORG Subject: Re: erasing a tape volume, (or possible dump is broken?) Message-ID: <200105211424.f4LEOsZ95967@web.cs.ndsu.NoDak.edu>
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Nathan Vidican <nvidican@ipsnetwork.net> types: > I tried to do another zero level dump this evening, on a tape which I > had previously used for a zero level dump. It dumped about 1.8gigs, and > then asked for the second tape volume; the drive is a DDS-2 > (4gig/8compressed) internal Seagate SCSI DAT. I used the command: dump > -0au /server; when I do a df, the partition /server has only got about > 2.1gigs used (out of a possible 4.3 on a RAID array (mirrored via > hardware controller), so I know it shouldn't be a capacioty issue). What > I'm not sure of though, does dump over-write what's on a tape, or append > to it? If the latter is true this would make sense; but if not then how > exactly to I force dump to either overwrite with a new volume on the > tape each time, or erase the tape beforehand? Another possible problem beside Mike's observation that you could be using the non-rewinding tape device is tape streaming. If the data is not being fed to the tape device at a fast enough rate the tape drive may be stopping and you will not get the maximum amount of data stored on a tape. Lack of streaming significantly reduces the amount you can store on a tape. Many times hardware compression is a jumper setting on the back of the tape drive. --mark tinguely To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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