Date: Wed, 24 Mar 1999 15:04:15 +1030 From: Greg Lehey <grog@lemis.com> To: Ian Moore <imoore@hamcoll.schools.sa.edu.au>, freebsd-questions@FreeBSD.ORG Subject: Re: Using dump with a DAT Message-ID: <19990324150415.W425@lemis.com> In-Reply-To: <36F81CD5.C5E6AB25@hamcoll.schools.sa.edu.au>; from Ian Moore on Wed, Mar 24, 1999 at 09:29:33AM %2B1030 References: <36F81CD5.C5E6AB25@hamcoll.schools.sa.edu.au>
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On Wednesday, 24 March 1999 at 9:29:33 +1030, Ian Moore wrote:
> Hi,
> I'm trying to dump to a Seagate CTD4004R-S 4/8Gig DAT drive on a server
> running 2.2 STABLE & am having problems when the end of the tape is
> reached. Using -u does not work.
Do you really mean -u?
-u Update the file /etc/dumpdates after a successful dump. The for-
mat of /etc/dumpdates is readable by people, consisting of one
free format record per line: filesystem name, increment level and
ctime(3) format dump date. There may be only one entry per
filesystem at each level. The file /etc/dumpdates may be edited
to change any of the fields, if necessary.
This doesn't really seem relevant to your problems. It seems like you
want to mean -a:
-a ``auto-size''. Bypass all tape length considerations, and enforce
writing until an end-of-media indication is returned. This fits
best for most modern tape drives. Use of this option is particu-
larly recommended when appending to an existing tape, or using a
tape drive with hardware compression (where you can never be sure
about the compression ratio).
The question is, which option did you try? -a sounds like the way to
go to me.
> I found this in the mailing list archive:
>
>> On Wed, 25 February 1998 at 16:01:21 -0600, Jason Hudgins wrote:
>>>>> I have a Seagate DAT that I've been dumping backups too. The DAT is
>>>>> supposed to have a 4 gig capacity (uncompressed) when writing to a 120m
>>>>> tape. Can anyone PLEASE tell me the proper density/tape length to get
>>>>> 4 gigs out of this thing? So far I've been using a density of 61000 and a
>>>>> length of 6000, which will store about 2 gigs..and works fine, but I
>>>>> REALLY need to get 4 gigs out of it...or at least 3.
>>>>
>>>> Try using the -a option and drop the length and density options. If your drive
>>>> reports EOM properly it should work just fine.
>>>
>>> I've tried that.. it doesn't work.. it just hits the end of the tape and
>>> the bugs out with write errors.. =(
>>
>> Unfortunately, the tape driver currently returns an I/O error
>> indication when it hits end of tape. They're working on it, but it's
>> more complicated than it appears.
>>
>> Greg
>
> I'm wondering if this problem has been solved yet?!
Hmm. It would have helped if you had included the date and the name
of the sender in your quote, but it appears to have been from me on
Thu, 26 Feb 1998 09:43:28 +1030. Yes, I'm pretty sure the software
has changed completely since then. But ISTR that dump doesn't take
kindly to end of tape.
> If not, can anyone tell me what values I should use for a 4G DAT tape
> (120 metres) if I don't use compression -I've tried some of the
> suggestions given on the mailing list archives, but keep getting
> 'invalid 'd' (density) value' or 'invalid 'b' (no of blocks per write)
> value' errors.
> There seem to be numerous opinions on what values to use & wether to use
> d & s or b & B parameters & I'm kinda confused.
If you're going to get involved in this kind of guesswork, then -b and
-B are the way to go, but you'll waste a lot of space if you turn
compression off, and I'd still go for -a. What error messages are you
getting?
Greg
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