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Re: Ecrix Tape Drive on OpenBSD?



Mike Darweesh <jaromir_(_at_)_Radix_(_dot_)_Net> wrote:

> I haven't tried that specifically because I'm told that dump is better due
> to blocking organization.

No.  dump is better because
- it reads from the raw device and can thus recover exactly what's on
  disk (think sparse files) and doesn't change access times,
- it's archive format isn't as limited (long file names, file flags,
  etc),
- it creates an index at the start of the archive which allows for
  browsing archive contents without having to read back all the archive.

> I'm going to give dump another try with a different density and then
> try the commands specifically on this web page to see if I can get closer
> to 33G

Early on, dump gives an estimate of the size of the tape archive.
You want to compare that to the tape capacity, rather than filesystem
usage.  You also might want to check whether those "33GB" are 33GB
or 33E9 bytes (30.7GB).

VXA drives can adapt their speed to how fast the host actually
delivers the data.  However, I'm fairly sure that writing slowly
(where other drivers would backhitch) will reduce tape capacity.
Quite possibly dump can't keep up with the native speed of the
drive.

-- 
Christian "naddy" Weisgerber                          naddy_(_at_)_mips_(_dot_)_inka_(_dot_)_de



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