Very Computer

Hi,

On my server in Solaris 2.6, I have a Sun DDS-3 tape drive (HP C1537A).

When I'm dumping my systems files, I usually save between 12G-14G
(ufsdump
with the default parameters).
It doesn't seems to be the best I can expect with this tape drive (given
for 12G-24G).
The systems files are "classic" (user's files, system, software, ...),
not full of
compressed files.
I heart that the blocking factor has no longer an effect with the
ufsdump, but I didn't
find any confirmation of it.

Is anybody got some urls or information about the ideal parameters for
this
tape drive/ufsdump ?

Thanks,
Philippe.

Quote:> Hi,

> On my server in Solaris 2.6, I have a Sun DDS-3 tape drive (HP C1537A).

> When I'm dumping my systems files, I usually save between 12G-14G
> (ufsdump
> with the default parameters).
> It doesn't seems to be the best I can expect with this tape drive (given
> for 12G-24G).
> The systems files are "classic" (user's files, system, software, ...),
> not full of
> compressed files.
> I heart that the blocking factor has no longer an effect with the
> ufsdump, but I didn't
> find any confirmation of it.

The software-level blocking factor for DAT drives is not a major factor
these
days - the drives do the real blocking themselves, internally, using an
adaptive algorithm.

There are two settings that will make a huge difference...

First, the drive's internal
blocking-factor, set using options in /kernel/drv/st.conf (try "man st") -
DDS-3
drives can handle very large block sizes (over 1Mb).

Then there is the "software" blocking factor (actually the read/write sizes
used
by ufsdump/ufsrestore). These should be set to match the drive's internal
setting.

If you need help figuring out what to do to with st.conf, email me at