Hi,
We have about 5% of our DLT7000 tapes frozen. We had the feeling that
more tapes became frozen since we upgraded the microcode of the tapes to
V106, although after some extra manual cleaning - it is not as bad now.
This microcode version reduces the need for cleaning the drives.
I tried unfreezing the frozen tapes, and some of them worked just fine
from then on. I don't have statistics on how many of them.
Duplicates are always VERY slow. I heard that version 4.5 improves the
performance of duplications, and I can't wait...
Multiplexing should take into account the location of the clients. It is
better to put in the same multiplexed class clients that are connected
via different lines, which doesn't always go with the natural tendency
to put in a class clients of the same department.
Miriam
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Miriam Ben-Haim E-mail: miriam AT technion.ac DOT il
Unix Systems Phone : +972-4-8292177
Taub Computer Center Fax : +972-4-8236212
Technion - Israel Institute of Technology, Haifa 32000, ISRAEL
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On Fri, 18 Jan 2002, Brian Horn wrote:
>I know this can vary widely, but about what percent of frozen DLT media
>do you see in your libraries? Or some idea along the lines of: "none",
>"a few", "some", "more than I would have thought". For a long time, we
>were at "a few", but recently we've jumped to "some", and appear to be
>heading toward "more than I would have thought". Along those same
>lines, we are enountering more instances more often of SOME slow backups
>and SOME slow duplications. Most of our backups and duplications run fin.
>The slowness always seem to involve the same tapes, but they DON'T
>actually error/freeze. Just really painfully slow. Any hints on that?
>Backups and duplications are both multiplexed. Based upon previous
>posts here, we did increase the NET_BUFFER_SZ to 262144, and haven't
>seen any detriment, but also haven't seen improvement of our slow
>backups.
>Also, we write Oracle archive log files to tape every couple of hours,
>so these tapes get a lot of mounts. Would this rapidly degrade our tapes
>due to tensioning, etc?
>
>--
>The wisest mind has something yet to learn.
>George Santayana
>----------------------------------------------------------
>Aristotle maintained that women have fewer teeth than men; although he
>was twice married, it never occurred to him to verify this statement by
>examining his wives' mouths.
>Bertrand Russell -- The Impact of Science on Society, 1952.
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