A Darren Dunham wrote:
On Fri, Feb 26, 2010 at 06:05:50PM -0500, George Sinclair wrote:
Why does scanner have to recover the data to standard output just to
rebuild the media database (-m) entry? This makes no immediate
sense.
If I have a tape with, say, 10 GB total, and I run scanner as:
scanner -s server device
and it finishes generating a table of contents in one minute or so,
Can you show me the "table of contents" output?
It turns out that I was not redirecting the output to /dev/null.
Instead, it was just going to the console. Clearly, if you're not
interested in doing a raw recover (usam) - and I wasn't - then it's a
waste of time not to redirect it, so I reran it
as:
scanner -s server -f mediafile -r mediarec -S ssid /dev/nst0 > /dev/null
and this time it ran lickity split!
It did, however, identify the tape as an LTO-4, and it's actually an
LTO-3, but it recorded the saveset now as being on an LTO-4. I'm
thinking that I might need to remove the save set from the media
database and rescan it, including the '-t Ultrium LTO-3' option this time?
why can't NW do the same thing when using the '-m' option to rebuild
the media index? Why does it have to read the data to do that?
The media database includes the location of every fragment of the SSID.
What option is that in mminfo? Can I query on that?
Scanner cannot report on it without reading it. There's no way to
generate that information just from reading the beginning of the tape.
1. So, lets say that you're scanning a 100 GB save set, and you're not
rebuilding the client file index entries (-i), just the media data base
entry (-m). Under normal circumstances if it took you 1.5 hours to back
up/recover that amount of data then can you expect it to possibly take
that long to scan in the save set, accounting, of course, for the fact
that you're not sending anything over the network? Is it reasonable to
assume that the scan would be no slower than backing it up?
2. If you're using '-f mediafile -r mediarec' options then it should be
reasonably quick to get it at least to the start of the save set, correct?
3. What about when you're rebuilding the client file index entries (-i)?
How much more time does that generally add?
George
I can
see that maybe when using '-i'. What more information does it need
to rebuild the media database entries than what you get back from
the table of contents?
--
George Sinclair
Voice: (301) 713-3284 x210
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