Hi,
Trying to determine the true compression ratio of our
data (advfs) to tape, so used:
vdump 0f - /filesystem|compress -v|wc -c
For one file system, (binary files most of them), it
gave me -23%compression, thus 25GB of data, upon
compression, spitted out 31GB. (I know about how some
other files enlarge when compressed)
Questions:
1. Using device nrmt0h (4.0g, with a tz88 20/40
drive), is it clear that using compression will
actually just take more tapes(dltIV) and time? or does
the algorithm for compress I used with vdump differ
with that of the device file?
2. If #1 is clear/true, then it is also true that
there is no way to fit 40GB of data into this tape
(DLTIV) using this drive.
3. Started a vdump (as above) on a 315GB fs monday,
and now it is 36hrs later and it is still going
80%done, is that normal or is there something I could
have done to speed up the process (4.0G, 2100Alpha,
4CPU's EV5, and, and, mmmhhh!! , 128GB swap too small
huh?...non production machine)
4.I usually dont use vdump. I use plain old tar for
bkups. Would a real bkup to tape of a filesystem,
315GB take this long using vdump?
_Thanks in advance.
Richard
SAIC
Greenbelt, MD
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Received on Wed Aug 01 2001 - 14:04:40 NZST