We have been running an ADSM server with 8MM tapes for quite awhile, but
we were having quite a few problems with write errors.. So, we decided to
use 4MM tapes when designing our new server. uhhh... whoops.
Out of 75 tapes in the library, over 1/2 of the tapes are now read/only, and
what is worse, reclaims are failing with read errors. I now fear that most
of our backups (and also archives) are junk. I can't trust anything on
tape at all.
Most of the tapes I have had to make 'unavailable' since the reclaims
fail almost all the time, but keep asking for the same tapes over and over
again.
We are running 3 7206-005's and I have had one drive replaced. We have
used three different lots of HP 4MM 120M tapes, Maxell, and IBM. 2 out of
the 8 Maxell tapes we have use have failed with data loss.
At this point, I would estimate that we have lost over 50GB of backup/archive
data. There has been NO data loss with the 8MM tapes, but plenty of
write errors.
Here is some of what were getting from almost all of our reclaims:
ANR9999D pvrgts.c(3504): Invalid block header read from
volume 4MM060. (magic=8285, ver=1, blk=40708 <40754>,
db=32752 <32768,32768,0>)
10/12/1995 01:26:13 ANR1083W Space reclamation terminated for volume 4MM060 -
excessive read errors encountered
Here are the stats on this particular tape:
adsm> q v 4mm060 f=d
Volume Name: 4MM060
Storage Pool Name: 4MMPOOL
Device Class Name: 4MMTAPE
Estimated Capacity (MB): 5,673.5
%Util: 30.4
Volume Status: Full
Access: Unavailable
Pct. Reclaimable Space: 69.6
Scratch Volume?: No
In Error State?: No
Number of Writable Sides: 1
Number of Times Mounted: 100
Write Pass Number: 1
Approx. Date Last Written: 10/05/1995 05:43:47
Approx. Date Last Read: 10/12/1995 01:29:15
Number of Write Errors: 0
Number of Read Errors: 78
Has anyone encountered this with IBM drives or 4MM tapes?
Help would be great!
Bob Booth - University of Illinois
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