John mentioned:

>Additionally, anybody out there using mirrored technology?

One thing to keep in mind with TurboIMAGE logging versus mirroring
(no matter if Mirrored Disk/iX software or hardware RAID-1) that they
do provide different types of protection. Mirroring, for example, is
no rescue if you damage or corrupt your data(base) from the software
side (e.g. accidentally delete or modify data or datasets). You will
simply end up having two identical copies of the result. With Image
logging on the other hand, you could restore your backup database and
re-apply (roll forward) the logfile transactions up to a desired point
in time (e.g. shortly before the damaging activities started).

It's not that logging or mirroring is "better". They're just different.

Oh by the way, two URLs for manual sections that I found useful:

 TurboIMAGE/XL Database Management System Reference Manual
   Ch 7.  Logging and Recovery
     http://docs.hp.com/cgi-bin/doc3k/B3039190010.17091/57
   Ap G. Recovery and Logging Quick Reference
     http://docs.hp.com/cgi-bin/doc3k/B3039190010.17091/122

I also have some screen snippets way back from my MPE/V days that show
a cycle of enabling logging, performig a couple of transactions, then
using DBUTIL ERASE to simulate an accident, and finally using DBRECOV
for a rollforward recovery. It's very very old, but I can dig it up if
you'd find it useful. (kind of a pun... this logging example was created
with log bottom enabled in the terminal emulator ;-)

Lars.

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