SUMMARY: Backup while in multi-user mode

Mike My Watch Has Windows Meyer mwm at pa.dec.com
Wed May 22 02:10:50 AEST 1991


In article <690 at silence.princeton.nj.us> jay at silence.princeton.nj.us (Jay Plett) writes:
   Look at the odds.  The probability of a disk crash on any particular
   day is really very small.  The probability of a bad level 0 done on a
   live filesystem might be larger, but it's still small. The probability
   of two successive bad tapes is smaller.

This last statement is only true if you assume that bad dumps are
unrelated. This is a false assumption. Given that someone was doing
something that caused a dump to be bad one day, I'd say the
probability of them having done that the previous day is larger than
the probability that a dump would be bad.

And the longer they've been doing it, the more likely it is that the
dump is bad. For instance, if you find that every dump made on a
weekday night for the last month is bad, which way would you bet on
the dump for tonight, if it were a weekday?

You're right - a stable file system doesn't guarantee that you can do
a restore. It eliminates one source of problems, and one that can be
set up to occur on a regular basis, at that.

	<mike
--
But I'll survive, no you won't catch me,		Mike Meyer
I'll resist the urge that is tempting me,		mwm at pa.dec.com
I'll avert my eyes, keep you off my knee,		decwrl!mwm
But it feels so good when you talk to me.



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