Re: SUMMARY: Full Dump - single-User or not?

Date: Fri Mar 26 1993 - 23:51:20 CST

In article <bern.733112438@kleopatra> bern@Uni-Trier.DE (Jochen Bern) writes:
>Hello Netters,
>some Days ago I posted a Question about Level 0 dumps on SUNs; I had read on
>comp.unix.admin that there *are* Reasons to do it single-User, but OTOH Sun
>Manuals showed Level 0 performed in multi-User.
>I received 10 Replies, and here is the Result for the uninterested Readers:
>Use many rotating Tapes, dump multi 2
>single-User / un-/remount Filesystems 3
>there's no Problem unless you're in *BAD* Luck 2
>Use a Backup Software that does Locking 1
>What's so special about Level 0 (vs. Level >0), anyway? 1
>(I. e., nine gave Recommendations, one enumerated the Possibilities and
>their Cons and Pros.)
>To be more detailed: The Problem in Level 0 (as probably most of you will
>know) is that dump expects the Filesystem to be "silent", i. e., it isn't
>able to ward off Changes between the Times it looked up the Inodes and the
>Times where it actually dumps them. The two IMHO most flagrant Results are
>-- File of User A gets replaced by File of User B: restore will create a
> File owned by A but with (Part of) the Data of B --> Security Breach
>-- Directory gets replaced by File: restore expects only Files to come as
> soon as it meets the first File. Thus, all Dirs behind the affected
> dump Record can't be restored as Dirs, so the Files in them can't be
> restored at all. Note that this proves that a Change may trash other
> (unchanged) Inodes!

So, would it be a good idea to do dump 0f /dev/null /dev/rsd0a once and
than just do level 1 dumps rather than level 0?


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