backup strategies

Csaba Henk csaba-ml at
Mon Oct 31 08:10:26 PST 2005

On Mon, Oct 31, 2005 at 09:40:16AM -0600, Eric Schuele wrote:
> How do snapshots work and how do they provide the consistency necessary 
> for a dump?
> SoftUpdates are required on the filesystem.

This sounds beautiful. I am amazed. I knew of softupdates, but they were
always a shady corner of my understanding of BSD.

So live fs dumping is based on the great hackery of softupdates. Fine,
but in this case... shouldn't the man page make a mention of it?

It just says that -L is ignored in case of unmounted/ro mounted fs-s,
or if there is no proper .snap dir. But it doesn't say that it will be
ignored if softupdates is not turned on...

Going a bit off: which OS-es provide this live snapshot dumping
capability? FreeBSD? FreeBSD >= 5.x ? *BSD ? Maybe something else?
(AFAIK, softupdates is supported also in other members of the BSD
family, yet the NetBSD dump manpage didn't have such a -L flag...)

Csaba Henk

My sense of humour is often too subtle to cope with getting smileyd.
Please don't take it personal.

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