Multi-machine mirroring choices

[Kris Kennaway]

Jeremy Chadwick wrote:

> Compared to UFS2 snapshots (e.g. dump -L or mksnap_ffs), ZFS snapshots
> are fantastic.  The two main positives for me were:
> 
> 1) ZFS snapshots take significantly less time to create; I'm talking
> seconds or minutes vs. 30-45 minutes.  I also remember receiving mail
> from someone (on -hackers?  I can't remember -- let me know and I can
> dig through my mail archives for the specific mail/details) stating
> something along the lines of "over time, yes, UFS2 snapshots take
> longer and longer, it's a known design problem".
> 
> 2) ZFS snapshots, when created, do not cause the system to more or less
> deadlock until the snapshot is generated; you can continue to use the
> system during the time the snapshot is being generated.  While with
> UFS2, dump -L and mksnap_ffs will surely disappoint you.

"a known design problem" in the sense of "intentional", yes.  They were 
written to support bg fsck, not as a lightweight filesystem feature for 
general use.

Kris