[OpenAFS] Re: read-only to read-write fast?

Brandon S. Allbery KF8NH allbery@ece.cmu.edu
Sat, 16 Aug 2003 20:52:55 -0400


On Saturday 16 August 2003 19:23, Hein Roehrig wrote:
> Ah, very good! So it *is* possible to achieve some sort of
> home-directory replication; this is in contrast to
> 
> 
http://grand.central.org/twiki/bin/view/AFSLore/AdminFAQ#3_16_Can_I_replicate_my_user_s_h

You can simulate it, sort of.  The problem is that it's not fast replication 
(since you need to create/restore the volume) and you'll lose anything since 
the last successful backup; for most people this does not constitute *useful* 
replication after the fashion of AFS's replication of R/O volumes, especially 
since people expect their home directories to be available all the time.

(Doing live replication with R/W volumes is a Hard Problem; the Coda project 
was working on it but its replication even of R/O volumes was never 
especially reliable because the support for R/W replication complicated 
things so much.  Which is why nobody recommends Coda for production use.)

> Now the only remaining question is, can I get a rw volume from a ro
> volume without dumping & restoring the ro volume?

I don't think so.  This is why it's not suggested as a workable way to do R/W 
replication.

-- 
brandon s. allbery   [linux,solaris,freebsd,perl]      allbery@kf8nh.com
system administrator      [WAY too many hats]        allbery@ece.cmu.edu
electrical and computer engineering, carnegie mellon univ.         KF8NH
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