[OpenAFS] user home directory replication

[Todd Lewis]

On 07/14/2010 01:43 PM, Jonathan Nilsson wrote:
> I would like to replicate home directories (and other AFS volumes that
> are primarily accessed read/write) for the purpose of faster disaster
> recovery in certain common cases, such as local hardware failure on an
> AFS File Server.

Others have offered good advice based on their years of experience that 
should be helpful in making this work. By "this" I mean attempting to 
take advantage of volume replication in a disaster recovery strategy as 
a proxy for high availability.

My personal opinion here: Don't do this. At least not until you have 
more experience with "normal" AFS. AFS doesn't provide high 
availability, but you can approach it by using more robust hardware. 
Whether such a disaster recovery scheme is feasible depends largely on 
the hardware resources available to you vs. the number and size of home 
and other volumes you intend to support this way. However, very few 
sites actually do this, which should tell you something...

In general, confusing these three different things -- volume 
replication, disaster recovery, and high availability -- combined with 
insufficient experience is likely to _increase_ your need for the latter 
two. Everything you've posted so far seems to indicate you take your 
system administration seriously, so I've no reason to doubt your 
abilities or the effort you are willing to put into making this work. 
However, AFS was not designed to work this way. I think your efforts 
would be better spent in putting up a "normal" AFS cell and building 
your experience before attempting to bend it this way.

However you eventually decide to go, you have my full support (for what 
that's worth), but I think we (the OpenAFS community) would be remiss 
for not at least showing the other side of this coin.

I'll go away now. Good luck,
--
Todd Lewis <utoddl@email.unc.edu>