[Imap-use] replication

[Jeroen van Aart]

Mark Crispin wrote:
> The first is that, as Joel Reicher points out, NFS doesn't really add 
> any benefit.  It just moves the single point of failure from the IMAP 

> machine.  The problem is that there is NO REASON why an IMAP server 
> machine should be any more likely to crash than the NSFH.

Yes that's what I already figured when I started thinking about 
replication. In the same line of thought, why would a SAN or DAS (or ata 
over ethernet, iscsi) be any less likely to crash than an imap server?

> it finally dawns on you that since IMAP load is primarily I/O load, the 
> NSFH is going to fail to scale for that load just as badly as the ISFH 
> fails.

Which I guess leads to the logical conclusion that distributing email 
accounts over multiple servers is the better solution (that's the uw 
approach if I understood correctly). So if one server fails not everyone 
is affected. The replication idea would, in theory, just make recovering 
from that failure easier, by switching to a live backup holding the same 
mailboxes.

> It saddens me that, after 20 years, I still have to explain the same 
> thing over and over again.  I have little doubt that certain 

I hope you didn't think I needed that explanation, as I already figured 
that.

Best regards,
Jeroen