upgrading a 2.2.12 murder to 2.3.14

[Gavin Gray]

We are planning towards upgrading our existing murder. The murder has  
four front ends, three backends and separate mupdate and lmtp servers.  
We want to move from version 2.2.12 to 2.3.14 so that we can make use  
of delayed expunge an possible replication.

We have several thousand users currently having 4 TB of mail.

Any comments on the following would be welcome:

1. We plan to gradually migrate users from the existing backend  
machines to new backend servers running 2.3.14 that have been  
integrated into our murder. We plan to do this using xfer. Although  
this is very time consuming we are under the impression that cyrus  
recommends using imap itself to do migrations rather than trying   
underlying filesystem copies of some kind.

2. We should end up then with our existing murder but with three  
backends running 2.3.14. We then plan to upgrade the other machines in  
the murder to 2.3.14 in the following order: frontends then lmtp and  
finally the mupdate server. Does this make sense?

3. As part of our preparation for this work we have been experimenting  
with cyrus replication. The replication protocol seems pretty solid,  
however we have some concerns about how to make use of it in our  
upgrade. We are considering having a replicant machine for each of the  
new backends. But this makes the migration even slower. In our tests,  
if we migrate users via xfer to a machine that is doing rolling  
replication, the replication takes around three times as long to  
complete as the xfer. Does anyone have any experience of migrating to  
a replicating environment?

many thanks,


Gavin Gray


-- 
Gavin Gray
Edinburgh University Information Services
Rm 2013 JCMB
Kings Buildings
Edinburgh
EH9 3JZ
UK
tel +44 (0)131 650 5987
email gavin.gray at ed.ac.uk

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The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.