Quick advise regarding Cyrus migration

Bron Gondwana brong at fastmail.fm
Sat Jul 23 09:46:17 EDT 2016

Skiplist should be clean for a 32 bit to 64 bit architecture change.  It's all very type-careful internally.  It's also endian-change safe, because it uses network-byte-order for everything internally.

We definitely did a 32 bit to 64 bit conversion (probably slightly earlier - Debian 6 to 7) at FastMail, and we didn't have any problems.



On Sat, Jul 23, 2016, at 20:18, Roman Medina-Heigl Hernandez via Info-cyrus wrote:
> Hi guys,
> I'm running Cyrus Imap 2.4.16 on Debian 7 (x86) 32 bits and I need to
> migrate to 2.4.17(nocaldav) on Debian 8 (x86) ** 64 bits **.
> I've been reading some articles (like this one, which is 6 years old: 
> https://cynici.wordpress.com/2010/12/06/how-to-migrate-32-bit-cyrus-imapd-mailboxes-to-64-bit/
> ).
> My question is: is it really needed to convert .db from skiplist to
> flag, and then back to skiplist , as suggested by many articles? (or
> even rebuild mailboxes like in last pointed article). Both machines are
> x86, being the only difference 32 vs 64 bits (endianness is same, etc).
> I did a quick test simulating the migration, by simply just copying
> /var/lib/imap, /var/spool/mail and /var/spool/sieve. It seems it worked
> fine (or at least I couldn't find any problem when running imap with the
> migrated data). But I'd need your confirmation this should be sufficient
> and I won't find problems in the future.
> I also played with db conversions (skiplist -> flat -> skiplist) and I
> have some questions:
> - I converted annotations.db (skiplist) to flat and then back to
> skiplist. It passed from 11K to 144 bytes (both skiplist)!!! Is it normal?
> - I did same exercise obtaining new skiplist db in both machines from a
> same flat. I got a vey similar (but not exactly the same) result .db in
> both 32 & 64 bits (some minor bytes may change but it didn't seem like
> big differences/changes). Maybe some different metadata (I mean not
> important), or I should concern about it?
> - apart from .db's from /var/lib/imap, should I worry about other
> skiplist like .seen files in /var/spool/mail?
> Sorry if there are too much questions but this migration is important, I
> cannot loose any data (email data + email metadata: read marks, etc).
> Please, advise!
> Thank you so much in advance and have a nice day!
> -- 
> Saludos,
> -Román
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  Bron Gondwana
  brong at fastmail.fm

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