LARGE single-system Cyrus installs?

[Dale Ghent]

On Oct 4, 2007, at 2:41 PM, Vincent Fox wrote:

> We spent some time talking to Ken & Co. at CMU on the phone
> about what happens in very high loads but haven't come to a
> "fix" for what happened to us.  There may not be one.  I can and
> will describe all the nitty-gritty of that post-mortem in a post in a
> day or two.

One of the things Rob Banz recently did here was to move the data/ 
config/proc directory from a "real" fs to tmpfs. This reduces the  
disk IO from Cyrus process creation/management.

So the way we do stuff here is that each Cyrus backend has its own  
ZFS pool. That zpool is divided up into four file systems:

/ms1/data
/ms1/mail
/ms1/meta
/ms1/sieve

"ms1" in this case is the name of the zpool... named after the server  
which owns it.

Additionally, we have /ms1/data/config/proc mounted as a tmpfs file  
system. The info in that dir does not need to persist across reboots,  
and every time a new Cyrus process is launched, a file (pid number)  
is written there and is updated with state info. This produces  
unnecessary disk IO, so it's better of being a in-memory filesystem,  
which tmpfs is.

The relevant areas of our imapd.conf looks like so:

configdirectory: /ms1/data/config
defaultpartition: ms1
metapartition-ms1: /ms1/meta
partition-ms1: /ms1/mail
sievedir: /ms1/sieve


/dale

--
Dale Ghent
Specialist, Storage and UNIX Systems
UMBC - Office of Information Technology
ECS 201 - x51705