[Dovecot] keep users from deleting email

[Bill Cole]

At 10:28 AM -0500 4/14/08, Adam Williams  imposed structure on a 
stream of electrons, yielding:
>Bill Cole wrote:
>>
>>Um, really?
>>
>>I've had a little experience with SOx, HIPAA, GLBA, and Federal 
>>E-Discovery compliance projects, and I've never heard that SOx 
>>applied at all to state agencies or that it requires anyone to 
>>archive all email forever. In fact, doing so as a matter of normal 
>>policy may be a very bad idea under the E-Discovery rules. I'm 
>>certainly no lawyer, but your management may want to find better 
>>ones than they seem to have...
>>
>Well it doesn't, but management wants us to archive all electronic 
>data forever in a fashion that is compliant to that law.
>>
>>You definitely need to be aware of the fact that one of the 
>>downsides of mbox is performance and resource demands as the mbox 
>>files grow.
>What do you consider a large mbox?  We have users with single mbox 
>files of 3G and their mail loads up fine.  We are using Seamonkey's 
>email client and it makes a local index file of all the message 
>to/from/subject/date/etc so it loads mail very quickly, pretty much 
>instantaneous.  One thing I don't like about Maildir is that it 
>keeps each message as a seperate file, so you'll end up with 
>directories with 20k+ files and run into glob problems, and with 
>ext3, you have all these sub 4kb messages still taking up a 4k block 
>on the disk, wasting disk space.

Well, I suppose that if you never delete any messages you avoid the 
worst mbox performance problems, since you never need to re-write the 
whole file. Between Dovecot's indexing and client-side indexing, 
mboxes that only ever get written to by adding more messages might 
not be such a big deal.

The interesting issue would then be the size of the Dovecot index 
files. I don't know if they are designed to work well when all of 
your users have tens of thousands of messages in their index. I 
expect you'll want a lot of RAM...
-- 
Bill Cole                                  
bill at scconsult.com