[mdlug] Quotas. How do they work?

[Mark Montague]

  On March 29, 2011 10:47 , "Robert Adkins II" <radkins at impelind.com> 
wrote:
> The reason for holding these users to a quota is important. If I do not,
> then they will continue to grow their email storage, indefinitely. It is
> literally a teeth pulling operation to "permanently" remove data from the
> servers that is 6 years out of date. So, I'm looking at having to manage
> inboxes with a potential size of "unlimited".

That's the same situation that the University of Michigan is in with 
their main campus-wide IMAP service, actually, and it hasn't caused a 
problem.  There are no quotas, and the potential size of inboxes is 
"unlimited".  Most people don't keep tons of mail, and the rate of 
growth of email storage is entirely manageable.  Keep in mind that while 
most students will leave after 4-5 years (undergraduate) or 7-9 (Ph.D.) 
-- and mailboxes are deleted around 6 months to one year after someone 
departs -- most staff and faculty stick around for longer.

I've included some statistics below that some people may find interesting.

--
   Mark Montague
   mark at catseye.org


------------------------------
  IMAP Usage Summary 2011-03-28
------------------------------

--- total disk data  ---
64.84 TB (73.2%) disk used of 88.63 TB total
There are 14.93 TB left before 90% utilization

--- total size data  ---
61.86 TB total for 85342 users

average:  760.03 MB
median:   302.01 MB

--- user size distribution ---
under 50MB:   21776  25.52%
under 200MB:  35850  42.01%
over 1GB:     18994  22.26%
over 5GB:      1373   1.61%

--- aggregate folder sizes ---
trash:     1259.36 GB  (2.0%)
SpamBox:    102.29 GB  (0.2%)

--- usage statistics ---
active users:    69510 (81.4%) -- read or received mail
logged in users: 52521 (61.5%)
disabled users:   5370 ( 6.3%)

--- client statistics ---
web users:     41195 (78.4%)  web-only users:        0 ( 0.0%)
proxy users:   52521 (100.0%)  proxy-only users:  11325 (21.6%)
gpcc users:        3 ( 0.0%)  gpcc-only users:       1 ( 0.0%)

--- messages delivered ---
10604330 total messages delivered
   127429 messages delivered to SpamBox ( 1.2%)

--- total system load ---
336284.64 total system load
      4.84 active user average load

--- load by process ---
imap: 295236.43    pop:  18896.48    lmtp:  22151.72
            87.8%              5.6%               6.6%

--- total logins ---
imap: 28561295    pop: 7245908
          79.8%           20.2%