Questions before upgrading vom 2.3 to 2.4

[Sebastian Hagedorn]

Hi Pascal,

thanks for your reply! I decided to ask my more specific questions in 
separate mails, but I have a few follow-up questions for you.

--On 5. Januar 2012 19:50:28 +0100 Pascal Gienger 
<pascal.gienger at uni-konstanz.de> wrote:

> In principle it is simple, but I hit a hard ground today. I did the
> mistake to miscalculate the "converting indexes"....
>
> Our storage was perfectly sized to handle the needed IOPS for cyrus
> operation, but having 8000 index files being rebuild simultaneosuly...

I am very aware of that issue, but we haven't yet decided how to handle it. 
I'm actually considering a scheduled downtime for the conversion. I'm 
planning on performing the actual upgrade on a backup of our mail store to 
have an estimate of how long it's going to take.

> Important:
>
> Set lmtp_mail_timeout (when you use postfix to deliver mail) to a low
> value, like 2seconds, because also cyrus lmtpd triggers the index
> rebuild of a INBOX. So people with less mail in their INBOX (which
> already constructed index and cache) still get their mail in their
> INBOX, and people having MANY mails so that the index rebuild takes time
> will get the mail later due to the early deferred state (after
> lmtp_mail_timeout). Otherwise you'll have many blocked Postfix lmtp and
> no mail gets transferred.

That's a Postfix option, I suppose? We use Sendmail. I don't think there's 
an exact equivalent for that option. Do you know after which LMTP command 
the rebuild takes place? I would assume that it's after "rcpt to:"? So the 
LMTP session has to wait for that before it can issue the "data" command? 
In that case I suppose I could use 'confTO_RCPT'.

> And be familiar with
>
> expunge_mode:
> delete_mode:
> expunge_days:
>
> and the consequences on cyr_expire!

You mean that with "delayed" mode there's a lot to do for cyr_expire? But 
that hasn't changed between 2.3. and 2.4, right? I asked about expunge_days 
in a separate message.

> With meta-partition on a fast SSD device this even would not have
> occured (500 GB SSD needed in our case....)

We don't have any of those, unfortunately ...

Sebastian
-- 
     .:.Sebastian Hagedorn - RZKR-R1 (Gebäude 52), Zimmer 18.:.
                 .:.Regionales Rechenzentrum (RRZK).:.
.:.Universität zu Köln / Cologne University - ✆ +49-221-478-5587.:.
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