[horde] Horde performance with ActiveSync?

[Sebastian Arcus]

On 10/04/18 18:05, Michael J Rubinsky wrote:
> 
> Quoting Sebastian Arcus <s.arcus at open-t.co.uk>:
> 
>> On 10/04/18 15:41, Arjen de Korte wrote:
>>> Citeren Sebastian Arcus <s.arcus at open-t.co.uk>:
>>>
>>>> I have a Horde 5.2.17 + PHP 5.6.35 + Postgresql 9.2 + Lighttpd 
>>>> 1.4.49 with 10 iPhones/iPads in ActiveSync/Exchange mode. The users 
>>>> have fairly large Inboxes - some of them of 20 000+ emails. On IMAP 
>>>> that is not causing any issues, and hardly any load on the server.
>>>
>>> Which IMAP server do you use? Is it local to the webserver?
>>
>> Thank you for replying. I use Dovecot which runs on the same server as 
>> Horde.
> 
> 
> Assuming the load you are seeing is still present after the devices' 
> initial sync, 

Come to think of it, because after the initial setup all devices have to 
re-download all headers, there is a good possibility that 2-3 of them 
are still in the process of pulling down all their headers (one of them 
has 80 000 just in the Inbox). I take it downloading headers can be 
expected to generate a significant load? On imap/Dovecot, the load was 
always negligible, but I suppose ActiveSync+PHP/Horde is a completely 
different kind of beast.

I am happy to let the initial sync finish on all devices, and then see 
what kind of load is still present on the server.

that kind of load makes me think there might be some sync
> loop going on. Are the devices acting as expected? It might help to 
> enable the activesync logging to see what is going on with the devices. 
> Just actively listening for changes should be minimal load. Even with 
> lots of mail being pushed and/or server intensive activities, like 
> searching all email boxes only rarely bumps cpu usage over 10% for me. 
> Like Arjen suggested though, make sure you have things like 
> MODSEQ/QRSYNC enabled on your IMAP server. If you are using a default 
> dovecot install, you probably already do, but it might be worth checking 
> just in case.

Dovecot is 2.2.33 which I compiled myself with default options. There is 
also nothing unusual in the config file - definitely nothing mentioning 
QRSYNC or MODSEQ. I can't seem to find any other way to double-check 
these things are enabled - online searches seem to suggest they are 
inbuilt capability since Dovecot 1.2 or so?

> 
> Also, some older iOS versions (thinking around iOS 7 or so if IIRC) had 
> some major issues with ActiveSync, this is going back quite a while, but
> thought I'd mention it just in case.

Thank you. All devices are iOS 10+ - so this should probably not be the 
case.