[imp] New IMAP server, troubleshooting slow IMP performance

[Simon Wilson]

>>> Hi Simon,
>>>
>>> On Wed, Jul 26, 2017 at 12:07:26PM +1000, Simon Wilson wrote:
>>>> I've just moved over to a new IMAP server on my local network,  
>>>> migrating IMAP
>>>> from a CentOS 5 to a CentOS 7 server in the process. Horde/apache are on a
>>>> separate server on the same network as both the old and new IMAP servers.
>>>>
>>>> I'm trying to troubleshoot laggy performance in Imp since the move.
>>>>
>>>> For example, refreshing the mail list in Inbox and deleting an email each
>>>> take 3 to 4 seconds before the Refresh circle stops spinning and  
>>>> the list is
>>>> updated. This is longer than it was before (1 to 2 seconds typically). It
>>>> just means that overall Imp feels very slow.
>>>
>>> Just a few ideas:
>>>
>>> - Is your imap server respongding slow if you connect with another mail
>>> client, for example Thunderbird?
>>
>> No - feels very snappy from Mailbird.
>>
>>> - Are other php scripts on your webserver where imp is running also
>>> reacting slow?
>>
>> No. WordPress, which is hosted on the same server as Horde, is  
>> performing as normal. I also have a custom PHP app running on that  
>> box, and it's lightning fast. The Horde server is not highly  
>> loaded, CPU usage avg < 5%.
>>
>>> - Are the cache settings for horde and imp the same as they were in the
>>> old setup?
>>
>> I've not changed anything on the Horde server except pointing Imp  
>> and Ingo backends.local.php to the new IMAP server address. I also  
>> rebooted it.
>>
>>> - Are the network settings, especialy routing and DNS, on the new
>>> webserver really OK?
>>
>> The web server has not changed at all, Horde and httpd are  
>> unchanged (apart from the changed config to point to the new IMAP  
>> server), only IMAP has moved. The server IMAP has moved to is  
>> running well - again very low CPU, 4GB RAM. It runs postfix,  
>> cyrus-imapd, associated mail filters, and nothing else. It's not a  
>> high traffic mail server.
>>
>> It's only Imp that appears sluggish when pointing at the new IMAP  
>> server, yet the transactions appear to be fast from the IMAP IMP  
>> debug log. Maybe I'm imagining it... but my seat of the pants dyno  
>> tells me it's slower... :)
>
> Did you try emptying the IMAP cache, assuming you have it enabled?
>

Jan - IMAP cache... the caching I had setup was:

$servers['imap']['cache'] = sql;

I just switched it to nosql to use the mongo nosql setup on the server  
that is used for Horde cache - and the email times have dropped to  
about 0.5s.

Thanks Jan, that was the ticket. I think nosql is probably better  
performance anyway?

Simon.

-- 
Simon Wilson
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