Quoting John Murtari <[email protected]>:
Folks,
My two-bits on this conversation. We'd also been using
Horde for quite a few years and primarily IMP to support web
based email for our customers. Have never been happy with
it's performance on HTML messages, even in the newest version.
Any specific problems you could enumerate? Do understand that we are
much more proactive and thorough with our HTML filtering, so the
trade-off you may be seeing is security vs. performance.
One of the other support guys recommended something
he has been using at home called RoundCube. We quickly had
it up and running as a test install on our servers and folks
love it. Does the 'ajax' magic and really renders the screen
very close to what you would see with Outlook, Thunderbird.
IMP has had this for years. It is called dimp.
I don't mean to rain on the Horde parade! But hopefully
the Horde development folks can look at the way these guys
handle message display and get some ideas.
Responding to the other main post in the thread: any questions on
performance need to be described in a bit more detail. There are
multiple components in an IMP installation that have to be considered:
network bandwidth, IMAP server, disk I/O (server, IMAP server),
database performance, HTTP server performance, PHP performance, etc.
It makes a big difference where the bottleneck lies.
For example, Apache + PHP is, IMHO, no longer a viable solution for
large installations. Way too bloated. Using something like lighttpd
+ FastCGI is much faster and easily scalable, especially if the load
is concentrated in the Apache/PHP process. If, on the other hand,
load on the database is the limiting factor (it is unclear from the
message whether it was or not), that presents a different set of
questions. Are you using split read/write DB's? IMP itself is not a
heavy database user in and of itself (IMP's major data source is the
IMAP server), but other choices may increase that load. For example,
more recent version of IMP use caching, which wasn't present on older
versions. However, misconfiguring the cache could potentially result
in increased load/decreased performance.
For example, Horde caching should probably not be used on databases.
The guaranteed persistence of DB storage (and its concurrent increased
performance demand) is precisely *not* what is needed/desired for
caching. You will most likely saturate the DB and there is absolutely
no reason this should happen. Instead, caching should be tailored on
the architecture of the server farm. Using Apache + PHP with
persistent connections from the frontend? It will most likely be
fastest to simply use local file caching (although you do run the risk
of causing duplicate cache data across multiple backend servers if the
frontend load balancer does no always point a user to the same backend
server). Better yet, memcached is the perfect solution for Horde-type
caching. At this point I can say that if you are a large installation
and are not using memcache (or a similar solution) for caching, you
are probably doing caching wrong (ask Facebook - without memcache, it
would not be able to run period.)
A more likely scenario is bottleneck on your IMAP server. This can be
caused by various things such as the way your store messages on the
storage backend to the speed of your disk drives. Using a server that
caches data can help speeds. but the one place that admittedly is a
potential slow spot in IMP 4 is the use of c-client (the PHP imap
module) to access the IMAP server. For various reasons that would
take me many pages to explain, c-client is horrendously inefficient in
IMAP communication and lacks certain features that used to cause us to
have to send a bunch of additional IMAP commands to do what we want.
However, this problem has been solved. The IMAP client has been
rewritten to use a brand new PHP-based client in IMP 5. I don't have
true benchmark numbers, but I can tell you that in unofficial results
on a large mailbox on the same server with a heavily loaded IMAP
server, initial mailbox access took 10 seconds in the IMP 4 client and
2 seconds in the IMP 5 client. So I am claiming 500% performance
improvement :)
michael
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Michael Slusarz [[email protected]]
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