[horde] Memcache server questions

[Michael M Slusarz]

Quoting Steve Devine <sd at msu.edu>:

> Quoting "Kevin Konowalec" <kevin.konowalec at ualberta.ca>:
>
>> Unless I've done something really wrong horde will use a whole whack
>> of servers if you choose - just add all the ip addresses and ports
>> comma-seperated in the config tool (or conf.php).  Is that NOT the
>> case???  I don't believe it is since when once machine goes down all
>> of a sudden x% of the sessions vanish and my phone starts ringing....
>>
>> K
>
> Yes exactyl its failover in the sense that the whole thing (Horde)  
> doesn't crash but all the sessions are lost and everyone is logged  
> out. When they log back in they get the next server in the config.  
> At least thats my thinking please someone correct me if I am wrong. :(

Sounds like you are running into the bug that was fixed via this  
series of patches (these patches are to Horde 3.3):
http://cvs.horde.org/diff.php/framework/SessionHandler/SessionHandler/memcache.php?r1=1.1.2.8&r2=1.1.2.11

These fixes will be a part of Horde 3.3.1.

>>> Ok thanks for your reply. It seems to me however that no matter what
>>> you do you are only going to have one memcache server at a time
>>> servicing the front ends so the load will always fall to one
>>> individual box. You could divide the system up like so
>>> Frontend 1~4 => memcache_server-a
>>> Frontend 5~8 => memcache_server-b
>>> etc
>>> But then your sessions will not survive crossing over from frontend
>>> 1~4 to frontend 5~8.

Note that memcache 3+ (currently marked as beta) adds some additional  
features such as redundancy that might interest you -- see  
http://pecl.php.net/package/memcache/3.0.0 (note that the  
'session_redundancy' option mentioned on that page only applies to the  
memcache session handler, *NOT* the Horde memcache sessionhandler.  
These are 2 entirely different session handlers).

michael

-- 
___________________________________
Michael Slusarz [slusarz at horde.org]