Hi,

We run a zimbra community server with around 5000 mailboxes. Our temporary machine config (till we get a new one soon) is:
PIV, 3.0 Ghz, 1.5 GB RAM
OS: RHEL 4, 1 GB swap (I had done this when we had lesser RAM)
Other software: Mailman, Zimbra v 3.1 (open source edition)

Though sluggish (webclient only, not server end), this had been running stable since the past 2 months. Now we are facing a few issues. The issues/questions I have are:

1) Antispam seems to be working overtime. Both functionally and in terms of punishing attitude on the hardware.
a) Functionally: This thing sometimes puts even proper mail in the junk mail folder. Whether it comes from yahoo, gmail, hotmail or any private domain... mails are getting into the junk mail folder which should otherwise go to the inbox. How do I get this to work properly?
b) resource hungryness: My swap seems full. RAM fluctuates between 50 MB free to 2 MB free. When it is around 2 MB free, I see a lot of activity on "dspam_clean" process. Please find attached at the end, an output of "top" command. Web clients show a message like "server taking too long to respond... [cancel request button]". How do I optimise the performance to overcome this problem?

2) Mailboxes sometimes show "n" new emails. though there are no new emails. What can I do to let my system show correct figure?

3) I would want to use tomcat, http etc. for our other applications we are going to run on this system (the newer one). We are going to run "Liferay" an open source CMS cum portal server. This brings up a few more questions:
a) Can I configure common components for use with zimbra? Mostly these will be openLDAP, apache, tomcat, MySQL, etc. What would be the implications if at a later date I want to upgrade my zimbra server?
b) To optimise performance, can I use different versions of the above projects customised for my use?
c) To optimise performance, can I disable a few features of COS like calendar, IMAP, etc.? Will this help me salvage a few of the hardware resources?

4) I had tested zimbra on a smaller domain earlier. What I have realised is that the performance drops considerably after 55-60 days uptime. Has anyone else faced a similar issue? We are using zimbra for its integrated features, not necessarily for the collaborative environment or AJAX like system. Can we use open source third party calendar front end and horde/IMP for mail front end to work with zimbra? Please do write if anyone has successfully implemented these.

Lastly, we are developing JSR-128 compliant portlets for use with Liferay portal server. In case we make a decision to use zimbra and if things shape up well... we will try and release this code to everyone. The functionality expected out of this is similar to people seeing their webmail on "My Yahoo" or "Google personalised home page".

Any kind of help on the above four questions, however small, will be really appreciated.

Thanks,
Vivek

#top --> Output
top - 04:14:50 up 63 days, 1:17, 2 users, load average: 15.61, 15.78, 14.61
Tasks: 174 total, 2 running, 172 sleeping, 0 stopped, 0 zombie
Cpu(s): 4.3% us, 1.7% sy, 0.0% ni, 0.0% id, 94.0% wa, 0.0% hi, 0.0% si
Mem: 1522664k total, 1490548k used, 32116k free, 4564k buffers
Swap: 1052248k total, 1049972k used, 2276k free, 145140k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
29347 zimbra 18 0 1288m 1.0g 70m R 4.0 71.6 79:52.67 dspam_clean
11802 zimbra 25 0 736m 153m 1636 S 0.7 10.3 115:21.05 java
16393 postfix 15 0 10856 896 472 S 0.7 0.1 9:12.25 qmgr
28253 postfix 18 0 6844 1296 1196 D 0.3 0.1 0:02.71 showq
11643 postfix 18 0 6852 1568 1232 D 0.3 0.1 0:00.31 showq
1 root 16 0 3592 316 292 S 0.0 0.0 0:04.94 init
2 root 34 19 0 0 0 S 0.0 0.0 0:01.25 ksoftirqd/0
3 root 5 -10 0 0 0 S 0.0 0.0 0:00.35 events/0
4 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 khelper
5 root 15 -10 0 0 0 S 0.0 0.0 0:00.00 kacpid
31 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 kblockd/0
32 root 15 0 0 0 0 S 0.0 0.0 0:00.00 khubd
44 root 7 -10 0 0 0 S 0.0 0.0 0:00.00 aio/0
43 root 15 0 0 0 0 S 0.0 0.0 48:56.44 kswapd0
118 root 15 0 0 0 0 S 0.0 0.0 0:00.00 kseriod
185 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 ata/0
187 root 22 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_0
188 root 23 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_1
200 root 15 0 0 0 0 D 0.0 0.0 16:30.15 kjournald