Hello,

in the last week I have problems with slowness, pop and imap client receive timeout while webmail is very slow to respond.

I accurate that are not bandwidth problems.

The server has a very low load.

I have not found any messages that might indicate problems in the last week.

Except one out of memory:

Code:
2013-11-04 16:17:47,980 FATAL [LmtpServer-29] [ip=192.168.1.1;] system - out of memory
java.lang.OutOfMemoryError: Java heap space
        at com.zimbra.common.util.BufferStream.buffer(BufferStream.java:72)
        at com.zimbra.common.util.BufferStream.write(BufferStream.java:383)
        at com.zimbra.common.util.CopyInputStream.read(CopyInputStream.java:73)
        at java.io.FilterInputStream.read(FilterInputStream.java:133)
        at com.zimbra.common.mime.Rfc822ValidationInputStream.read(Rfc822ValidationInputStream.java:53)
        at com.zimbra.common.mime.Rfc822ValidationInputStream.read(Rfc822ValidationInputStream.java:75)
        at com.zimbra.cs.store.BlobBuilder.append(BlobBuilder.java:133)
        at com.zimbra.cs.store.file.FileBlobStore.storeIncoming(FileBlobStore.java:101)
        at com.zimbra.cs.store.StoreManager.storeIncoming(StoreManager.java:143)
        at com.zimbra.cs.lmtpserver.ZimbraLmtpBackend.deliver(ZimbraLmtpBackend.java:346)
        at com.zimbra.cs.lmtpserver.LmtpHandler.processMessageData(LmtpHandler.java:376)
        at com.zimbra.cs.lmtpserver.TcpLmtpHandler.continueDATA(TcpLmtpHandler.java:73)
        at com.zimbra.cs.lmtpserver.LmtpHandler.doDATA(LmtpHandler.java:365)
        at com.zimbra.cs.lmtpserver.LmtpHandler.processCommand(LmtpHandler.java:181)
        at com.zimbra.cs.lmtpserver.TcpLmtpHandler.processCommand(TcpLmtpHandler.java:66)
        at com.zimbra.cs.server.ProtocolHandler.processConnection(ProtocolHandler.java:188)
        at com.zimbra.cs.server.ProtocolHandler.run(ProtocolHandler.java:127)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:722)
For at least two months aggiungimo users / domains etc.

What tests can I do? For months we have been working without any problems.

environment where the vm resides:

OS:Centos 6.4
Hypervisor: XenServer 6.2
CPU: 4 Intel Xeon E5620 @2.40GHz
RAM: 6GB
SWAP: 2GB
Hyppervisor Storage: running on EMC SAN AX4-5i, 15k SAS disk.
Zimbra: Release 8.0.4_GA_5737.RHEL6_64_20130524120036 RHEL6_64 FOSS edition.
Zimbra Domain: 100
Zimbra User: 494
Zimbra COS: 7
Zimbra Alias: 286
Zimbra Mailing List: 114

Thanks

Alessandro