Zimbra nginx process defuncting 3000 times per second

Hi everybody,

i'm new to the forum and to zimbra, please be kind to my errors.

I've installed the debian 32 bits opensource edition of zimbra 5.0.6 on a 32 bits updated Debian etch, on a 64 bits server.
With only 5 mail users and only some 20 mails a day, my load average is strange : 2.6.
So i went to see top : it seems nginx is birthed and defuncted 3000 times a second.
I've got a 9.4GB /opt/zimbra/log/nginx.log file, with something like 10000 lines added each second.
Looking on google, the zimbra forum and bugzilla, with the errors from nginx.log, i couldn't find a similar problem (but well, as i said, i'm a newbie with zimbra).
So i wonder if you could point me to my (i hope) obvious failure :-)

Here is the version, load, top, nginx.log and zimbra config :

$ zmcontrol -v
Release 5.0.6_GA_2313.DEBIAN4.0 DEBIAN4.0 FOSS edition

$ cat /proc/version
Linux version 2.6.18-6-686 (Debian 2.6.18.dfsg.1-18etch5) (dannf@debian.org) (gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)) #1 SMP Sat May 24 10:24:42 UTC 2008

$ uptime
17:34:28 up 2 days, 5:29, 1 user, load average: 2.60, 2.77, 2.72

$ top -u zimbra
top - 17:36:35 up 2 days, 5:32, 1 user, load average: 3.06, 2.86, 2.75
Tasks: 110 total, 5 running, 103 sleeping, 0 stopped, 2 zombie
Cpu(s): 5.3%us, 43.9%sy, 0.0%ni, 49.0%id, 1.8%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1027012k total, 1007568k used, 19444k free, 2464k buffers
Swap: 2650684k total, 64k used, 2650620k free, 321680k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15074 zimbra 25 0 4424 836 408 R 27 0.1 21:29.70 nginx
26566 zimbra 15 0 2232 1164 856 R 0 0.1 0:00.02 top
21324 zimbra 19 0 194m 31m 5148 S 0 3.1 0:43.63 slapd
23894 zimbra 25 0 3072 1540 960 S 0 0.1 0:00.00 mysqld_safe
23940 zimbra 15 0 338m 51m 6740 S 0 5.2 0:25.40 mysqld
24191 zimbra 25 0 3072 1536 960 S 0 0.1 0:00.00 mysqld_safe
24230 zimbra 18 0 99548 16m 6028 S 0 1.6 0:23.55 mysqld
30202 zimbra 18 0 56756 47m 2176 S 0 4.7 0:00.91 amavisd
32659 zimbra 16 0 59328 50m 3384 S 0 5.0 0:01.26 amavisd
32663 zimbra 16 0 58488 49m 3380 S 0 4.9 0:01.37 amavisd
32666 zimbra 17 0 58432 49m 3344 S 0 4.9 0:00.74 amavisd
32673 zimbra 16 0 59356 50m 3384 S 0 5.0 0:01.19 amavisd
32678 zimbra 15 0 58856 50m 3352 S 0 5.0 0:01.78 amavisd
32681 zimbra 16 0 60056 51m 3340 S 0 5.1 0:00.69 amavisd
32685 zimbra 16 0 58444 49m 3376 S 0 4.9 0:01.69 amavisd
32688 zimbra 16 0 60652 51m 3356 S 0 5.2 0:01.55 amavisd
32691 zimbra 15 0 61248 52m 3340 S 0 5.2 0:01.01 amavisd
32694 zimbra 16 0 58764 49m 3396 S 0 5.0 0:01.38 amavisd
954 zimbra 17 0 89412 77m 964 S 0 7.7 0:04.78 clamd
1826 zimbra 18 0 11992 6708 2316 R 0 0.7 0:00.03 httpd
1830 zimbra 25 0 11992 6076 1676 S 0 0.6 0:00.00 httpd
1832 zimbra 25 0 11992 6076 1676 S 0 0.6 0:00.00 httpd
1833 zimbra 25 0 11992 6076 1676 S 0 0.6 0:00.00 httpd
1834 zimbra 25 0 11992 6076 1676 S 0 0.6 0:00.00 httpd
1835 zimbra 25 0 11992 6076 1676 S 0 0.6 0:00.00 httpd
10871 zimbra 15 0 6788 2888 2212 S 0 0.3 0:00.40 saslauthd
12509 zimbra 15 0 6788 2872 2196 S 0 0.3 0:00.29 saslauthd
12510 zimbra 15 0 6788 2872 2196 S 0 0.3 0:00.40 saslauthd
12511 zimbra 19 0 6788 2872 2196 S 0 0.3 0:00.42 saslauthd
12514 zimbra 15 0 6788 2872 2196 S 0 0.3 0:00.31 saslauthd
13541 zimbra 18 0 4900 3464 1520 S 0 0.3 0:42.30 zmstat-proc
13545 zimbra 18 0 4772 3292 1520 S 0 0.3 0:00.05 zmstat-cpu
13549 zimbra 18 0 4772 3288 1516 S 0 0.3 0:00.05 zmstat-vm
13551 zimbra 18 0 4776 3300 1524 S 0 0.3 0:00.06 zmstat-io
13557 zimbra 18 0 4768 3288 1516 S 0 0.3 0:00.07 zmstat-io
13605 zimbra 18 0 4636 3232 1516 S 0 0.3 0:00.05 zmstat-fd
13617 zimbra 18 0 4772 3352 1516 S 0 0.3 0:07.86 zmstat-mysql
13619 zimbra 18 0 4636 3240 1516 S 0 0.3 0:00.66 zmstat-mtaqueue
21913 zimbra 18 0 1588 604 508 S 0 0.1 0:00.01 iostat
21927 zimbra 18 0 1712 568 468 S 0 0.1 0:00.00 vmstat
21930 zimbra 18 0 1584 612 512 S 0 0.1 0:00.00 iostat
26255 zimbra 24 0 5532 3940 1552 S 0 0.4 0:00.06 logswatch
26298 zimbra 24 0 5532 3948 1552 S 0 0.4 0:00.06 swatch
26443 zimbra 15 0 8232 6536 1600 S 0 0.6 0:00.14 perl
26464 zimbra 15 0 8212 6508 1600 S 0 0.6 0:00.14 perl
26954 zimbra 19 0 6800 4856 1144 S 0 0.5 0:37.86 zmmtaconfig
27734 zimbra 16 0 8344 4580 2284 S 0 0.4 0:01.04 zmlogger
21021 zimbra 25 0 709m 219m 38m S 0 21.9 0:17.42 java
14664 zimbra 15 0 12480 804 392 S 0 0.1 0:00.00 memcached
23918 zimbra 17 0 3748 1140 908 S 0 0.1 0:00.00 su
24090 zimbra 15 0 4496 1976 1340 S 0 0.2 0:00.01 bash
6275 zimbra 25 0 0 0 0 Z 0 0.0 0:00.00 nginx <defunct>
6276 zimbra 25 0 0 0 0 Z 0 0.0 0:00.00 nginx <defunct>

$tail -f /opt/zimbra/log/nginx.log > /tmp/ng.log
2008/06/13 17:40:34 [alert] 11422#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11422#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11422
2008/06/13 17:40:34 [alert] 11423#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11423#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11423
2008/06/13 17:40:34 [alert] 11424#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11424#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11424
2008/06/13 17:40:34 [alert] 11425#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11425#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11425
2008/06/13 17:40:34 [notice] 15074#0: signal 29 (SIGIO) received
2008/06/13 17:40:34 [notice] 15074#0: signal 17 (SIGCHLD) received
2008/06/13 17:40:34 [alert] 15074#0: worker process 11422 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11423 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11424 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11425 exited on signal 11
2008/06/13 17:40:34 [alert] 11426#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11426#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11426
2008/06/13 17:40:34 [alert] 11427#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11427#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11427
2008/06/13 17:40:34 [alert] 11428#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11428#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11428
2008/06/13 17:40:34 [alert] 11429#0: socket() failed (97: Address family not supported by protocol)
2008/06/13 17:40:34 [error] 11429#0: cannot connect to memcached server 127.0.1.1:11211 (rc:-1)
2008/06/13 17:40:34 [notice] 15074#0: start worker process 11429
2008/06/13 17:40:34 [notice] 15074#0: signal 29 (SIGIO) received
2008/06/13 17:40:34 [notice] 15074#0: signal 17 (SIGCHLD) received
2008/06/13 17:40:34 [alert] 15074#0: worker process 11426 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11427 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11428 exited on signal 11
2008/06/13 17:40:34 [alert] 15074#0: worker process 11429 exited on signal 11

David Pradier

Here is the config :

$ zmprov gacf
cn: config
objectClass: organizationalRole
objectClass: zimbraGlobalConfig
zimbraAccountExtraObjectClass: amavisAccount
zimbraAdminPort: 7071
zimbraAdminURL: /zimbraAdmin
zimbraAttachmentsBlocked: FALSE
zimbraAttachmentsIndexedTextLimit: 1048576
zimbraAttachmentsScanClass: com.zimbra.cs.scan.ClamScanner
zimbraAttachmentsScanEnabled: FALSE
zimbraAttachmentsViewInHtmlOnly: FALSE
zimbraAuthTokenKey: XXX
zimbraAutoSubmittedNullReturnPath: TRUE
zimbraBackupAutoGroupedInterval: 1d
zimbraBackupAutoGroupedNumGroups: 7
zimbraBackupAutoGroupedThrottled: FALSE
zimbraBackupMode: Standard
zimbraBackupReportEmailSubjectPrefix: ZCS Backup Report
zimbraBackupTarget: /opt/zimbra/backup
zimbraCalendarCalDavDisableScheduling: FALSE
zimbraCalendarCompatibilityMode: standard
zimbraCertAuthorityCertSelfSigned: XXX
zimbraCertAuthorityKeySelfSigned: XXX
zimbraClusterType: none
zimbraDefaultDomainName: emma.enc
zimbraFileUploadMaxSize: 10485760
zimbraFreebusyExchangeCachedInterval: 60d
zimbraFreebusyExchangeCachedIntervalStart: 7d
zimbraGalAutoCompleteLdapFilter: externalLdapAutoComplete
zimbraGalInternalSearchBase: DOMAIN
zimbraGalLdapAttrMap: co=workCountry
zimbraGalLdapAttrMap: company=company
zimbraGalLdapAttrMap: description=notes
zimbraGalLdapAttrMap: displayName,cn=fullName
zimbraGalLdapAttrMap: givenName,gn=firstName
zimbraGalLdapAttrMap: initials=initials
zimbraGalLdapAttrMap: l=workCity
zimbraGalLdapAttrMap: objectClass=objectClass
zimbraGalLdapAttrMap: ou=department
zimbraGalLdapAttrMap: physicalDeliveryOfficeName=office
zimbraGalLdapAttrMap: postalCode=workPostalCode
zimbraGalLdapAttrMap: sn=lastName
zimbraGalLdapAttrMap: st=workState
zimbraGalLdapAttrMap: street,streetAddress=workStreet
zimbraGalLdapAttrMap: telephoneNumber=workPhone
zimbraGalLdapAttrMap: title=jobTitle
zimbraGalLdapAttrMap: whenChanged,modifyTimeStamp=modifyTimeStamp
zimbraGalLdapAttrMap: whenCreated,createTimeStamp=createTimeStamp
zimbraGalLdapAttrMap: zimbraCalResLocationDisplayName=zimbraCalResLocati onDisplayName
zimbraGalLdapAttrMap: zimbraCalResType=zimbraCalResType
zimbraGalLdapAttrMap: zimbraId=zimbraId
zimbraGalLdapAttrMap: zimbraMailDeliveryAddress,zimbraMailAlias,mail=ema il,email2,email3,email4,email5,email6,email7,email 8,email9,email10,email11,email12,email13,email14,e mail15,email16
zimbraGalLdapAttrMap: zimbraMailForwardingAddress=zimbraMailForwardingAd dress
zimbraGalLdapFilterDef: ad:(&(|(cn=*%s*)(sn=*%s*)(gn=*%s*)(mail=*%s*))(!(m sExchHideFromAddressLists=TRUE))(mailnickname=*)(| (&(objectCategory=person)(objectClass=user)(!(home MDB=*))(!(msExchHomeServerName=*)))(&(objectCatego ry=person)(objectClass=user)(|(homeMDB=*)(msExchHo meServerName=*)))(&(objectCategory=person)(objectC lass=contact))(objectCategory=group)(objectCategor y=publicFolder)(objectCategory=msExchDynamicDistri butionList)))
zimbraGalLdapFilterDef: adAutoComplete: (&(|(cn=%s*)(sn=%s*)(gn=%s*)(mail=%s*))(!(msExchHi deFromAddressLists=TRUE))(mailnickname=*)(|(&(obje ctCategory=person)(objectClass=user)(!(homeMDB=*)) (!(msExchHomeServerName=*)))(&(objectCategory=pers on)(objectClass=user)(|(homeMDB=*)(msExchHomeServe rName=*)))(&(objectCategory=person)(objectClass=co ntact))(objectCategory=group)(objectCategory=publi cFolder)(objectCategory=msExchDynamicDistributionL ist)))
zimbraGalLdapFilterDef: externalLdap Auto Complete:(|(cn=%s*)(sn=%s*)(gn=%s*)(mail=%s*))
zimbraGalLdapFilterDef: zimbraAccountAutoComplete: (&(|(displayName=%s*)(cn=%s*)(sn=%s*)(gn=%s*)(mail =%s*)(zimbraMailDeliveryAddress=%s*)(zimbraMailAli as=%s*))(|(objectclass=zimbraAccount)(objectclass= zimbraDistributionList))(!(objectclass=zimbraCalen darResource)))
zimbraGalLdapFilterDef: zimbraAccountSync: (&(|(displayName=*%s*)(cn=*%s*)(sn=*%s*)(gn=*%s*)( mail=*%s*)(zimbraMailDeliveryAddress=*%s*)(zimbraM ailAlias=*%s*))(|(objectclass=zimbraAccount)(objec tclass=zimbraDistributionList))(!(objectclass=zimb raCalendarResource)))
zimbraGalLdapFilterDef: zimbraAccounts: (&(|(displayName=*%s*)(cn=*%s*)(sn=*%s*)(gn=*%s*)( mail=*%s*)(zimbraMailDeliveryAddress=*%s*)(zimbraM ailAlias=*%s*))(|(objectclass=zimbraAccount)(objec tclass=zimbraDistributionList))(!(objectclass=zimb raCalendarResource)))
zimbraGalLdapFilterDef: zimbraResourceAutoComplete: (&(|(displayName=%s*)(cn=%s*)(sn=%s*)(gn=%s*)(mail =%s*)(zimbraMailDeliveryAddress=%s*)(zimbraMailAli as=%s*))(objectclass=zimbraCalendarResource))
zimbraGalLdapFilterDef: zimbraResourceSync: (&(|(displayName=*%s*)(cn=*%s*)(sn=*%s*)(gn=*%s*)( mail=*%s*)(zimbraMailDeliveryAddress=*%s*)(zimbraM ailAlias=*%s*))(objectclass=zimbraCalendarResource ))
zimbraGalLdapFilterDef: zimbraResources: (&(|(displayName=*%s*)(cn=*%s*)(sn=*%s*)(gn=*%s*)( mail=*%s*)(zimbraMailDeliveryAddress=*%s*)(zimbraM ailAlias=*%s*))(objectclass=zimbraCalendarResource ))
zimbraGalLdapPageSize: 1000
zimbraGalMaxResults: 100
zimbraGalSyncLdapPageSize: 1000
zimbraHsmAge: 30d
zimbraHttpNumThreads: 250
zimbraHttpSSLNumThreads: 50
zimbraImapBindOnStartup: TRUE
zimbraImapBindPort: 7143
zimbraImapCleartextLoginEnabled: FALSE
zimbraImapNumThreads: 200
zimbraImapProxyBindPort: 143
zimbraImapSSLBindOnStartup: TRUE
zimbraImapSSLBindPort: 7993
zimbraImapSSLProxyBindPort: 993
zimbraImapSSLServerEnabled: TRUE
zimbraImapSaslGssapiEnabled: FALSE
zimbraImapServerEnabled: TRUE
zimbraInstalledSkin: hotrod
zimbraInstalledSkin: steel
zimbraInstalledSkin: lemongrass
zimbraInstalledSkin: bare
zimbraInstalledSkin: beach
zimbraInstalledSkin: sand
zimbraInstalledSkin: yahoo
zimbraInstalledSkin: lavender
zimbraInstalledSkin: waves
zimbraInstalledSkin: sky
zimbraInstalledSkin: bones
zimbraLastLogonTimestampFrequency: 7d
zimbraLmtpBindOnStartup: FALSE
zimbraLmtpBindPort: 7025
zimbraLmtpNumThreads: 20
zimbraLmtpPermanentFailureWhenOverQuota: FALSE
zimbraLmtpServerEnabled: TRUE
zimbraLogHostname: emma.enc
zimbraLogRawLifetime: 31d
zimbraLogSummaryLifetime: 730d
zimbraLogToSyslog: FALSE
zimbraMailDiskStreamingThreshold: 1048576
zimbraMailPort: 80
zimbraMailProxyPort: 0
zimbraMailPurgeSleepInterval: 1m
zimbraMailReferMode: wronghost
zimbraMailSSLPort: 0
zimbraMailSSLProxyPort: 0
zimbraMailURL: /zimbra
zimbraMemcachedBindPort: 11211
zimbraMessageCacheSize: 1671168
zimbraMessageIdDedupeCacheSize: 3000
zimbraMtaAntiSpamLockMethod: flock
zimbraMtaAuthEnabled: TRUE
zimbraMtaAuthTarget: FALSE
zimbraMtaCommonBlockedExtension: asd
zimbraMtaCommonBlockedExtension: bat
zimbraMtaCommonBlockedExtension: chm
zimbraMtaCommonBlockedExtension: cmd
zimbraMtaCommonBlockedExtension: com
zimbraMtaCommonBlockedExtension: dll
zimbraMtaCommonBlockedExtension: do
zimbraMtaCommonBlockedExtension: exe
zimbraMtaCommonBlockedExtension: hlp
zimbraMtaCommonBlockedExtension: hta
zimbraMtaCommonBlockedExtension: js
zimbraMtaCommonBlockedExtension: jse
zimbraMtaCommonBlockedExtension: lnk
zimbraMtaCommonBlockedExtension: mov
zimbraMtaCommonBlockedExtension: ocx
zimbraMtaCommonBlockedExtension: pif
zimbraMtaCommonBlockedExtension: reg
zimbraMtaCommonBlockedExtension: rm
zimbraMtaCommonBlockedExtension: scr
zimbraMtaCommonBlockedExtension: shb
zimbraMtaCommonBlockedExtension: shm
zimbraMtaCommonBlockedExtension: shs
zimbraMtaCommonBlockedExtension: vbe
zimbraMtaCommonBlockedExtension: vbs
zimbraMtaCommonBlockedExtension: vbx
zimbraMtaCommonBlockedExtension: vxd
zimbraMtaCommonBlockedExtension: wav
zimbraMtaCommonBlockedExtension: wmf
zimbraMtaCommonBlockedExtension: wsf
zimbraMtaCommonBlockedExtension: wsh
zimbraMtaCommonBlockedExtension: xl
zimbraMtaDnsLookupsEnabled: TRUE
zimbraMtaMaxMessageSize: 10240000
zimbraMtaMyDestination: localhost
zimbraMtaRestriction: reject_invalid_hostname
zimbraMtaRestriction: reject_non_fqdn_sender
zimbraMtaTlsAuthOnly: TRUE
zimbraNotebookAccount: wiki@emma.enc
zimbraNotebookFolderCacheSize: 1024
zimbraNotebookMaxCachedTemplatesPerFolder: 256
zimbraNotebookPageCacheSize: 10240
zimbraNotifyBindPort: 7035
zimbraNotifySSLBindPort: 7036
zimbraNotifySSLServerEnabled: TRUE
zimbraNotifyServerEnabled: TRUE
zimbraPop3BindOnStartup: TRUE
zimbraPop3BindPort: 7110
zimbraPop3CleartextLoginEnabled: FALSE
zimbraPop3NumThreads: 100
zimbraPop3ProxyBindPort: 110
zimbraPop3SSLBindOnStartup: TRUE
zimbraPop3SSLBindPort: 7995
zimbraPop3SSLProxyBindPort: 995
zimbraPop3SSLServerEnabled: TRUE
zimbraPop3SaslGssapiEnabled: FALSE
zimbraPop3ServerEnabled: TRUE
zimbraRedoLogArchiveDir: redolog/archive
zimbraRedoLogDeleteOnRollover: TRUE
zimbraRedoLogEnabled: TRUE
zimbraRedoLogFsyncIntervalMS: 10
zimbraRedoLogLogPath: redolog/redo.log
zimbraRedoLogRolloverFileSizeKB: 102400
zimbraRemoteManagementCommand: /opt/zimbra/libexec/zmrcd
zimbraRemoteManagementPort: 22
zimbraRemoteManagementPrivateKeyPath: /opt/zimbra/.ssh/zimbra_identity
zimbraRemoteManagementUser: zimbra
zimbraReverseProxyAuthWaitInterval: 10s
zimbraReverseProxyDomainNameAttribute: zimbraDomainName
zimbraReverseProxyDomainNameQuery: (&(zimbraVirtualIPAddress=${IPADDR})(objectClass=z imbraDomain))
zimbraReverseProxyHttpEnabled: FALSE
zimbraReverseProxyHttpPortAttribute: zimbraMailPort
zimbraReverseProxyIPLoginLimit: 0
zimbraReverseProxyIPLoginLimitTime: 3600
zimbraReverseProxyImapPortAttribute: zimbraImapBindPort
zimbraReverseProxyImapSSLPortAttribute: zimbraImapSSLBindPort
zimbraReverseProxyImapSaslGssapiEnabled: FALSE
zimbraReverseProxyImapStartTlsMode: only
zimbraReverseProxyLookupTarget: FALSE
zimbraReverseProxyMailEnabled: TRUE
zimbraReverseProxyMailHostAttribute: zimbraMailHost
zimbraReverseProxyMailHostQuery: (|(zimbraMailDeliveryAddress=${USER})(zimbraMailAl ias=${USER})(zimbraId=${USER}))
zimbraReverseProxyPop3PortAttribute: zimbraPop3BindPort
zimbraReverseProxyPop3SSLPortAttribute: zimbraPop3SSLBindPort
zimbraReverseProxyPop3SaslGssapiEnabled: FALSE
zimbraReverseProxyPop3StartTlsMode: only
zimbraReverseProxyPortQuery: (&(zimbraServiceHostname=${MAILHOST})(objectClass= zimbraServer))
zimbraReverseProxySSLCiphers: !SSLv2:!MD5:HIGH
zimbraReverseProxySendImapId: TRUE
zimbraReverseProxySendPop3Xoip: TRUE
zimbraReverseProxyUserLoginLimit: 0
zimbraReverseProxyUserLoginLimitTime: 3600
zimbraSSLExcludeCipherSuites: SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA
zimbraSSLExcludeCipherSuites: SSL_DHE_DSS_WITH_DES_CBC_SHA
zimbraSSLExcludeCipherSuites: SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
zimbraSSLExcludeCipherSuites: SSL_DHE_RSA_WITH_DES_CBC_SHA
zimbraSSLExcludeCipherSuites: SSL_RSA_EXPORT_WITH_DES40_CBC_SHA
zimbraSSLExcludeCipherSuites: SSL_RSA_EXPORT_WITH_RC4_40_MD5
zimbraSSLExcludeCipherSuites: SSL_RSA_WITH_DES_CBC_SHA
zimbraScheduledTaskNumThreads: 20
zimbraSmtpHostname: localhost
zimbraSmtpPort: 25
zimbraSmtpSendAddMailer: TRUE
zimbraSmtpSendAddOriginatingIP: TRUE
zimbraSmtpSendPartial: FALSE
zimbraSmtpTimeout: 60
zimbraSoapRequestMaxSize: 15360000
zimbraSpamCheckEnabled: FALSE
zimbraSpamHeader: X-Spam-Flag
zimbraSpamHeaderValue: YES
zimbraSpamIsNotSpamAccount: XXX
zimbraSpamIsSpamAccount: XXX
zimbraSpamKillPercent: 75
zimbraSpamReportSenderHeader: X-Zimbra-Spam-Report-Sender
zimbraSpamReportTypeHam: ham
zimbraSpamReportTypeHeader: X-Zimbra-Spam-Report-Type
zimbraSpamReportTypeSpam: spam
zimbraSpamTagPercent: 33
zimbraTableMaintenanceGrowthFactor: 10
zimbraTableMaintenanceMaxRows: 1000000
zimbraTableMaintenanceMinRows: 10000
zimbraTableMaintenanceOperation: ANALYZE
zimbraVirusBlockEncryptedArchive: TRUE
zimbraVirusCheckEnabled: FALSE
zimbraVirusDefinitionsUpdateFrequency: 2h
zimbraVirusWarnAdmin: TRUE
zimbraVirusWarnRecipient: TRUE
zimbraXMPPEnabled: TRUE

that's quite an impressive respawn rate. methinks nginx should do a better job of missing memcached than that..

ps -ef |grep memcache
zmcontrol status
(is proxy/memcached reporting not running).

zmproxyctl stop
zmproxyctl start
see if that helps.

Thanks for your help :-)
Nothing is better, i still got more than 13000 lines in nginx.log in less than 3 seconds.
Here are the results of your suggested commands :

$ ps -ef | grep memcache
zimbra 8105 1 0 11:50 ? 00:00:00 /opt/zimbra/memcached/bin/memcached -d -P /opt/zimbra/log/memcached.pid
zimbra 29117 20697 0 14:25 pts/0 00:00:00 grep memcache

$ zmcontrol status
Host emma.enc
antispam Running
antivirus Running
imapproxy Running
ldap Running
logger Running
mailbox Running
mta Running
snmp Running
spell Running
stats Running

$ zmproxyctl stop
Stopping nginx
Stopping memcached

$ zmproxyctl start
Mon Jun 16 14:27:31 2008 Service archiving is not enabled. Skipping archiving
Mon Jun 16 14:27:31 2008 Rewrote: /opt/zimbra/conf/nginx.conf
nginx is running
memcached is running

I would hazard a guess and say your /etc/hosts file is incorrect. Look for the line beginning with:
127.0.1.1

and make sure it *doesn't* have your hostname or fqdn - it should just have localhost. your hostname/fqdn should only be on proper ip address line.

You were right :-) Lots of thank you for you !

My load average is now below 0.2 instead of 3.
No more error in nginx.log.

For the record, i had in the ipv4 part of /etc/hosts :
127.0.0.1 localhost
127.0.1.1 emma.enc emma
192.168.10.20 emma.enc emma

And now, i have :
127.0.0.1 localhost
127.0.1.1 localhost
192.168.10.20 emma.enc emma

By the way, could you explain me or point me to an explanation as to why i should just have localhost ?

See the bug fix in official nginx:
The potential bug incurred by "one_addr".
See the bug fix in nginx-zimbra:
https://bugzilla.zimbra.com/show_bug.cgi?id=54439

If u are the users before this bug fix, make sure that the memcache hostname in nginx.conf.memcache "servers" directive map to only ONE IP. For example, fix in your /etc/hosts.

I had a similar problem. Your tips helped me a lot!