Postfix hangs why?

hi guys im having a problem with postfix, sometimes hangs up i check the server and web server is running ok & postfix seems to be running well, but can't send & receive email...

i check with netstat -tapun and i see lots of connections to the 25 port of the server about (20 connections)...

i check mail logs and all mail activity just dissapear around 06:25 (checked for 2 consecutive days)

then i check $cat /var/log/syslog | grep 06:25

Jun 25 06:25:57 ns24815 syslogd 1.4.1#17ubuntu7: restart.
Jun 25 06:25:57 ns24815 postfix/qmgr[3823]: DFE2C4073: from=<root@localhost>, size=641, nrcpt=1 (queue active)
Jun 25 06:25:57 ns24815 postfix/local[17275]: DFE2C4073: to=<xyz@xxxxxxx>, orig_to=<root>, relay=local, delay=0, status=bounced (unknown user: "ovh")
Jun 25 06:25:57 ns24815 postfix/qmgr[3823]: E417D4079: from=<>, size=2348, nrcpt=1 (queue active)
Jun 25 06:25:57 ns24815 postfix/qmgr[3823]: DFE2C4073: removed
Jun 25 06:25:57 ns24815 postfix/local[17275]: E417D4079: to=<xyz@xxxxxx>, orig_to=<root@localhost>, relay=local, delay=0, status=bounced (unknown user: "xyz")
Jun 25 06:25:57 ns24815 postfix/qmgr[3823]: E417D4079: removed
Jun 25 16:06:25 ns24815 courierpop3login: LOGIN, user=web8_faguilera, ip=[::ffff:80.32.189.84]
Jun 25 16:06:25 ns24815 courierpop3login: LOGOUT, user=web8_faguilera, ip=[::ffff:80.32.189.84], top=0, retr=0, time=0
Jun 26 06:25:01 ns24815 /USR/SBIN/CRON[15220]: (root) CMD (/usr/local/rtm/bin/rtm 28 >/dev/null 2>/dev/null)
Jun 26 06:25:01 ns2481Jun 26 14:48:31 ns24815 syslogd 1.4.1#17ubuntu7: restart.
Jun 27 00:06:25 ns24815 postfix/smtpd[26582]: warning: 201.254.169.158: hostname 201-254-169-158.speedy.com.ar verification failed: Name or service not known
Jun 27 00:06:25 ns24815 postfix/smtpd[26582]: connect from unknown[201.254.169.158]
Jun 27 00:09:54 ns24815 postfix/anvil[26585]: statistics: max cache size 3 at Jun 27 00:06:25
Jun 27 06:25:01 ns24815 /USR/SBIN/CRON[19891]: (root) CMDJun 27 11:39:35 localhost syslogd 1.4.1#17ubuntu7: restart.

what is this syslogd restart?????

i try to restart postfix and shows a error of could not rw on file... /var... so i try to restart the server with $reboot, and dont reboot for 5 minutes... so finally i have to hard reset...

what is happening...?

this is the output of postconf -n:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = yes
config_directory = /etc/postfix
disable_vrfy_command = yes
inet_interfaces = all
inet_protocols = ipv4
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
message_size_limit = 20240000
mydestination = /etc/postfix/local-host-names
myhostname = server1.xxxxx.com
mynetworks = 127.0.0.0/8
myorigin = /etc/mailname
recipient_delimiter = +
relayhost =
smtp_tls_note_starttls_offer = yes
smtp_tls_session_cache_database = btree:${queue_directory}/smtp_scache
smtp_use_tls = yes
smtpd_banner = $myhostname ESMTP $mail_name
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, reject_invalid_hostname, regexp:/etc/postfix/helo.regexp, permit
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination,reject_invalid_hostname,reject_non_fqdn_hostname,reject_non_fqdn_hostname,reject_non_fqdn_sender,reject_non_fqdn_recipient,reject_unknown_sender_domain,reject_unknown_recipient_domain,reject_rbl_client cbl.abuseat.org, reject_rbl_client sbl-xbl.spamhaus.org, reject_rbl_client bl.spamcop.net, reject_rhsbl_sender dsn.rfc-ignorant.org, permit
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem
smtpd_tls_auth_only = no
smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt
smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:${queue_directory}/smtpd_scache
smtpd_tls_session_cache_timeout = 3600s
smtpd_use_tls = yes
strict_rfc821_envelopes = yes
tls_random_source = dev:/dev/urandom
unknown_address_reject_code = 554
unknown_client_reject_code = 554
unknown_hostname_reject_code = 554


UPDATED:

THE SYSTEM HANGS EVERY TIME IS RUN "SYSKLOGD" it is in /etc/cron.daily, but no idea how to fix it...
i deleted gzipped logs on /var/log/ a few days ago... hope that doesn´t matter...

any help would be apprecciated

 

i didn´t post it but sure it is included...

UPDATED:

I've fixed some hard disk inodes problems with links & log files, so when sysklogd was executed, it tried to access those files crashing the system & hanging postfix.

thk u very much u all