I have a very busy postfix server that acts as a relay. It gets mails
from an application and then forwards the mails to the delivery servers
on local LAN
The application can send mails at rate of upto 600 mails per second
Postfix has been configured to accept mails all that quickly, but the
delivery is very poor until inflow stops. Only around 20-50 mails per s
Once the app completes the inflow, then the mails are cleared at a rate
of 1000 mails per second
Why ?
Is there a contention on the queue manager when the inflow is too quick ?
Postfix version 3.0.1 on Centos 7.2
postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
always_add_missing_headers = yes
bounce_queue_lifetime = 5d
bounce_template_file = /etc/postfix/bounce.cf.default
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
compatibility_level = 2
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
default_destination_concurrency_limit = 500
default_process_limit = 500
disable_mime_input_processing = yes
disable_vrfy_command = yes
hash_queue_depth = 1
hash_queue_names = deferred, defer, hold
header_checks = regexp:/etc/postfix/header_checks
html_directory = no
in_flow_delay = 0s
inet_interfaces = 127.0.0.1
inet_protocols = all
lmtp_destination_concurrency_limit = 30
lmtp_line_length_limit = 9900000
mail_owner = postfix
mailbox_size_limit = 52783082
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_queue_lifetime = 5d
message_size_limit = 52783082
meta_directory = /etc/postfix
minimal_backoff_time = 30s
mydestination = XXX
myhostname = XXX
mynetworks = /etc/postfix/mynetworks
newaliases_path = /usr/bin/newaliases.postfix
qmgr_message_active_limit = 200000
qmgr_message_recipient_limit = 200000
queue_directory = /dev/shm/postfix
readme_directory = /usr/share/doc/postfix-3.0.1/README_FILES
relayhost = [X]
sample_directory = /usr/share/doc/postfix-3.0.1/samples
setgid_group = postdrop
shlib_directory = /usr/lib64/postfix
smtp_connection_cache_on_demand = yes
smtp_connection_cache_time_limit = 300s
smtp_line_length_limit = 9900000
smtpd_client_connection_count_limit = 0
smtpd_client_connection_rate_limit = 0
smtpd_recipient_limit = 3000
smtpd_recipient_restrictions = permit_mynetworks,
permit_sasl_authenticated, check_client_access
cidr:/etc/postfix/relay_allowedips, reject
smtpd_restriction_classes = check_env_from
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_local_domain =
smtpd_sasl_security_options = noanonymous
smtpd_sender_login_maps = hash:/etc/postfix/smtpd_sender_login_maps
smtpd_sender_restrictions = permit_mynetworks, check_client_access
cidr:/etc/postfix/permit_sender_ip, reject_sender_login_mismatch, permit
transport_maps =
cdb:/etc/postfix/bounce_transport,cdb:/etc/postfix/suppresslist,hash:/etc/postfix/transport,regexp:/etc/postfix/transport_regex,hash:/etc/postfix/emm_transport
unknown_hostname_reject_code = 550
unknown_local_recipient_reject_code = 550
virtual_alias_maps = hash:/etc/postfix/vmap
virtual_mailbox_base = /var/spool/mail
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