setting message queue size

["Nick Smith" <nick@computernick.com>]

Does anyone know where to set the message queue size for postfix? I know
where to set the mailbox size and message size limit etc, but I am getting
these error messages:

mailserver postfix/smtpd[474]: connect from murphy.debian.org[146.82.138.6]
mailserver postfix/smtpd[474]: NOQUEUE: reject: MAIL from
murphy.debian.org[146.82.138.6]: 452 Insufficient system storage;
proto=ESMTP helo=<murphy.debian.org>
mailserver postfix/smtpd[474]: warning: not enough free space in mail queue:
2762018816 bytes < 1.5*message size limit

mailserver postfix/smtpd[474]: connect from libranet.com[216.40.244.220]
mailserver postfix/smtpd[474]: NOQUEUE: reject: MAIL from
libranet.com[216.40.244.220]: 452 Insufficient system storage; proto=ESMTP
helo=<libranet.com>
mailserver postfix/smtpd[474]: warning: not enough free space in mail queue:
2762027008 bytes < 1.5*message size limit


where do I set the mail queue size?

Here is my main.cf if I helps:

debugger_command =
         PATH=/usr/bin:/usr/X11R6/bin
         xxgdb $daemon_directory/$process_name $process_id & sleep 5

# Other configurable parameters.
command_directory = /usr/sbin
daemon_directory = /usr/lib/postfix
smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
mydomain = computernick.com
myhostname = mailserver.computernick.com
mynetworks = 127.0.0.0/8 192.168.0.0/24
program_directory = /usr/lib/postfix
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, $mydomain, localhost.localdomain, localhost
# relayhost = superserver.computernick.com
relayhost = smtp.comcast.net
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
append_dot_mydomain = yes
mailbox_size_limit = 7500000000
message_size_limit = 7500000000
smtpd_helo_required     = yes
strict_rfc821_envelopes = yes

smtpd_recipient_restrictions =
        reject_invalid_hostname,
        reject_unknown_recipient_domain,
        reject_non_fqdn_recipient,
        permit_mynetworks,
        reject_rbl_client       list.dsbl.org,
        reject_rbl_client       multihop.dslbl.org,
        reject_rbl_client       sbl.spamhaus.org,
        reject_rbl_client       sbl.njabl.org
        reject_rbl_client       ipwhois.rfc-ignorant.org
        reject_rbl_client       opm.blitzed.org,
        reject_unauth_destination

TIA

nick
--
Computer Nick a.k.a. Nick Smith
Email - Nick@ComputerNick.com
Web - https://www.ComputerNick.com