ESA FAQ: How many messages can the ESA/SMA retain in its mail queue?

Introduction

This document describes the mail queue size and an approximate number of messages that can be retained on the Email Security Appliance (ESA) or Security Management Appliance (SMA).

How many messages can the ESA/SMA retain in its mail queue?

Under certain circumstances, it might be necessary for the appliance to store messages for delivery at a later time. Based on an average message size of 15 KB (15,360 bytes), this table summarizes how many messages each model of the ESA and the SMA can retain and the corresponding mail queue size:

In order to determine the exact mail queue size of your appliance, run the command ipcheck from the CLI on your appliance.  The mail queue size is listed in the output.

Example output from a C600V:

myesa.local> ipcheck

Ipcheck Rev 1
Date Thu Nov 21 21:47:34 2019
Model C600V
Platform vmware (VMware Virtual Platform)
MGA Version Version: 13.0.0-314
Build Date 2019-09-21
Install Date 2019-10-14 17:40:45
Burn-in Date Unknown
Serial No. 420DE3B51AB7aabbccdd-9F04aabbccdd
BIOS Version 6.00
RAID Version NA
RAID Status Unknown
RAID Type NA
RAID Chunk Unknown
BMC Version NA

Disk 0 500GB VMware Virtual disk 2.0 at mpt0 bus 0 scbus2 target 0 lun 0
Disk Total 500GB

Root 4GB 6%
Nextroot 4GB 6%
Var 400MB 5%
Log 400GB 7%
DB 12GB 0%
Swap 8GB
Mail Queue 70GB

RAM Total 16384M


NIC Management 00:50:56:88:11:ee
NIC Data 1 00:50:56:88:88:88
NIC Data 2 00:50:56:88:55:aa

PS1 Unknown
PS2 Unknown

Key 310day, Data Loss Prevention
Key 310day, External Threat Feeds
Key 310day, File Analysis
Key 310day, File Reputation
Key 310day, Graymail Safe Unsubscription
Key 310day, Intelligent Multi-Scan
Key 310day, IronPort Anti-Spam
Key 310day, IronPort Email Encryption
Key 310day, IronPort Image Analysis
Key 310day, McAfee
Key 310day, Outbreak Filters
Key 310day, Sophos
Key 31365day, Bounce Verification
Key 31365day, Cloud Administration
Key 31367day, Incoming Mail Handling

Note: You will need to adjust the theoretical numbers based on your average message size and mail flow for your environment.

Please see the Cisco Security > Cisco Email Security Product Support page for current hardware models and further information regarding each specific model. 

Related Information

• Cisco Email Security Appliance Data Sheet
• x95 Security (ESA, WSA and SMA) Solution Overview
• Cisco Products and Services > Security > Cisco Email Security
• End-of-Sale and End-of-Life Announcement for the Cisco x170 and x80 Email, Web, and Content Security Management Accessories
• End-of-Sale and End-of-Life Announcement for the Cisco Email, Web and Security Management x90 Hardware Appliances
• Technical Support & Documentation - Cisco Systems