Tmpfs for amavisd-new
This document gathers requirement and steps required to configure amavisd to use a ramdisk for its temporary data processing. The steps are specific to RHEL servers running Zimbra 6.x or higher.
Note
This is not a Zimbra feature. I've documented the steps here just for reference who require amavisd with tmpfs. Please check Bug 13607 and Bug 8081 for more details.
Requirement
Amavisd-new's speed may be limited by the speed and latency of your disk I/O, which can causes huge active mail queue, with a very limited delivery rate. Moving amavisd tmp directory to ramdisk will eliminate disk read/write operations. It can make a lot of difference in amavisd mail processing speed.
Pre-requisites
1. You need a kernel that is capable of creating and using a tmpfs filesystem 2.
Sizing
If you run n amavisd-new instances and each one accepts mails of $message_size_limit, then you need a tmpfs of size will be.
n * (1 + max(expansionfactor)) * $message_size_limit
Steps
/etc/fstab /dev/shm /opt/zimbra/data/amavisd/tmp tmpfs defaults,noexec,nodev,nosuid,size=150m,mode=750,uid=7509,gid=54322 0 0
Stop zmamavisdctl
mount /opt/zimbra/data/amavisd/tmp
Start zmamavisdctl
