Monitor Filesystem IO Calls for Messaging Server
(Doc ID 1351483.1)
Last updated on APRIL 15, 2020
Oracle Communications Messaging Server - Version 6.0.0 and later Information in this document applies to any platform.
Email is an I/O-intensive application. It is not just the throughput in terms of the amount of data -- because the IO operations tend to be relatively small (in terms of what modern IO systems are capable of) -- but the rate of operations (also called IOPS -- IO Operations Per Second). Therefore most email performance problems tend to be due to disk I/O bottlenecks.
There are tools to monitor disk I/O performance (such as the asvc_t column in iostat -xpn), but sometimes the bottleneck is in the filesystem rather than the lower level storage devices.
This article provides a DTrace script to monitor a few of the disk-IO-related syscalls used by some of the Messaging Server processes. This should be a basis for deciding whether your problem is related to the file system or disks storage or something else.