That link (I removed it because it looked like spam) said that defragmentation can make a hard disk slower (in fact: not at all or hardly noticeable for an SSD) and advertised a Windows program to keep it defragmented. That's a bad idea for an SSD, and very unlikely to be the cause of slower performance on a webserver. It could even be a Linux server for all we know.
You'll have to analyse the cause of the slowness, or if you can't find that yourself, hire an expert or a company.
It can be that you need another server or more RAM in the server or a faster network or optimised settings in the server, the VM or the application.
But don't exclude the option that it's just a bad application that slows down because it doesn't correctly handle the increasing amount of stored data.
I am using 10 VM each for every group company and each has their own application installed with SQL database, AV, and standard applications
I have 4 TB SSD drive with quad core IBM server with 16 GB ram
It been 3 months and users have begun to notice slow performance in their application, What Precaution should i take
Irrelevant link removed by moderator.