These warnings suggest a performance problem with the CPU and disk bottlenecks.
If you are running very intensive processes, you should see these warnings go away after they finish. However, if you keep seeing them continuously, I recommend going deeper and analyzing the performance.
Analyzing the performance takes time, and it's not always easy for non-experts. There is a great series of articles written in this community that can help with this:
https://community.intersystems.com/post/intersystems-data-platforms-capa...
If you don't want to go through all these series and can easily increase the system resources, it would be an easy way to probe and solve the problem ;-). What I mean by increasing system resources is by adding more CPUs and faster disks. Nowadays, with Virtual machines and cloud systems, this is quite simple.
And let me insist again, if this is a production system, you may want to open a WRC problem for extra help. Having the disk too stressed will end in User/Application pauses.
Ups! I just realized you wrote the system is Caché and not Iris. So, instead of the messages.log, you should read cconsole.log. Instead of ^SystemCheck, it would be ^Buttons, and, instead of ^PerformanceCheck, it will be ^pButtons.
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@Dmitry Maslennikov , WIJ file of 8GB means that the system wrote 8GB of cache buffers. This doesn't have to be a bad sign by itself and can be perfectly normal.