Error 500: javax.servlet.ServletException: For DiskStore: Replicated_UM_EMAIL_ALIAS_CACHE
I'm running AEM Forms 6.5 JEE for WebSphere with the latest Service packs and hotfixes.
After running load/stress test on the server, I'm getting this error :

Due to which I'm unable to access my applications in AdminUI resulting my forms to not load.
Is this an expected behavior in heavy usage?
Can I delete the /tmp/adobews_* directory as a whole? this is just 151mb? What will be the impact of deleting the directory as a whole?
Note :- There is more than 5 GB of space left in the parent directory /app. still it is saying Critical disk usage.
Thank You in advance.