I am running Catalina on a Mac Pro (trashcan) QuadCore Xeon with 32 GB RAM. Run 1 Virtual Guest Windows 10 fully patched. Since the upgrade to 11.5.5 DIsk and system access is terrible, with the spinning wheel of death constantly. Guest is Running on RAID 1 Array of 2 -2tB 64 MB Cache drives and is only thing on the array. Was running disks as SCSI in Fusion going to try SATA next. Its a fairly small guest with 2 cores 6 GB RAM and about 200 GB drives. Any ideas?
I presume the performance previously on the RAID array was ok?
First thing I'd do is check the raid array smart status and make sure you don't have a failing disk. Second, if you use third-party RAID drivers or software, i'd make sure that it's 11.5.5 compatible.