Really increase productivity 1s?

Question

1C-Enterprise

There is a terminal server on it spinning 6 databases, each 12-15GB, about 30 users simultaneously working with databases. It costs SQL IBM DB2, 1s version 8.2. The server itself is: Platform SuperMicro SYS-6018 DDR4 / Hard drive Hitachi SATA-III 2Tb HUS724020ALA640 (7200rpm) 64Mb 3.5 "4 pcs / Memory SuperMicro 8Gb DDR4 DIMM ECC Reg PC4-17000 CL15 4 pcs. The problem is that the databases load hard drives very heavily, namely the write speed (sometimes the value under 500 takes off), 1raid is assembled from hard drives (why not 10 questions to the manager ...), and users complain after 2-3 hours about the slow work 1s. Today we tried to balance and distribute the CPU resource among users, we did not see much growth. I'm waiting for advice)))

Answer 1

If you are sure that the HDD I/O is the bottleneck, then the logical solution is to set the SSD as a cache in front of the HDD. This can be implemented in various ways: on Linux it is easily done in software, on other Windows only in hardware with hardware support (modern cissets from Intel can do this).
Here is an obvious solution: With such insignificant volumes, you need to safely throw away the HDD and install an SDD, for 120 GB the price will be quite acceptable.