he ThinkSystem ST50 server supports Client HDDs and Enterprise Class HDDs. Client HDDs are designed for 8x5 operating environment whereas Enterprise Class HDDs are designed for 24x7 operating environment. Selecting the correct drive class will enable the critical areas of quality, functionality, performance, and reliability to be optimized for the target implementation. When using Client Hard Disk Drives, you agree to the following terms of service: Update the firmware once you receive the server according to the 'Lenovo Client HDD Upgrade for Windows and Linux' document in the download page: https://datacentersupport.lenovo.com/products/servers/thinksystem/st50/7y48/downloads/driver-list/component?name=Storage The use of the Lenovo Online SAS/SATA Hard Disk Drive Update Program is not supported. Maximum of 2 Client HDDs per server is supported Mixing Client HDDs with other drives is not supported. Only supported connected to the server's onboard 6Gbps SATA controller. RAID adapters and HBAs are not supported. Operational availability: 8 hours/day, 5 days/week. Workload rate limit: < 55 TB/year* Choosing the right drive type depends on the usage pattern. Improper use of Client HDDs (such as the workload rate exceeding 55 TB/year) will lead to significant risk and increase the drives failure rate. * The specifications for the product assumes the I/O workload does not exceed the average annualized workload rate limit of 55 TB/year. Workloads exceeding the annualized rate may degrade and impact reliability as experienced by the particular application. The average annualized workload rate limit is in units of TB per calendar year.