HP proliant cache module failure

Question

In our windows server environment, we often get the alert for HP servers that storage cache module has failed. What exactly is the function of cache module?

Answer 1

Unfortunately, you are neither mentioning a specific server model nor a specific controller, thus I'm assuming Smart Arrays here. HP/HPE Smart Array RAID controllers provide a battery-backed cache to e.g. temporarily store data before transferring them to disks. The cache is DRAM, thus it's a lot faster than typical disk drives, and this speeds up e.g. write operations.

Let's go one step back: Once a data write to the cache is completed, the cache must be able to protect the data in case of a power loss before the data has been transferred to the drives. This happens using a battery, and the battery is normally what fails after some time which leads to alerts or failure reports, because you might be on risk when using a non-battery-backed cache. If this does not apply for you, you should provide a specific failure message here.

The HP document Smart Array technology: advantages of battery-backed cache describes the details of the cache in detail.