PostgreSQL 10 High Performance - Third Edition

Disk controllers

One of the most critical aspects of PostgreSQL performance is also one of the easiest to overlook. Several hardware trends have made the disk controller seem less important now:

• Increasing CPU speeds and improved direct memory access (DMA) approaches make offloading disk work to a controller card seemingly less valuable. There is little chance that your controller will be any faster at previously expensive tasks such as RAID parity computation than your main system processor(s).
• Recent OS file system technology, such as Linux software RAID and ZFS, makes hardware RAID, with its often proprietary storage, seem less desirable.

Virtual machines and cloud deployments make the underlying disk hardware almost completely disconnected ...