This installment we will cover what connects the controller to the computer.
Disk controllers use a system bus to talk to your CPU and memory. It also determines the maximum speed your disk can talk to the computer. There may be as many as six different system busses in your computer. We are only interested in the ones that directly connect your disk controllers.
The oldest bus still in general use is PCI. You can still find them in your desktop and in servers though it is really on the way out. We are only covering PCI 2.0 32 bits wide running at 33 MHz. This allows for a theoretical top More >
Your servers are only as fast as the slowest part, hard drives.To feed other parts of the system we have to add lots of drives to get the desired IO single server can consume.
The basics of how hard drives work has been fundamentally static since the 70’s only refinements in technique and the core technologies have improved. You have a shaft or “spindle” attached to a motor. Disks or “platters” are attached to the spindle. The motor spins the spindle and the platters. Read/write heads controlled by actuator motors move across the surface with very precise motion and access the information More >
At least once a year I give a large talk on disk subsystems, IO and SQL Server. It’s a ground up from the nuts and bolts of how a hard drive works through SAN’s and Solid State Disks. The reasons I give this presentation so often is it is one of the most requested topics and one of the most misunderstood. The problem often lies in the fact the DBA may not know that much about different storage systems but they do know that it is very important do their jobs. With the rise of SAN, iSCSI and other storage solutions DBA’s have less and less control over the disk system that their SQL Server More >