Performance Support

Storage: Disk Drive Types, Performance & Costs

TranscriptWhen it comes to disk storage there are several different types of disk drives. And each of these different disks have individual specifications. Some are better suited for budget conscious areas where high performance is a less of a concern, while others are best suited for high performance needs where we might be willing to spend the extra money, and there are lots in between. Let’s have a look at some of the most common disk drive types and the associated performance and cost of each.

First how do we define performance in the area of disk drives. Two of the main measures of performance are rotational speed, for example 10,000 or 10K RPM disk, and the other is the measure of Input/Output Per Second or IOPS. The faster the disk spins the faster the data is read or written and IOPS is a measure of just how much input and output a certain disk can process in one second. Higher numbers in both cases typically equate to higher performance. Some of today’s heaviest workloads demand very high IOPS from the disk subsystem. Implementing a system with high IOPS requirements on a system that cannot meet those needs will result in serious performance issues.

The disk types that we want to cover in this session are Serial ATA or SATA, Serial Attached SCSI or SAS, Fibre Channel (FC), Solid State Disk (SSD). Serial ATA or SATA has the lowest IOPS but also has the lowest cost. A 7,200 RPM drive will produce about 80 IOPS and a 10K drive will produce about a 110 IOPS. Still in use for applications where cost per gigabyte of storage is more important than high performance.

The next disk type is Serial Attached SCSI or SAS. This is a mid to high IOPS and mid to high cost disk. A 10K drives for SAS produce about a 120 IOPS while the 15K drives can do about a 160 IOPS. The SAS disks are growing in market share for enterprise class workloads and make up a large majority of the enterprise class disk being sold today.

Fibre Channel or FC has a very high IOPS but also very high cost. 10K drives can produce about a 140 IOPS while 15K drives can do about a 180 IOPS. This is still the standard for the heaviest disk workloads and where cost per gigabyte of storage is less important than performance.

The last drive type that we want to cover in our session today is Solid State Disk (SSD). While SSD is not exactly a spinning disk, it still should be covered here. There is no RPM rating; data on an SSD is basically stored in memory within the SSD instead of on disk platters. They can produce extremely high IOPS and they're very costly. Approximately ten times more expensive than traditional disk types. IOPS ratings can vary but in the range of 5,000 to 10,000 is not abnormal. This is not a traditional disk and is used for very specific workloads and purposes, very high cost but in certain cases it does make a lot of sense.

That’s disk performance, thanks for watching.

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