Solid-State Drives: Get One Already!

Brian Trapp — Tue, 18 Mar 2014 21:22:54 +0000

I've been building computers since the 1990s, so I've seen a lot of new technologies work their way into the mainstream. Most were the steady, incremental improvements predicted by Moore's law, but others were game-changers, innovations that really rocketed performance forward in a surprising way. I remember booting up Quake after installing my first 3-D card—what a difference! My first boot off a solid-state drive (SSD) brought back that same feeling—wow, what a difference!

However, at a recent gathering of like-minded Linux users, I learned that many of my peers hadn't actually made the move to SSDs yet. Within that group, the primary reluctance to try a SSD boiled down to three main concerns:

I'm worried about their reliability; I hear they wear out.
I'm not sure if they work well with Linux.
I'm not sure an SSD really would make much of a difference on my system.

Luckily, these three concerns are based either on misunderstandings, outdated data, exaggeration or are just not correct.

SSD Reliability Overview

How SSDs Differ from Hard Drives:

Traditional hard disk drives (HDDs) have two mechanical delays that can come into play when reading or writing files: pivoting the read/write head to be at the right radius and waiting until the platter rotates until the start of the file reaches the head (Figure 1). The time it takes for the drive to get in place to read a new file is called seek time. When you hear that unique hard drive chatter, that's the actuator arm moving around to access lots of different file locations. For example, my hard drive (a pretty typical 7,200 RPM consumer drive from 2011) has an average seek time of around 9ms.

Figure 1. Hard Drive

Instead of rotating platters and read/write heads, solid-state drives store data to an array of Flash memory chips. As a result, when a new file is requested, the SSD's internal memory can find and start accessing the correct storage memory locations in sub-milliseconds. Although reading from Flash isn't terribly fast by itself, SSDs can read from several different chips in parallel to boost performance. This parallelism and the near-instantaneous seek times make solid-state drives significantly faster than hard drives in most benchmarks. My SSD (a pretty typical unit from 2012) has a seek time of 0.1ms—quite an improvement!

Reliability and Longevity:

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