Workstation Disk Drives – Theory & Practice

Workstation Disk Drives – Theory & Practice

This article is part of the component selection series

When building a workstation, you will want to make sure that you take into account your I/O needs – as this is the area that will most affect system performance after your choice of CPU and System Memory. Hard drive performance is often overlooked due to a lack of understanding of what each of a typical drive’s specifications mean with regards to performance. This guide serves as an introduction to performance workstation I/O recommendations and concepts. We introduce you to the idea of the “Rule of 3” – 3 System Drives that serve differing needs within your system to make accessing and managing your data easy. For the sake of simplicity, we will assume your I/O controller is set to AHCI mode, you are a Microsoft Windows user, and ignore RAID arrays for the time being (we save this for another article). These recommendations are for late 2012/early 2013, however the lessons here remain the same as drive sizes and speeds increase until another paradigm shifting I/O technology in a similar vein to SSDs is released.

Primary Hard Drive – SSD
For maximum system performance, you will want your primary drive (the drive you install your operating system to) to be an SSD, which stands for Solid State Drive. This drive most commonly uses NAND flash memory of the MLC variety to store your data.  They have much faster Read/Write speeds than traditional magnetic disks and can significantly improve system performance.  Most manufacturers’ drives are now using the SATA III interface, which allows for a maximum speed of 600MB/s on the bus.  It is still worthwhile to purchase a SATA III drive as they are backward compatible with previous SATA specifications, however you will be limited to whatever bandwidth is provided by the SATA revision you are using. Spending between $100-$300 is appropriate for a drive to serve this need, with a drive capacity between 120GB and 256GB being sufficient. Since you are installing only your operating system (10-40GB) and a few applications (2-4 @ 10-20GB each – adjust accordingly by need/capacity) that require speed, you do not need an overly large capacity. It is a rule of thumb to not exceed more than 80% of the drive’s capacity with data when using an SSD, as sometimes you can experience a slowdown in performance as a result. Recommended brands are Intel, Crucial, and Samsung as they make highly regarded SSDs with very fast performance.

Secondary Hard Drive – High RPM Magnetic Disk Drive and/or Large Disk Cache (SSD someday in the future)
The drive decision in this category is determined by what you want to do with your system as well as your budget. The goal of this drive is to be high performance with a larger capacity to make up for high $/per GB of storage with SSDs. This drive’s primary purpose is to run your applications that are not as critical as the ones installed on the SSD, and your computer games library. The decision for this drive can go in one of two directions: 1) Purchase a high RPM disk such as a Western Digital Velociraptor ( 10,000RPM w/ 64MB Cache) with a capacity between 500GB-1TB. The performance increase from 7200RPM to 10,000 RPM is significant and warrants the cost higher cost of the drive (Between $149-$289). This is the pricier option; however the performance of the drive in sequential reads is high and is a good drive if you do a lot of gaming (install your games to this drive – not the SSD, as you now have the space to install multiple games without ruining your load times – this option is much faster than if they were on a large capacity storage drive with a slower RPM)  2) The second option is to purchase the largest capacity & cache drive you can afford from the Western Digital Caviar Black line. The lowest price 7200RPM 64MB Cache drive is $90 for 500GB of storage. While option #2 is not as fast as option #1, you still get the capacity you need to store the majority of your applications and the performance is “good enough” while being relatively inexpensive in comparison. You do not need nor want a drive much larger than 1TB in this category, as the amount of time to format the drive becomes an issue, as well as having unnecessary capacity begin to cannibalize the purpose of hard drive #3. It is better to spend the money on the smaller capacity drive with the higher speed – as speed has priority over capacity in this category. In time, this disk will most likely become an SSD as the price decreases with time while they grow in capacity.

Tertiary Hard Drive – Storage Hard Drive (Maximum Capacity)
The purpose of this drive is to store all of your content – movies, music, downloads, system backups etc. It is the “digital dumping ground” and stores everything that needs to be archived and is not used on a frequent basis or does not have large I/O needs. Thus, the features we are looking for from a Hard Drive in this category are: Stability/Longevity/Capacity. We want to make sure this drive is as stable and long lasting as possible (as important things are backed up to it). This means we must consider the drives mechanical parts that are prone to wear & tear. Generally, lower RPM hard drives last longer than higher RPM hard drives, as things like bearings and read heads tend to wear out more slowly. There is also less danger of a head crash wiping out a large portion of the disk, as it is spinning slower than a faster disk. Look for a drive that has a long warrantee in case it fails earlier (this is bad), so you can have it physically replaced for free– hopefully a data recovery service can get back the files you’ve stored on your drive – but this can be a pricy option (more on storing backups in multiple locations to prevent this scenario later).  Purchase the largest drive you can afford in the 5400RPM category. Some manufacturers are selling drives that operate at 5900RPM – this is fine (the main point is they are not 7200RPM drives). Cache isn’t as much of a factor here (the more the merrier), although if you can, try to find a drive that has good performance on sequential reads as you will be dealing with large contiguous files on this drive in most cases. Capacity ranges from 2TB-4TB are appropriate for this area. Western Digital Caviar Green hard drives are recommended, as they have power saving features and firmware designed specifically to handle tasks that we are using this disk for. A 2TB Caviar Green 64Mb Cache can be found online for as little as $110. Intellipower is WD marketing speak for variable rate rotational speed (5400-5900 or by some accounts as low as 5000).

Conclusions
The lessons here today will get you started on selecting the appropriate disks for the tasks you have at hand.  We personally recommend and use Western Digital Hard Drives as they have a quality warrantee that the company honors and their drives are built solidly. However – everyone has an opinion on drives from each drive manufacturer – pick whatever works best for you keeping in mind the key points of what this drive is trying to achieve for your workstation. It is worthwhile to consider the disk utilities provided by the manufacturer to make using your disks in the way you desire easier. This is yet another reason for the recommendation of WD drives, as they have excellent tools you can use to low level format your drives. IBM/Hitachi used to have the best disk utilities (their drives have both a good and bad reputation), but WD has recently bought them. Selecting all of your drives from the same manufacturer means that you can perform all of your management tasks on the drives without having to change disk software. There are some risks involved as a consequence of this (bad batch of drives, similar rates of failure, exposure to manufacturing defects during a generation / platter runs), but for a personal workstation these factors are of minimal impact. We have not bothered to discuss a backup strategy here or any redundancy as it will be assumed that you understand what/how to back up your important information. These concepts will be discussed in full in a future article.

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