It’s a RAID!
External storage devices are rapidly gaining adoption as a way to easily add disk space to your system. Is it worth it to build your own?
Lately, we’ve been seeing a lot of external storage devices coming out of the big vendors. While these are generally very solid devices, some are on the pricey side. When you need more storage in a hurry, cost is often no object and you’ll gladly drop the extra coin to get the space right now.
If, however, you’ve got a little spare time, you can put together your own external storage device with a minimum of hassle. But there are a lot of storage enclosures and drives out there vying for your attention. What will work best for you?
Internal or External?
If you’re comfortable working inside your computer, it’s pretty easy to add another hard drive. Many recent motherboards even include onboard RAID controllers. The drawback, though, is that you need the appropriate cables available, and if you have a lot of drives in your case, heat may become an issue.
On the other hand, external devices require some extra desk space, as well as a power cord to be plugged into the wall, power strip or UPS.
The most popular interfaces used to connect your storage device to your computer are FireWire (both 400Mbps and 800Mbps variants) and USB 2.0. Both USB 2.0 and FireWire are great choices for portability. However, the hard drives inside your storage device are hobbled by the bridge chip that acts as the intermediary between the SATA or IDE hard drive(s) inside the device and the USB and/or FireWire connection. That said, both FireWire and USB 2.0 are fast enough to handle a DV stream. (The performance hit will come when you are rendering effects or completed projects.)
An emerging interface is eSATA (external Serial ATA). This connection is quite similar to the Serial ATA that may already be in your system, but is more electrically robust. The advantage of eSATA is that it is as fast as SATA, which is significantly faster than either USB 2.0 or FireWire.
Another increasingly popular interface is gigabit Ethernet. Technically, a storage device attached via Ethernet is classified as an NAS (network attached storage) device, but these devices are worth discussing in this context. An added benefit of using an NAS is that you can easily access the drive from any computer on your network. For maximum performance, however, you need a gigabit Ethernet router and gigabit Ethernet ports on all of the computers from which you want to access the NAS. (You could also access the device over your Wi-Fi, but its performance potential would be lost.)
Inside the Box
As far as interfaces go, the majority of storage enclosures that you can purchase include several choices of external interface (that gets connected to your computer or LAN). Some cases include combinations of USB, FireWire and eSATA for added flexibility.
The next question: which drive form factor? The majority of cases accommodate 3.5″ (desktop) drives, but there are some super-svelte cases out there that handle 2.5″ (laptop) drives. Laptop drives have neither the performance nor capacity of desktop drives, and they also cost quite a bit more on a cost per gigabyte basis, but if space is really at a premium, they might be the only choice worth considering for you.
The internal interface of the device dictates the types of hard drives you will buy to install in the case. Your choice will most likely be either ATA or SATA, but some cases handle both. You also want to pay attention to the RAID levels that your device can handle. The RAID levels of primary importance to video editors are RAID 0 (striping) and RAID 5 (spanning with distributed parity). However, a number of the controllers in these cases can also access your drives as a JBOD (just a bunch of disks – which combines a number of disks together to appear as a single volume to your computer). If one drive fails on a RAID 0, you’ll lose all of your data. If you have a failure on a JBOD, only the data on the affected disk will be lost. If a disk fails on a RAID 5 array, you will still be able to access all of your data (performance will be affected), although you will need to replace the failed drive and set the array to rebuild itself as soon as possible to get your array out of a degraded state.
Depending on the device you have purchased, you may need to have a card installed in your computer. This will most likely be the case for eSATA, though eSATA ports will become much more common on future motherboards and pre-assembled computers.
Once you get your external case, you have to populate it with drives. When everything is connected and you power up the device for the first time, you’ll configure the disks and format the device. (Procedures vary, but you’ll be using either a Web browser, a setup menu that you access while your computer boots, a specialized piece of software shipped with your enclosure or downloaded from the Web, the Windows disk management tool or the Mac OS Disk Utility.)
If you’re up to the task, we think you’ll find building your own external storage to be quite rewarding.