Saturday, November 22, 2008

Winter Musings: November 2008. Data Storage I: NAS, USB, SATA...

Data storage seems to be a hot topic these days as RAW format files increase in size, cameras pack denser sensors, and adoption of digital capture is approaching saturation in all realms of the photography business. Issues like capacity, workflow, and processing speed are things we now have to deal with. Topics covered here will be internal versus external drives and USB/Firewire or networked storage.

Please keep in mind that a variety of factors can affect computer performance like how old your processor is, how much RAM you have, how many applications you have running simultaneously, file fragmentation, free hard drive space, and how long you have been running the same OS installation.

Internal or External?
If you like waiting around for images to load then continue using external USB or FireWire hard drives as your primary working disk. On the other hand. If you believe time is money, install internal drives and take advantage of your computer's SATA controller. Here's why. The slowest variety of SATA is spec'd to be almost 3x faster than USB2.0 and FireWire400. It is 50% faster than FireWire800. Last I checked, it is much easier finding the faster SATA II drives which is 6x and 2x faster than USB and FireWire, respectively. These figures hold even when taking into account protocol overhead which reduces the overall data rate. Unless you reguarly switch your USB drive between computers it is better to go with an internal drive.

Most computers purchased within the last 4 years have SATA controllers. You might be nervous about cracking open the computer chassis to perform the installation, but it really is easy as pie these days. All it takes is a screwdriver and the instruction manual telling you where to plug cables into the motherboard. Once powered on, format the new drive and you are ready to go. Your drive will automatically take on a lettered drive designation along side your other drive(s). An added benefit is that internal drives cost less.

NAS or USB/FireWire?
A NAS (network attached storage) is a device with one or more hard drives and (often) an embedded computer controller. Some may offer advanced features like FTP, access to files via a browser, multi user administration, streaming media services, RAID support, the list goes on. At its heart, every available consumer NAS is a basic file server meaning it provides transparent access to files that may be stored on another physical machine. The main benefits are the ability to share data between any computer on the network and the rate of transfer.

Why should you consider a NAS?
There are three reasons I have a NAS. At some point your computer hard drives will fill with files you do not use frequently like 3+ year old wedding images. It is necessary to off load them somewhere safe yet accessible in case you need it for a project later on. Maybe you also want to maintain temporary backup copies while you work in case your internal hard drive should fail. You can also use the NAS to store things like documents and music files so you can access them from the workstation or laptop with swapping plugs and cables.

These devices increasingly come standard with Gigabit Ethernet ports (10x faster than standard Ethernet) which is handy when transferring large amounts of data like image files. Raw data rates approach SATA speeds which is much faster than USB. Speed is a huge motivating factor as is built in redundancy. With hard drives so cheap, you can buy a multi drive NAS that can be configured as a RAID to protect your data. There are very few USB/FireWire RAID options. More on this in the next post.

Install internal SATA drives whenever possible, they will provide the best throughput for images that are actively accessed or maintained in a library like Bridge, Lightroom, or Aperture. They are also cheaper than external options. Network your workstation to a Gigabit Ethernet enabled NAS instead of using USB drives and be sure to use Gigabit Ethernet routers and switches. Configure the NAS to support Jumbo Frames to maximize network throughput.

I have decided to split this Winter Musing into two posts for November because it covers such a broad range of data-related topics. In the next post I will cover data archiving.

FYI, I am due an upgrade but run WindowsXP Pro SP2 on a 3.0 GHz Pentium 4 with 3GB of RAM. I have 4 internal hard drives: 250GB for applications, temp files, and OS, 250GB for images, and two 500GB SATA I drives for currently active libraries. I also have a Lenovo T60 laptop sporting a Core2Duo, 3GB of RAM and a 100GB hard drive. NAS-wise there is a 250GB Buffalo Linkstation which I use for shared files and a 1TB Buffalo Terastation configured as a RAID5 for my image archives. I just ordered a 500GB Netgear ReadyNAS Duo which will be my new RAID1 file server. Another RAID5 is in the works too because the Terastation is running short on room.

Firewire (IEEE-1394). Apple's external serial bus standard intended for use with professional A/V equipment. This technology was favored for its high data rates. The two most common implementations transfer data at 400 Mb/s and 800 Mb/s.

Gigabit Ethernet. A networking standard that supports data transfers at 1Gb/s. Also known as 1000Base-T or IEEE 802.3ab.

NAS. Network attached storage which is simply mass data storage accessible via a computer network - commonly Ethernet.

RAID (Redundant Array of Inexpensive Disks). A configuration where multiple hard drives are linked to provide a larger overall storage space and data protection. There are several versions including RAID 0, 1, 5, 6, 10

SATA (Serial ATA or Serial Advanced Technology Attachment). A fast internal computer data bus technology that hard drive makers have adopted and built into modern workstations. It replaces PATA, EIDE, and IDE technologies. Currently exists in 2 flavors: 1.5 Gb/s and 3.0 Gb/s.

USB (Universal Serial Bus). A simple and ubiquitous external attachment method for all sorts of computer peripherals like flash memory, printers, webcams, hard drives, etc. The main selling point was the ability to hot-swap a peripheral without restarting the workstation. Competes with the Firewire standard. These days most USB devices are USB 2.0 and transfer at rates of up to 480 Mb/s

Winter Musings are monthly posts between November and February. They cover a range of topics related to wedding photography with couples and photographers in mind. I hope you will tune in next month. Comments and requests are appreciated!