Reposted from http://www.bhphotovideo.com/explora/video/tips-and-solution/hard-drive-solutions-video-editing-studios
Video editing is one of the most demanding tasks you can execute on a computer. A modern video-editing program such as Adobe Premiere requires high performance from the processor, RAM memory, GPU (if using GPU acceleration), as well as storage drives. Choosing a fast storage solution can be a little tougher than picking the fastest computer processor, as there are more tradeoffs involved. The largest drives aren’t always the fastest, and speeds can vary a great deal. This guide was created to help you choose the right storage drive (or drives) for your editing needs, from the small to the large.
How much bandwidth do you need?
“The first step in choosing a drive is to determine how much storage space you need, as well as how fast your data can be stored and retrieved.”
The first step in choosing a drive is to determine how much storage space you need, as well as how quickly your data can be stored and retrieved. The biggest determining factor is what codec and resolution you will be editing in primarily, since the amount of space that different video codecs occupy varies widely. 1080p ProRes HQ, a popular editing codec, will set you back about 112GB an hour, whereas 1080p AVCHD only takes up about 11GB.
It’s also important not to confuse bits and bytes. Most codecs rate their speed in bits per second, whereas most hard drives publish their speeds in bytes per second. XDCAM EX’s 35Mb/s is actually only 4.5MB/s. A handy tool for determining the amount of bandwidth you need is the AJA DataCalc app, which is available for Windows and Mac at AJA’s website. It’s also available for iOS in the Apple App Store. This tool lets you pick the codec you will be using, and it tells you how much bandwidth a single track of that codec needs in bytes per second.
Once you know how much bandwidth a single track of the codec requires, your next step is to determine how many tracks you are going to need to play back at once. If you will only be doing simple editing with some transitions and text overlays, then twice the bandwidth is probably enough. However, if you plan on doing multi-camera cutting in real time, or using a large number of layers simultaneously, you are going to need far more. Below are a few popular codecs, as well as the amounts of bandwidth they require:
- AVCHD 1080p at 30 fps – 3MB/s
- XDCAM EX 1080p at 30 fps – 4.5MB/s,
- ProRes 422 1080p at 30 fps – 21MB/s
- ProRes HQ 4K at 24 fps – 106MB/s
Single 3.5″ drives
If you will be editing HD content without a huge number of tracks, then a high-performance 3.5″ drive will probably be fast enough to meet your needs. Current high-end 7200 rpm 3.5″ drives are able to reliably deliver speeds at 150MB/s or higher, in capacities as high as 4TB, which is enough to play back numerous tracks of lightly compressed video, such as DnxHD or ProRes. Some recommended 3.5″ drives are the 4TB Western Digital Caviar Black, the 3TB Seagate Barracuda, or the 4TB Hitachi Deskstar. All of these drives should give you at least 150MB/s of sustained transfer speed for video editing.
|4TB Western Digital Caviar Black
||3TB Seagate Barracuda
||4TB Hitachi Deskstar
Lower-performance 3.5″ drives (or 2.5″ drives) are not recommended for video editing, even if their published speeds are fast enough. These kinds of drives are often not designed to sustain those speeds.
If 150MB/s isn’t enough, and you still prefer using a single drive, the WD VelociRaptor is a good choice. It is a 10,000 rpm 2.5″ drive on a large heat sink designed to fit into 3.5″ drive bays. While the capacity isn’t as high as full-size 3.5″ drives (it maxes out at 1TB), it’s still larger than most SSD drives and can reliably deliver speeds of around 200MB/s.
SSD drives have a reputation for being much faster than hard-disk drives. Aside from speed, their main advantage is their near-instantaneous seek times, as well as their ability to read many small files at nearly the same speed as one large file. This is excellent for storing operating systems and programs, as they often require accessing large numbers of small files. However, for video editing, what you really need is a sustained transfer rate, and while SSDs are still faster than hard drives for this, it’s not by as much you may have thought. A high-end SSD will give you around 400MB/s sustained transfer speed, though at a vastly higher price per GB than a hard-disk drive. If money is no object, or if you don’t need that much storage space, then SSDs are great. Otherwise, if you need more speed than a single hard drive can deliver at a more reasonable price per GB, then RAID drives can be a great fit.
If you don’t have space in your computer for internal drives, then you will need to use an external drive. External-drive performance is determined by two factors. First, the actual speed of the drive being used is important. The best external single-drive setups use high-performance 7200 rpm drives, like the ones discussed earlier. If a manufacturer does not publish the speed of the internal drive that’s used, it’s probably because it’s not very fast.
The second factor that determines the performance of an external drive is the speed of the interface used to connect it to the computer. Sometimes external-drive manufacturers will advertise the speed of a drive’s interface as if it were the speed of the drive itself, which is not the case. Also, interface speeds are usually listed in bits per second (remember: there are eight bits in one byte). The interface primarily determines the maximum possible speed at which a drive could work. If a drive is faster than an interface, there will be no benefit, so it’s a good idea to have an interface that’s much faster than the drive. Below is a list of different interfaces and what their maximum speeds are.
USB 2.0: This is an old interface whose theoretical maximum transfer rate is 480Mb/s, or 60MB/s. However, actual performance of USB 2.0 is often far lower than its theoretical maximum. This interface should not be used for video editing, since it can barely play back a single track of HD ProRes HQ.
Firewire 800: This is another older interface, though still a good deal faster than USB 2.0. Firewire 800 has a maximum transfer rate of 800Mb/s, or 100MB/s. While it’s fast enough for simple edits, Firewire 800 is not recommended, as it is still slower than the speeds of which most hard drives are capable.
eSATA: This is essentially an external SATA II connector, and has a maximum transfer rate of 3Gb/s, or 375MB/s. eSATA is able to reliably transfer data at that speed, though it does not support daisy-chaining, work with hubs, or support bus power. It is a good option for single external drives or two-drive RAID 0.
USB 3.0: This interface replaced USB 2.0 and is far, far faster. The theoretical maximum transfer rate of USB 3.0 is 4.8Gb/s, or 600MB/s. However, to achieve the 4.8Gb/s speed, both the computer and drive must support the USB attached SCSI (UAS) mode. If either device is not using that mode, the performance of USB 3.0 is about the same as eSATA, which is still fast enough for a high-speed single drive, or a dual-drive RAID 0.
“… if you are using RAID arrays or SSD drives externally, Thunderbolt is the best interface.”
Thunderbolt: This is one of the fastest interfaces currently available. Thunderbolt 1 works at up to 10Gb/s, or 1250MB/s, while Thunderbolt 2 supports an even higher speed of 20Gb/s, or 2500MB/s. These astronomical speeds are far higher than those of any single drive. Since Thunderbolt drives are typically more expensive than their USB 3.0 or eSATA equivalents, it may not be worth the price increase, since you won’t see any higher performance. However, if you are using RAID arrays or SSD drives externally, Thunderbolt is the best interface.
If a single drive isn’t fast enough, and you need more storage than an SSD drive can offer, then you need to set up a RAID array. RAID arrays use multiple drives together to increase speed, protect your data, or both. You can configure your own RAID array via software or, for best performance, use a hardware RAID controller or external RAID array with its own controller. When building a RAID, all of the drives must be the same size and, for best performance, should also be the same speed. If possible, use the same model of drive as well. Below is a list of popular RAID configurations:
RAID 0: Raid 0 is all about speed. A RAID 0 stripes all the drives in the RAID together and is able to achieve nearly the same speed as the number of drives that are combined. For example, four 4TB 3.5″ drives that read and write at 150MB/s would create a 16TB RAID 0 that reads and writes at nearly 600MB/s. Another advantage of RAID 0 is that it works with as few as two drives, so the cost of entry is lower than that of a more complex RAID. The downside of RAID 0 is that there is no data redundancy, so if one drive fails, you lose all of the data on the entire RAID. So, the more drives you have in RAID 0, the more likely you are to lose all of your data. RAID 0 configurations make for great scratch drives, as long as you back them up.
There are a number of preconfigured RAID 0 drives available from different manufacturers. G-Technologies 8TB Thunderbolt G-RAID comprises two 4TB 3.5″ drives preconfigured as a RAID 0, which is why it offers transfer rates of more than 300MB/s. Lacie’s 2big series of drives, which are available in both Thunderbolt and USB 3.0 versions, are also configured as RAID 0 and offer more than 300MB/s transfer rates. Western Digital also offers the MyBook VelociRaptor Duo, a preconfigured RAID 0 with two 10,000 rpm drives and a Thunderbolt interface, which should offer speeds close to 400MB/s. It’s also possible to set up a RAID 0 with multiple internal drives in your computer, or make your own with an empty two-bay drive enclosure.
|8TB Thunderbolt G-RAID
||Lacie 2big series
||MyBook VelociRaptor Duo
RAID 1: Raid 1 is all about data redundancy. It uses two drives and completely mirrors them, so if one fails you have an exact copy. A RAID 1 will be no faster than a single drive, but it’s the only option for complete redundancy with two drives. This is not the best option for video editing, unless you don’t need speed.
RAID 5: RAID 5 is a popular option for video editors. It offers much greater speeds than a single drive (though not quite as fast as a RAID 0), with protection against drive failures. In a RAID 5, one drive can fail without any loss of data. The main disadvantage of RAID 5 is that at least 4 drives are required to make one, so it has a higher cost of entry than RAID 0. A RAID 5 made of four 4TB 3.5″ drives that read and write at 150MB/s would create a 12TB RAID 5 that reads and writes much faster than 150MB/s. Since RAID 5 requires more processing power than a RAID 0, the maximum speed will vary, depending on how good the RAID controller is, so it’s worth checking the individual published speed.
Promise Technology offers a number of preconfigured RAID 5 arrays of varying capacities in both Thunderbolt 1 and 2. The 4-Bay Pegasus versions are capable of more than 500MB/s in RAID 5, while the 6-Bay versions are advertised as being able to reach 800MB/s, fast enough for almost any task. Since even 800MB/s is slower than Thunderbolt 1, there will be no difference in speed between the two versions. However, if you’re daisy-chaining multiple devices, Thunderbolt 2 versions will work better.
For those without Thunderbolt, who want to benefit from the high speeds of a 4-Bay RAID, G-Technology also offers the G-Speed ES Pro line that utilizes PCIe-based RAID controllers and either mini-SAS or multiple eSATA interfaces to maximize performance, such as the 12TB G-SPEED eS and 16TB G-SPEED eS. Keep in mind that a computer with a free PCIe slot is required for these solutions.
Beyond RAID and other types of RAID arrays
Some companies, such as Drobo, are offering more flexible types of RAID arrays that can work with drives of different sizes, and allow you to add drives at any time. While convenient, they are heavily reliant on software, and are nowhere near as fast as a standard RAID array. If you’re looking into RAID drives for their speed advantages, these are not the best option.
“If you want to be able to use a networked RAID array as a scratch drive on multiple computers simultaneously, then setting up a SAN network is the best way to go.”
Networked Drives: Sharing editing projects between multiple computers can be a huge hassle. Carrying around external drives from computer to computer is both time consuming and cumbersome. Plus, RAID arrays are far from portable. Some RAID arrays are so fast that they could handle multiple users with ease… if only there were a way to share the same drive on multiple computers. Well there is, though it varies in difficulty to set up, as well as usefulness.
NAS Drives: NAS drives share their storage over a TCP/IP network. They’re easy to set up, and if used on fast Gigabit or 10Gb/s Ethernet networks, they can be fast enough to stream multiple high-bandwidth video tracks simultaneously. However, because of the way TCP/IP network protocols work, they are not recommended for use as scratch drives, since most editing software has trouble utilizing them. However, they can be great for backing up files in a safe way, or sharing and storing video files and projects in a safe location, since NAS drives can be configured as RAID arrays with data redundancy.
SAN Drives: If you want to be able to use a networked RAID array as a scratch drive on multiple computers simultaneously, then setting up a SAN network is the best way to go. SAN drives show up as local storage to connected computers. However, SAN drives use a different file system than standard drives, so software such as XSAN or ATTO Xtend SAN must be installed on each host computer. SAN networks typically interface with fibre channel connections, so each computer also must have a fibre channel host adapter, such as an ATTO Technology Celerity card, to interface with the SAN network. For Apple computers, such as the new Mac Pro, which lack PCIe slots for fibre channel cards, Promise Technology offers the SANLink2, which adapts a Thunderbolt 2 connection into dual 8Gb/s fibre channels for hooking up to a SAN network. Also, to direct all the fibre traffic between the workstations and the RAID array, a fibre switch, such as the Q-Logic’s SANbox, is required. An additional computer not being used as an editing system is required to run as a dedicated metadata server for the SAN network.
Example of a basic Fibre Channel SAN Network Setup
Needless to say, setting up a SAN network is not for the faint of heart; however, when done, it can greatly speed up workflow, while providing data redundancy for small businesses with multiple editing computers. Some advanced non-linear editing software, such as Avid, allows for multiple editors to work on the same project simultaneously on a SAN network.
SAN-compatible RAID arrays are available from a number of manufacturers in numerous configurations. One popular line of rack-mountable arrays that can be used to make a SAN network is the Sonnet Fusion RX1600Fibre, or the Promise Technology VTrak fibre array. Both of these units offer speeds more than 1,000MB/s, enough for several users to work simultaneously.
|Sonnet Fusion RX1600Fibre