black and gray computer motherboard

RAID: What is it, how does it work, and what do I choose for my server?

In this article, we will talk about the best roach killer for your studio and how it works. RAID Ant and Roach killer’s active ingredients contain a potent blend of tetramethrin, prallethrin, and permethrin to act as a sort of “nerve gas” for insects.

Just kidding, although I’m sure the workings of roach killer may fascinate some, this is a Post-Production blog… not a Home & Garden blog.

RAID 0 ,1, 5, 6, 10. What are these numbers, what do they mean, and which one do I choose for my post-production machines?

Okay before I begin, RAID is extremely technical. I could write for hours regarding the inner workings of RAID and the small technicalities that separate each flavor. But, as this is a post-production blog, I will be focusing on the broader aspects of RAID and how they relate to post-production in the simplest yet most complete way possible. Let’s dive in.


Image Courtesy of Seagate
Image Courtesy of Seagate

Do you want speed? Well, look no further. RAID 0 was created to have the fastest drive speed possible with absolutely zero regard for data security. If you like to live on the edge and don’t care about losing data, then RAID 0 is for you.

RAID 0 is great for raw speed and combining 2 smaller drives into 1 larger drive. This is perfect if you want 2 TB of solid-state storage but only have two 1 TB SSDs (2 TB SSDs are expensive!!!). Not only will your cheap 1 TB SSDs be turned into a single 2 TB SSD but your read/write speed will double. But there are downsides…

Look at the graphic, and notice how a single “file” is spread across 5 drives. For example, if you store a 5 MB file on a RAID 0 array, that 5 MB file will be cut up into five 1 Mb “chunks” and spread across all 5 drives evenly. If one drive fails, you lose that file (as well as any others) completely. There are ZERO ways to restore that data or rebuild that array. That data is gone. 

Are you swearing off RAID 0 then? Yes? Well… not so fast. There are indeed benefits to RAID 0. I use RAID 0 in my PC as an Adobe Premier cache drive. I locate all my caches on that drive and additionally use it to temporarily hold high-bitrate/high-resolution video files (8k footage for example). I also store other random things on that array… but I always make sure that whatever I put on that drive I have a backup of or don’t care to lose.


Image Courtesy of Seagate
Image Courtesy of Seagate

If RAID 0 is the “hare” then RAID 1 is the “tortoise.” Yet… slow and steady doesn’t always win the race. In the post-production world, RAID 1 only has a single use: to protect your data. You don’t get any performance boost and your total capacity is cut in half. Combining two 1 TB drives will give you (drum roll…..) 1 TB. And your speed… well, that will be the speed of a single drive. No RAID speed boost magic to be found here. The only time I have ever used RAID 1 is on the SSD cache in your server. That is also the only time I can foresee anyone using it too for post-production. There are just better flavors of RAID out there.

Take a look at the graph. It’s very simple. Think of RAID 1 as an expensive real-time backup solution.


Image Courtesy of Seagate
Image Courtesy of Seagate

When it comes to picking a RAID flavor for your server, the most common question is “RAID 5 or RAID 6.” And the answer is… it depends. RAID 5 is great as it allows for a single drive failure and provides a noticeable speed boost like RAID 0. On average your read speed will be hovering around 320 MB/s and your write will be around 210 MB/s. These numbers will fluctuate depending on several factors but if you are planning on building one of the servers I have in my blog… then these performance numbers won’t be far off (keep note that if you have an SSD cache, your transfer speed will be much higher until the cache is filled). 

RAID 5 works by stripping data across a minimum of three drives and creating “parity information” on each drive. As I mentioned in the intro, RAID is extremely technical and requires a lot of math and a degree in computer science to fully understand. Just think of parity as an unsolved equation in which the RAID controller can calculate using the data from the remaining drives if one fails. 

So RAID 5 sounds great then?! You get data redundancy and speed boosts. Well… not so fast. RAID 5 can only support a single drive failure. If two drives fail then your data is gone. Okay, but the odds of a second drive failure are pretty low, right? Well yes, it is “low” but not something to disregard. 

When a drive fails, the RAID controller has to rebuild the failed drive on the replacement drive. When this happens, your drives are working hard, therefore, adding a decent amount of strain to your system. If there is another drive in your system that is also close to failure, then there is a good chance that it will fail during the rebuild. Bye-bye data. 

The only time I recommend RAID 5 is if it is being backed up off-site and your RAID array is mostly being used for cold/secondary storage. Yes, you can use it for your hot storage and you might never have a problem but I don’t recommend it. If you do decide to go with RAID 5 then make sure you have a hot spare (more on that later).

Image Courtesy of Seagate
Image Courtesy of Seagate


This is it. This is the flavor of RAID that I recommend for most, if not all, post-production servers. RAID 6 is very similar to RAID 5 but it differs in that it needs a minimum of four drives so that it can create double-parity. Double-parity means that a RAID 6 array can handle 2 two simultaneous drive failures.

Regarding speed, a RAID 6 array has the same read speed as a RAID 5 array but a slower write speed (210 MB/s vs 180 MB/s). This is not an issue at all for editing as you have an SSD cache drive to make up for that loss in performance. But for multi-terabyte file transfers… this will slow things down (but not by much).

By having almost all the performance gains of RAID 5 but with the added security of double-parity, this is the clear choice for your brand new server.

Image Courtesy of Seagate
Image Courtesy of Seagate


Seriously? Another RAID flavor? Yeah, but I’ll keep this short. RAID 10 is RAID 0 mixed with RAID 1. You will probably never use it as it’s extremely expensive and overkill for anything other than an enterprise data center. You get all the raw speed of RAID 0 while also having your data mirrored onto an identical pair as shown in the graphic. If you want a 4 TB raid you would need a total of 8 TB of drives.

Anyway, that’s all the time I’m willing to write about RAID 10. It’s not bad but it’s just a waste of money for a post-production studio.

Image Courtesy of Seagate
Image Courtesy of Seagate

Hot Spares

Hot spares are easy. It is just an empty hard drive that will instantly start synchronizing once the RAID system detects a disk failure. No need to power down the raid to replace a drive, the RAID controller does it automatically. I recommend adding these to systems that have 8 bays or larger. The more hard drives in an array, the statistically higher chance you have of one of those drives failing. Therefore, it is wise to add 1 hot spare for every 8-12 hard drives.

In Conclusion

I hope this wasn’t information overload. I know RAID and data systems are difficult to understand but so long as you know the basics you are golden.

Go with RAID 0 if you don’t care about losing data.

Go with RAID 1 for server cache.

Go with RAID 5 for cold storage or hot (but only if you have a backup)

Go with RAID 6 for almost all server builds.

Go with RAID 10 if your pockets are overflowing with cash.

And make sure to add a hot spare if you want that extra security, peace of mind, and can’t afford any downtime.

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