Unraid on an R710 Part 2: Hardware

To avoid rambling on forever, I'm going to assume that you are interested in or you have an R710, and you at least have a basic understanding of normal computer hardware and components. There are a few tricks to getting an R710 ready to host and Unraid server. The point of this blog in general is to collect, organize, and present all the knowledge I've gained while setting it up for myself. So, this post will serve as a quick crash course in getting an R710 configured to run Unraid, and the stuff I learned while doing that.

Finding the right R710

There are a ton of sites where you can buy refurbished R710s. You can even get them on Amazon. I got mine off Ebay, and I bought additional memory for it later (see here and here for more info on memory spec and configuration).

R710s come in two primary configurations. Mine has 8x2.5" hard drive bays, or you can get one with 6x3.5" hard drive bays instead. "Normal" desktop PC hard drives are 3.5" - the one that are 2.5" were mainly used in older servers and laptops before SSDs became ubiquitous. Both R710 options are rackmounted (R710, as opposed to the T710 tower), 2u or 2 rack units high. You don't need a rack, my server is sitting on a table in a closet ? but if you want to mount your R710 in a rack, you will obviously need rack rails at the very least.

I won't go through the whole spec sheet but they have two Xeon 5500/5600 CPU sockets and a 18 DDR3 RAM slots as well. Compatible CPUs are cheap, too.

R710s also come with some other stuff. Like a RAID controller. A RAID controller manages your hard drive configuration and connects them to the server. Mine came with a PERC 6/i  but the most commonly found alternatives are the PERC H200 or PERC H700. Your server should also come with an IDRAC6 Enterprise remote controller module. All of that will be relevant later in this series.

Picking Hard Drives for Unraid

There are more detailed instructions on the Unraid wiki, but I'll go over my particular configuration. When buying your initial set of drives, remember that Unraid isn't free outside the free 30 day trial and costs money based on how many drives you want to attach.

With the 8x2.5" bay configuration I have, I believe you can fit any 2.5" HDD or SSD in any bay. SAS HDDs are generally faster than regular HDDs, will generally have a longer lifespan, but be more expensive and have a smaller capacity than your typical consumer HDD. Also notable, SAS drives don't spin down normally as of Unraid 6.9.2 - there's a plugin to make them spin down but it doesn't seem to work for me. Some manufactures make non-SAS drives that are aimed at NAS usage (like the Western Digital Red 3.5" drives) which would be appropriate too. I use a mixture - I have a normal 1TB 2.5" laptop drive, and some 300gb Dell and Seagate SAS HDDs, plus one Samsung 250GB 2.5" SSD.

R710s use drive caddies like this one on Amazon (2.5" version) to hold the drives. Instead of having cables that connect to each drive like your desktop PC, each drive bay backs up into what is called a backplane. This backplane board has power/data sockets for each of your drives. You just push your drive into the bay until it slides into the connector and you can close the latch on the caddy. The backplane is connected to your RAID controller (or HBA card) typically by Mini SAS cables. Those are specifically the ones I bought for my PERC H200 and R710.

The way I like to think about is there are three uses for drives in Unraid:

1. Storage Drives are the drives in your array that actually store your data. You want to use HDDs for these, and preferably SAS HDDs for optimal reliability/lifespan, but you can also use regular 2.5" HDDs to save money. SSDs are not recommended (Unraid lists them as "experimental" in its documentation) as they do not efficiently work with Unraid's method of handling parity.
2. Parity drives are the drives in your array that store parity archive data for your Unraid storage. These drives store some information that helps keep track of all of your data using math. You can have 0, 1, or 2 parity drives. They must all be at least as large as your largest storage drive. You can recover from 1 storage drive failure per parity drive.
3. Cache Drives are drives that are handled outside your array. Unraid is designed to write new data to the cache drive, and then automatically move it to the storage array later. This is because Unraid's storage array structure doesn't improve write speed like certain RAID configurations do, and constantly writing to your storage array will keep random - or even multiple - storage array drives spinning constantly (which will increase power consumption and reduce array drive lifespan).

Parity and Cache drives are optional, but I would suggest getting at least one of each for starters (don't worry, you can add more of any drive type later). Protecting your storage array with parity drives is generally good advice, since drives do occasionally fail. And due to how Unraid uses your cache drive/cache pool, I would absolutely suggest getting big-ass SSD(s) for your cache drive(s). You will see the biggest drive performance benefit that way. If you plan to use multiple cache drives, they can be set up as one big pool or as a redundant RAID-protected pool - watch this video for info on that (and also subscribe to his channel, he puts out a lot of helpful content).

RAID Controller

Normally these R710s include a RAID controller so that you can arrange and manage your hard drives in a RAID array. But Unraid manages the storage array with its software, instead of relying on a hardware controller device. This means your RAID card doesn't need to do a whole lot.

The most common (as far as I know) RAID controller for R710s is the PERC 6/i. For Unraid, you want your RAID controller to just present your drives to the software. The PERC 6/i can't do this, it can only present drives to the operating system software as its own virtualized drives. That means for our purposes, you will need to swap to an H200 or H700 (linked above) and then flash them - update the firmware - to allow them to operate in what is called IT mode. Or, you can buy them pre-flashed all over the place (I got mine pre-flashed from Amazon).

Unfortunately I'm writing this from memory and I did my RAID card swap a few years ago, so I don't have detailed instructions/pictures/video for doing it. There are many guides and videos out there for it. I suggest a PERC H200, mine works flawlessly.

Other Hardware

R710s come with a four-port Network Interface Card (NIC). Dell also provided you with PCIe slots for expansion - some older graphics cards even fit in those slots, but I believe they force the server to run fans at a higher speed, causing a lot of noise. Also there are a few flavors of IDRAC6 System Management Interface - I have the enterprise level one with it's own dedicated ethernet port. You shouldn't have to do anything special to those to get Unraid working, but I would recommend an IDRAC6 Enterprise card at least. They are pretty cheap on ebay/amazon and really easy to install, and should come in handy when you need to update or manage your system remotely before booting into the OS. More on that in the next few posts in this series.

Additionally, if you have a spare VGA-capable monitor and USB keyboard, plugging them in may help with initial setup of your server. They aren't necessary, and I'll go over why not in my next post, but they're a good workaround for a properly-configured IDRAC6 module.

What's next?

I think your next steps should be:

1. Update and configure the various firmware that manages your server's hardware
2. Set up your Unraid USB
3. Configure your BIOS
4. Get Unraid running

Thanks for reading! Contact me or comment below if you have any questions or comments.