NAS Guide

During Team PGP stream the other day Wendell suggested someone in the chat should post a guide on their NAS build......Anyone, anyone, Bueller? Bueller? 😁

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What do you want to know ?


Well, I was looking at synology maybe, and then I heard wendell say "you should post that as a project, I hear people say should I spend 800 on this nas and I think Noooooooooo!" 😁 So, thinking this through....i know I need say 2 NAS HDs, one to back up the other, I don't need RAID for that, I need a case to put them in and.... Well, that's pretty much the extent of my knowledge tbh! So, without going for an off the shelf product, I still need a cpu, software, network hardware.

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It was posted here:


Cool! I wish I could like this twice :-)

What kind of budget do you have ?

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Pretty small, but not so low as to fall into the buy cheap pay twice bracket. So the hard disks need to be decent, I was thinking 2 x 8tb NAS disks, one to back up the other. The 8tb will be for documents and photos plus music and film to stream. I think they'll be the biggest expense and the rest need to fit around that.

Those drives aren't cheap so what's small?

Hey that was my NAS, if you are talking last week. I threw this "guide" together as fast as possible, and it was my first post on the forum... it isn't great on guidance and may not even be in the correct place. Thanks to @Thinking_Emoji for finding it for you.

As I said in my original post, I'm happy to answer questions or flesh out the guide a little more, if desired.

Edited: because... grammar...

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Well that's the rub. The cost of the drives alone with that much capacity is fixed. It is what it is and leaves me thinking I need to explore what savings can be made elsewhere.

Maybe don't go for 8tb drives? Do you need 8tb with backup right now? What about (4) 3tb drives in a RAID config? Using ZFS, you'd get roughly the same useable space with drive failure protection at 50% of the cost assuming $90/3tb drive vs a $350/8tb solution. Not to mention... 8tb is a lot to lose at once when things go very wrong. I'm not personally convinced of the usefulness of very large storage drives, yet.

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That's helpful thanks. Looking again at those large drive prices I'm gonna have to lower expectations. I've heard not good things about raid though, is it safer to match every drive with its own backup?

I have to agree with @OMGitsManBearPig. Especially when you have big drives, a failure will take quite some time to recover, when you replace the HDD. Wendell even talked about this on one of their shows. The thing is, drives are getting bigger and bigger but their transfer rates aren't keeping up, so the issue is getting worse.

Also the problem is that in case of a failure the drive has to not only carry the current load but also the additional load of resilvering (the process of writing to the replacement HDD). That additional load, which is more if your drives are bigger, might easily trigger another drive to fail.

More details related to RAID-Z

This is why the people at FreeNAS don't recommend RAID-Z1 anymore and tell you to go with RAID-Z2 instead, since the latter can run with two drives failing, instead of just one. If you have really critical data, you might even want to go as far as to use RAID-Z3 which can run with three failed drives, however you will need a higher total number of drives as well. ;-)

Also another important thing to consider when you are buying HDDs for your NAS is that you are buying the drives from different batches. This way the drives don't share a similar production and transportation history and they aren't likely to fail at the same time. Some people even buy from different manufacturers, which shouldn't be a problem if they share the same basic specs like capacity, cache size, RPM, etc.

If you are going with FreeNAS, which I would highly recommend, since it is powered by ZFS, you have a few options. You can either mirror each drive, which delivers the best performance and fastest resilvering, but also is the worst deal price to storage wise.

Another option is using RAID-Z, which is a special type of software RAID, that's part of ZFS. As I mentioned before, you can have different levels of redundancy, where the number after the "Z" tells you how many drives can fail before your data is lost.

RAID-Z & the number of drives

It is also recommended to use a power of two number of drives (2,4,8,16,etc.) plus 1,2,3 drives for redundancy. So if you need 5 TB of storage, you can go for 2x 4TB or 4x 2TB drives plus one or two additional drives for redundancy. In my home FreeNAS box, I have 3x 2TB drives, where one drive is for redundancy and the other two are for actual storage. I got mine already "pre-mixed" in production dates, so that should be fine too. ;-)

As you can see, with RAID-Z you get a much better deal since you only need one or two more drives for redundancy, instead of having to mirror each drive separately.

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You have to think carefully about the OS.

FreeNAS for example needs a decent commitment to the system specs. Namely a reasonably powerful CPU and and good amount of RAM. You also need to scale the amount of system memory with the storage size and ECC is a big consideration.

Synology on the other hand will run on just about anything but it's nothing like as flexible.


But Pete. Now my mind is full of ghost busters quotes 😂

"they gave us money and facilities. You don't know what it's like, you've never had to work in the private sector..... They expect results"

This is also helpful by the way, thanks, joking aside. Now I'm thinking Synology again. And with zero Linux experience maybe a nas to store my family photos isn't the best first project..

I would never have factored this in. Wouldn't have crossed my mind. Thank you! ☺ 👍

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I totally agree with RAM, I have 8 GB installed right now for my 4+2TB of storage and I feel like it could use more, since it can easily saturate it and when I am doing some heavy tasks inside a jail, it quickly starts swapping. Another pair of 8GB is therefore on my student's wishlist ;-)
As a side note to @FIVEam, in case he/she is (still) considering to build a FreeNAS box, the rule of thumb is to use at least 1GB of RAM for 1TB of storage. There is nothing better than more RAM when it comes to ZFS, except for even more RAM :'D

In my opinion the CPU isn't a super critical issue. I have a Xeon E3-1220 v5 which is comparable to a Core i5-6500 performance-wise and it's almost always near idling, even when there are two jails working in the background and I am transferring a lot of small files. I have never seen it go higher than 50%, even during update installation.
However, I never had to resilver a drive so far, so I can't tell how the load would be when the system has to calculate parity for the new drive. But then again, I only have three drives, so I feel like the two drives would restrict the speed of the process more than the CPU.
If @Dr.Venkman or someone else has some real-life experience on CPU load during resilvering, I'd be glad to know :D

Let me get that for you :D

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