New PowerEdge T20 build, need advice on how to setup hard drives.

[hezohab]

Hi,

I am doing my first Freenas build. This NAS will be backing up important files, thus my goal is reliability and safety.
Speed or throughput are not a concern for me as it will be only be used by me and I won't be doing any intensive tasks.

I have a Dell PowerEdge T20 and I have ordered 32 GB (max for this box) of ECC ram.

Next, I would like to understand how best to setup my hard drives.
I don't know what size and what configuration (raidz1 vs raidz2) would be optimal.
I bought an expansion card that will allow to me to put 2 extra SATA drives for a total of 6 3.5 inch drives.
I don't have a specific amount of usable hard drive space that I need, but I would like to max out this box to make it as future proof as possible.

If I stick to the 1gb/tb rule, I have been thinking about these setups:

• 4x8TB in a raidz1
• 4x8TB in a raidz2
• 5x6TB in a raidz2

Any thoughts or advice would be greatly appreciated.

Thanks

 

[gpsguy]

it's 2019, forget anything to do with RAIDz1. It's too risksy with large capacity hard disks.

Please provide detailed hardware information regarding your SATA expansion card. Many aren't suitable for FreeNAS.

 

[hezohab]

Sure,

The expansion card is a Startech 2 port 6gbps, part # PEXSAT32.
I bought it from Dell when I was purchasing the T20.

So you recommend a raidz2 setup, should I go with 4x8 or 5x6?

Thanks

 

[pschatz100]

How much capacity do you want? With 4x8TB drives in a RaidZ2 configuration, you will have 16TB of raw capacity yielding about 12TB of usable storage, and two disks of redundancy. This is a very reasonable configuration.

Why do you think a 5x6TB configuration might be preferable?

 

[pab49162]

I have been running FreeNAS on a Dell PowerEdge T20 for about 3 years and it is a good little box for this. Right now, I am using four 3 TB drives in a raidz2 configuration and have 20 GB of ECC RAM.

While I don't plan to add more storage right now, it is something I have looking into in the past. Here is an old posting from 2018 where I got some excellent information from other people on this forum.

As far as potential issues you may encounter, you already understand that you need an expansion card for more than 4 drives. Two other things that I came across when looking into this were additional cooling and physical mounting of more than 4 drives.

From other posts I have read, additional cooling is probably a really good idea if you decide to use more than 4 drives to the T20 box. Just wondering it you have given any thought to this and if so, what options are you considering.

As far as physically mounting more than 4 drives, I have seen several postings about potential solutions. If you haven't seen this posting before, you may find it to be informative.

Hope this helps.

 

[hezohab]

How much capacity do you want? With 4x8TB drives in a RaidZ2 configuration, you will have 16TB of raw capacity yielding about 12TB of usable storage, and two disks of redundancy. This is a very reasonable configuration.

Why do you think a 5x6TB configuration might be preferable?

As you mentioned 4x8TB would give me 16TB of raw capacity. The reason I am considering a 5x6TB option is that it would yield 18TB of raw capacity. At least that is my understanding, I am new to this.

Thanks!

 

[anmnz]

If I stick to the 1gb/tb rule,

Don't. It is outdated.(*) For straightforward file-sharing duty, 32GB RAM will almost certainly be sufficient for as much disk as you can fit in that box.

(*) I don't mean that it was a bad rule in the past, just that it doesn't really scale up as-is beyond 8TB of disk, and these days it is irrelevant below 8TB due to the stated 8 GB RAM minimum requirement for FreeNAS.

 

[Stux]

as Mentioned, avoid RaidZ1. Go with RaidZ2.

And if going with RaidZ2, 6-way is a good minimum. With 4-way you’re only seeing 50% storage efficiency, With 6-way you’re getting 2/3rds (66%).

So, if you can use 6 disks, do, and get the biggest disks you can budget for.

Alternatively, just use mirrors and start with a pair of big disks.

 

[pschatz100]

as Mentioned, avoid RaidZ1. Go with RaidZ2.

And if going with RaidZ2, 6-way is a good minimum. With 4-way you’re only seeing 50% storage efficiency, With 6-way you’re getting 2/3rds (66%).

So, if you can use 6 disks, do, and get the biggest disks you can budget for.

Alternatively, just use mirrors and start with a pair of big disks.

I think a Dell T20 has space for four 3.5in drives (correct me if I am wrong) and there are four SATA ports on the motherboard. To go to six disks will require modifications to the case and some sort of SATA expansion.

While I agree that a 6 disk Raidz2 would give a bit more bang for the buck in terms of storage, the OP said his priorities were reliability and safety. There is nothing wrong with 4x8TB drives in RaidZ2 as long as it provides adequate capacity. I would consider 4 disk Raidz2 to be more reliable than two mirrors because any two drives can fail without losing the pool.