Hello everyone, planning my second unraid server build. The first is finally stable and will be passed down to my father, so that he can enjoy the awesomeness that is this OS. I will be lurking on here and probably asking too many questions about syncing the two servers, so that we have off-site redundancy, but i digress.

 

I am trying to figure out the best configuration for my new array. I will be utilizing 5 4 tb drives and 1 10tb drive. 

 

Now, I had been planning on just running two 4tb drives as parity and purchasing a couple other 4 tb drives for the array, but i was given a new 10tb drive which I'm hoping to make use of. 

 

Would it be better to run the single 10tb drive, and then look towards upgrading to a second 10tb parity drive down the line?

Or would it be better to run 2 4tb drives in parity and run the 10tb in the array?

 

I'd prefer not to purchase another 10tb drive for a while, as I don't think i will need more storage for some time, and this server is already taking out the large majority of my tax refund as is.

 

Any thoughts would be very appreciated, and thank you to LimeTech for such a great OS. Hope I can become a contributing member of this awesome community.

 

-Art

Parity drive must be equal to or larger than your largest data drive.

56 minutes ago, Art4security said:

Would it be better to run the single 10tb drive, and then look towards upgrading to a second 10tb parity drive down the line?

Or would it be better to run 2 4tb drives in parity and run the 10tb in the array?

You only have one option. Each parity must be as large or larger than any single data drive. So, the 10TB must be parity. You can then run any number of data drives up to your license limit each being 10TB or smaller. After you get past 10 or so data drives I'd recommend 2 parity drives, but if you keep a close eye on the health of your drives and run monthly parity checks to weed out bad drives at the first sign of trouble, the second parity is not needed 99% of the time.

Perfect, thank you guys! The new build will start next week. The old xeon e5 with ddr3 was fun, but im looking forward to this threadripper 2 build and the possibilities all those threads will bring!

As an extension to Art's questions; How is it best to expand parity drive size?

Currently I have a 6TB as Parity and a 4TB HDD as Parity 2.

 

- Do I understand correctly that those 2 TB extra of the first parity-disk are useless/never written to because the second is only 4 TB?

 

- I intend to buy a 12TB disk which I'd like to make the new parity disk. How do I best do this, if I want to have the data-disk size limit (in the array) expanded to those 12 Tb ? Do I need to keep that 12 TB as the only parity disk then? If so, is there a way to make the parity redundant up to that 6 TB disk by just copying its content?

 

- In light of that new 12TB, are there any limitations within the Unraid Slackware OS regarding 4Knative or 512e access to the drives? I.e. should I get the 4kn or the 512e version of the 12 TB I'm planning on buying?

 

- I have the Dynamix File Integrity plugin installed making BLAKE2 hashes of all files, it does this quite fast. I was wondering, can't those hashes be implemented along with the parity-calculations? Or is that file integrity check not needed anymore with the way unraid handles parity?

Edited May 27, 20197 yr by fluisterben

11 hours ago, fluisterben said:

Do I understand correctly that those 2 TB extra of the first parity-disk are useless/never written to because the second is only 4 TB?

Correct

11 hours ago, fluisterben said:

if I want to have the data-disk size limit (in the array) expanded to those 12 Tb ? Do I need to keep that 12 TB as the only parity disk then?

Also correct. Or, you can purchase another 12TB to implement as parity2.

11 hours ago, fluisterben said:

is there a way to make the parity redundant up to that 6 TB disk by just copying its content?

You can't keep a 6TB parity disk and use a 12TB data disk. Parity 1 and parity 2 are different calculations, not just a copy from one to the other. Parity1 is simple to explain and understand, Parity2 not so much. Parity2 also requires more CPU power, but that seldom is noticeable unless you have an older CPU.

 

11 hours ago, fluisterben said:

In light of that new 12TB, are there any limitations within the Unraid Slackware OS regarding 4Knative of 512e access to the drives?

Not that I'm aware of. 4Kn support was added to unraid several versions ago, so the only consideration would be the reuse of drives in other applications after they graduate out the unraid array if wanted.

 

11 hours ago, fluisterben said:

- I have the Dynamix File Integrity plugin installed making BLAKE2 hashes of all files, it does this quite fast. I was wondering, can't those hashes be implemented along with the parity-calculations? Or is that file integrity check not needed anymore with the way unraid handles parity?

Unraid parity has nothing to do with files or file integrity. It only emulates the entire drive as a binary blob, any file system corruption is emulated along with the rest of the data. Any file integrity or checksum implementations would need to be handled separately.

7 hours ago, jonathanm said:

You can't keep a 6TB parity disk and use a 12TB data disk. Parity 1 and parity 2 are different calculations, not just a copy from one to the other. Parity1 is simple to explain and understand, Parity2 not so much. Parity2 also requires more CPU power, but that seldom is noticeable unless you have an older CPU.

 

As they are different calculations, can't at least one of them be smaller than the data blob? What I meant to ask is;

When I use only the 1 12TB disk for Parity, would it not make sense to use the 6TB as 'unassigned' disk, to backup part of that 12 TB parity? (So instead of using it as parity 2, use it to make parity 1 content at least half redundant..)

Quote

Do I understand correctly that those 2 TB extra of the first parity-disk are useless/never written to because the second is only 4 TB?

Correct

Strange; with the 6TB as parity 1 and the 4TB as parity 2 this now gives me a total of 7.3 TB, so that's not entirely true then, is it?

Edited May 27, 20197 yr by fluisterben