snapraid 1PB of drivepool with snapraid

[celiswen]

I saw many post are talking about 3-6 drives, but i can't find a post that are talking about 100 10TB drives.

I am trying to crate a 1PB drive in drive pool, is that mean I need an other 1PB drive pool for parity, or I set 100 drives as data drive at snap raid? If i set 100 drives as data drive at snap raid do i need a 1PB drive too or how big should the parity drive size be.

Is there anyway to do software raid 5?(not windows raid5)

[saitoh183]

You can put as much parity as you want it depends on your level of comfort with fault tolerance. If you use 1 parity drive, then you are safe against 1 failure. If 2 drive die at the same time,well your screwed. Your parity drive has to always be as large as large or larger than the biggest drive in your pool. But at the end of the day the number of parity you put comes down to how paranoid you are about protection

[Christopher (Drashna)]

Well, StableBit DrivePool can use 100x drives, without any issues.  

As for snapRAID, I'm not too familiar with it, but you may want to take a look at this link: 
http://www.snapraid.it/faq.html#howmanypar

basically, more == better, but they've only had reports of 4 disks failing at a time.  So, you may be able to get away with 5-6 disks for parity. 

But again, I'm not too familiar with it. 

[celiswen]

Thx, i will use 6 parity drive for my setup.

Do snapraid keep their parity file as a single large file? Or there will be more files when size grow.

[Christopher (Drashna)]

I believe that it doesn't grow.  The main limit is that the drive needs to be as large as the largest disk it's protecting, IIRC

[Chris Downs]

On 7/10/2020 at 1:36 AM, Christopher (Drashna) said:

Well, StableBit DrivePool can use 100x drives, without any issues.  

As for snapRAID, I'm not too familiar with it, but you may want to take a look at this link: 
http://www.snapraid.it/faq.html#howmanypar

basically, more == better, but they've only had reports of 4 disks failing at a time.  So, you may be able to get away with 5-6 disks for parity. 

But again, I'm not too familiar with it. 

As a general rule, I use the following:

Consumer disks (including NAS WD RED and SG Ironwolf, but not the "Pro" versions) - assume a 10% failure in the first 3-5 years of their life. This % will increase over time of course. So for 100 disks, I'd go for 10 parity if I was doing it, and using consumer-grade disks.

Pro/Enterprise, you could likely get away with 5% failure rate assumption in the same time - obviously assuming you stay under the yearly workload specs. So the suggestion of 5-6 disks is pretty spot on if these disks are in use.