Recommended # of Parity Drives

[ang3l12]

So I am planning on building out my new server right now, and will have 5 1tb drives in it. Would 1 parity drive be fine with 4 data drives?

[trurl]

Yes, as long as you're diligent and careful.

 

The easiest way to be diligent is to setup Notifications so unRAID can notify you when there are problems.

 

By careful, I mostly mean checking your connections. Most problems are cause by bad disk connections.

[JonathanM]

6 minutes ago, ang3l12 said:

So I am planning on building out my new server right now, and will have 5 1tb drives in it. Would 1 parity drive be fine with 4 data drives?

Probably yes, but it's really up to your risk tolerance. How old are the drives? Have they been thoroughly tested? Unraid requires all remaining drives to be read perfectly to recreate failed drives, so having old sketchy drives is a bad idea.

[ang3l12]

11 minutes ago, jonathanm said:

Probably yes, but it's really up to your risk tolerance. How old are the drives? Have they been thoroughly tested? Unraid requires all remaining drives to be read perfectly to recreate failed drives, so having old sketchy drives is a bad idea.

 

They are new drives, server grade. I may pick another one up in a month or so then, I've reached my budget for this build for now

[JonathanM]

2 minutes ago, ang3l12 said:

They are new drives

New != good. Google bathtub curve. I recommend thoroughly testing them before trusting them with your data.

[tdallen]

"Most people" would have a minimum of 6 data drives before implementing dual parity.  It would be more common to see dual parity implemented at 8-15 data drives (or more).  As others have said, it depends on your risk tolerance, I'd say that implementing dual party with less than 6 data drives would place you in the "highly risk averse" category.

[trurl]

Why did you buy so many new 1TB drives? Fewer larger drives would have been cheaper, had the same or more capacity, would probably have been faster. And fewer drives means fewer opportunities for problems.

[Frank1940]

You can read here for more information about the probability of drive failures:

 

[Lev]

This topic caught my fascination lately due to a lot of great posts by many of you who already posted in this thread. Too many great posts to list that I've read, many that @Frank1940 has referenced. Rather than creating a new post, I'll just ask my question here....

 

If money is no object, and the CPU is not the bottleneck, is there any reason to not use dual parity?

 

I don't see any reasons, but I haven't read a single post where this is explicitly stated in clear terms.

[JonathanM]

5 hours ago, Lev said:

If money is no object, and the CPU is not the bottleneck, is there any reason to not use dual parity?

Nope. The only possible edge case I can see is if you are bumping against the single server drive limits and you would rather have the extra usable capacity instead of the redundancy. I only bring it up because I just read some of your other posts and could see that you use enterprise level equipment, and have a full rack.

 

Money no object, just spin up a whole nother server for full backup.

[Frank1940]

20 minutes ago, jonathanm said:

Money no object, just spin up a whole nother server for full backup.

 

And if you put that second server in a remote site, you will have eliminated another entire class of potential for loss of data-- the physical destruction of a server.

[Lev]

4 hours ago, jonathanm said:

Money no object, just spin up a whole nother server for full backup.

 

4 hours ago, Frank1940 said:

And if you put that second server in a remote site, you will have eliminated another entire class of potential for loss of data-- the physical destruction of a server

 

Thank you both. That is exactly what I'm working on with my old UnRaid server, now that my new UnRaid server has proven stable over the last month in operation. Once I've tested everything, it will be off-site, always powered on, with a  point-to-point VPN link to sync. Appreciate your validation of my plans.

 

 

[JonathanM]

2 minutes ago, Lev said:

I've tested everything, it will be off-site, always powered on, with a  point-to-point VPN link to sync. Appreciate your validation of my plans.

I'll just throw a small wrench in your plans. sync != backup. Backup implies versioning, and the ability to recover data that was erased or overwritten from the source. Make sure your backup server can give you back data that was overwritten or corrupted months ago without you noticing in the interim. I'm not saying keep everything forever, but at least be able to step back in increments. 1 day, 1 week, 1 month, 1 year. Or something like that.

[Lev]

Great advice, thank you! Sounds like I'll need to find a software solution to do that as a plugin or docker within UnRaid.