Hallo everybody, or just anyone who reads this :)

 

I'm a student from Denmark who studies 'Power Engineering', but allways had an instressed in software, servers and so on.

I recently found an old server, and decided to finally copy all my DVD's and music to one of the many hardisks that I have laying around.
Unraid was the way to go, since I have ALOT of different harddisks in different sizes. But before I acually buy anything, I just have a few questions, well, actually just one for now.

 

But, if I fill a server up with, lets say, 4 x 1TB harddisks, so 3 TB total (1TB Parity). If I then fill it with 500GB data, and one of my hardisk suddenly decides to break, and I don't have another haddisk laying around, so I just carry on (2TB total (1TB Parity)). But suddenly another harddisk fails! #SadFace. Can I still use it?

I may ask weird, english isn't my strong side. But is the setup it redundant to the point of the 1TB? Can Unraid utilise the rest of the drives, if the capacity still fits in the remining drives? If you have a system, can you reduce the drives by one and tell Unraid, to make the remining drives act as the 'new' system that's redundant?

 

I've tried to ask in a number of ways, so you'll hopefully understand, what I'm acually trying to ask :)

 

Have a fantastistic day/evening/night, and remember! don't eat glue! Even if it's green with glimmer in it!

 

Best Regards

Michelle Bausager

Single parity allows one missing disk. Size of disks or amount of data doesn't matter. Parity doesn't even know anything about the data. The parity calculation uses parity PLUS ALL remaining disks to calculate the bits for the missing disk. 

 

Since all disks are needed to rebuild a missing disk it's important that all disks are reliable. Just a bunch of old disks you happen to have may not be the best way. And fewer larger disks are better than more smaller disks since each additional disk is an additional point of failure. 

Fair. I have two 4TB Seagate Ironwolf, and are planing on getting more of those. So is it then possible to expand the system with more 'Parity' and 'Disks'? So if I use one 4TB as 'Parity' and one as a 'Disk', is it then possible to expand the system with more of the same disks (Or disks with a bigger size (I know Parity drives should be a least as big as the bigest drives in the 'Array'))?

I just feel so bad not useing working harddisks, I know it's not every effective to recycle electronics, so is it possible to make two pools of harddisks(Like more 'Arrays'?)? Like one with the stable dedicated NAS-drives with 'Parity' and so on, and another pool with the old harddisks with seperate 'Parities'? Or is there a good benchmark too see what harddisks acually are stable enough to use in a NAS environment? Otherwise I don't really know what to do with most of the working harddives :c

You can expand as much as you like (and your license allows), but what @trurl pointed out is any recovery of a failed disk (or 2 failed disks when dual parity is in place) depends on the reliability of all other disks to do so correctly.

 

When you add more disks of questionable quality, chances become higher that more disks fail than parity can recover and data loss is the result.

 

Most disk vendors have a (Windows) application to validate the health of their disks. You can use this to verify each disk before using it in Unraid.

 

Another approach can be to use the 'preclear' tool to test disks in Unraid before taking them into production.

 

Okay. Thanks for the answers, I'll dubble check my harddisk with preclear to make sure of the stability, not use smaller harddisks and make sure that I have access to replacement harddisks, that are minimum the size of the failed harddisk and with a maximum size of the parity disks.
Again, thanks for takning some time to answer some stupid questions c: You'll definitely see my again, when I run into a wall again.

 

 

Oh, I don't know this community that well, but when a post-tread, has ben resoved, should I delete or hide the tread? :$

14 minutes ago, Michelle Bausager said:

should I delete or hide the tread?

Neither, leave it as is, it might help others, if it was a problem you could also edit title and add [solved].

2 hours ago, Michelle Bausager said:

Oh, I don't know this community that well, but when a post-tread, has ben resoved, should I delete or hide the tread?

The approved way is to edit the first post in the thread and add [SOLVED] to the title.   That leaves the thread and solution available for other to find in case it helps them.