Hi all,

 

I've got a new Unraid build - a simple box with 4 HDDs (one as a parity) alongside an SSD for caching.

I've got a few days left on my trial and so far it's been great.

 

Before I go ahead and purchase, I wanted to clarify on something.

I've gone through various bits of documentation and read countless threads on this forum but I can't seem to find a definitive answer to this question...

 

1. In my 4 HDD setup (with one as a parity), if I were to lose one of those non-parity disks, can 100% of that data be recovered from the parity?

2. If this was to happen, is the rebuild process straight forward i.e. pop in a new disk and hit a "rebuild" button?

3. If my USB stick died, would I need a backup of anything to get it all up and running again or do I simply replace the USB stick?

 

Thanks - and sorry if these questions have been asked a billion times already!

Just now, WelshDev said:

1. In my 4 HDD setup (with one as a parity), if I were to lose one of those non-parity disks, can 100% of that data be recovered from the parity?

 

Yes

Just now, WelshDev said:

2. If this was to happen, is the rebuild process straight forward i.e. pop in a new disk and hit a "rebuild" button?

 

Yes

Just now, WelshDev said:

3. If my USB stick died, would I need a backup of anything to get it all up and running again or do I simply replace the USB stick?

 

Mostly yes.  Keep a backup of the stick somewhere else.  (You can create a backup from within the GUI)

You'll definitely need the contents of the config folder on it to place onto the replacement stick.  

 

After that, the GUI will walk you through replacing the registration key tied to the original to the new one.

 

Worst case scenario if you lose the backup is that you'll have lost the assignments of the disks, so you reassign them appropriately, and then contact limetech to get a replacement key for the new one.

Sweet, that's all my questions answered.

I'll be hitting that purchase button shortly

 

Thanks!!

17 minutes ago, WelshDev said:

if I were to lose one of those non-parity disks, can 100% of that data be recovered from the parity?

Just thought it might be worthwhile to elaborate on this beyond the answer already given.

 

The data can be recovered from the parity calculation by reading parity and all remaining disks. The parity disk by itself can't recover anything.

Just  a bit more info about how parity works:

 

18 minutes ago, WelshDev said:

1. In my 4 HDD setup (with one as a parity), if I were to lose one of those non-parity disks, can 100% of that data be recovered from the parity?

Yes, mostly.  To rebuild a failed disk, you need the parity drive and ALL other intact data drives.  The Parity disk is not a backup, it contains no data.  It's just a calculation that is the sum of bits at the same location on all drives,  From the parity calculation AND reading the bits on the other data drives, unRAID can figure out what it missing on from the failed drive and rebuild it on a new drive.  All your other data disks must be able to be successfully read.

 

You need a backup strategy to protect against data loss.  Parity only protects against drive failure.

in other words, "yes"  

Thanks for clarifying!

I'm currently getting it setup to sync to Backblaze so that's my backup sorted