Drives - What is recommended & what is overkill

[Ira]

Hi

I cant fint a thread like this so im trying to post if there is a thread i have missed please let me know.

I have been a happy user of Unraid for around 1 year now and most of the time it work (when i dont fuck up my self).

I had some problems with my drives where someone commented that it was overkill with 2 Parity drives when i have 2 normal drives so this thread.

My setup is:
2 x Exos 14 TB Parity
2 x Ironwolf  12 TB Disk
2 x EVO 850 500G Cache

Now when is it overkill and when is it just right?

Both Exos are bought from same seller at same time and Ironwolf are also bought together from an other seller.
I know some will say that you should ever buy from same batch but well i prob did.

So in case some fail is my Parity over kill?

If yes can i remove one of my Parity and reuse for other use?

Looking forward to hear your thoughts on this.

[itimpi]

There is no ‘right’ answer - it is all about the amount of risk you are prepared to take and how good your backup strategy is.  For most people with only a few data drives they may prefer to use an additional drive for backup rather than as a second parity.  Do not forget that parity is primarily about high availability and simple hardware failures, it does not guarantee you will not lose data.   There are lots of ways to lose data other than drive failure and thus the need for a backup strategy that suits your needs.

 

having 2 parity disks allows for a second drive failing while you are trying to rebuild a failed drive.   The likelihood of this is relatively low but goes up as the number of drives and the drive size increase.    I know of people who have a good backup strategy running with no parity at all even though they have quite a few drives.

[Ira]

Thank you for your input

My data is mostly stuff i can get again if all fail so no company info or family photo that is one of a kind.

So in my case if i wanna downgrade to 1 Parity drive can i just take the array off-line power down and then remove the drive and start up again?

 

[itimpi]

3 minutes ago, Ira said:

So in my case if i wanna downgrade to 1 Parity drive can i just take the array off-line power down and then remove the drive and start up again?

Yes - you just need to unassigned it and restart the array.   Physically removing it is optional.

[Ira]

Thank you for your thoughts and input

I love the great help you can get here even if some questions are very n00b  

[trurl]

And of course you can add it to the array as a new data drive.