Raid Z1 vs Z2

[Savell Martin]

Hey Guys,

So I currently run Raid 5 with 4x 3tb drives.

I am building a new box for FreeNAS and curious about Raid Z1 with 4 drives.
I know its not approved of, but would there be an issue running it?
As in, if I lose a drive would I lose my whole storage pool?

Or would the 1 drive kick in like Raid 5?

If it will continue to work fine, will there be any performance impact on running Z1 with 4 drives?
How much extra would it be worth running with 5 drives?

Thanks

 

[warri]

I know its not approved of, but would there be an issue running it?
As in, if I lose a drive would I lose my whole storage pool?

There is no issue running 4 drives in a Raid-Z1, in the worst case a slight performance penalty.

Or would the 1 drive kick in like Raid 5?

Yes.

If it will continue to work fine, will there be any performance impact on running Z1 with 4 drives?
How much extra would it be worth running with 5 drives?

I can't quote any numbers, but I'm also running a Raid-Z1 with a non-optimal number of disks. For my personal usage the performance is sufficient (and also my hardware is not fast enough to see any difference).

 

[gpsguy]

Rather than saying "not approved", I might say "not recommended" for large drives.

warri's answers are correct.

The concern is that if a drive fails, you replace it, and during the resilvering process (which puts a big load on the system) another drive fails. This is where RAIDz2 can offer more protection.

Since RAID <> backup, hopefully you will be backing up irreplacable data.

I know its not approved of, but would there be an issue running it?

 

[Savell Martin]

Perfect thanks a million for the answers :)

 

[cyberjock]

See my sig that says RAID5 is dead. That should scare you enough to turn away from RAID5, especially 4 years after RAID5 was declared "dead".

 

[Savell Martin]

Meh...
Im not to scared :P