RAID arrays of different sizes

So after buying a few 5tb WD Red drives it appears they've now discontinued them and since thrown my plan of expanding my home server's capacity with similar drives when the time comes out the window.

My question is, is it possible to have multiple arrays where one array is smaller than the others? Not looking to add a harddrive to the existing RAID 5 (know it would match the smallest drive in this instance) but creating subsequent arrays with additional 6tb drives; I assume the controller will just treat it as a new space and isn't restricted to match an existing smaller RAID 5 array size based on the smaller capacity?

Yes - I don't know of any raid controller that doesn't allow you to have different size or even different level arrays.

E.g. One of my servers at work has 3 arrays:
2x 146GB Drives in Raid 1
8x 300GB Drives in Raid 10
2x 600GB Drives in Raid 1

Thanks for the confirmation Armageus - suspected that was the case (we all know what assuming did though) before adjusting how I was using the "leftover" drives from the 6 I originally bought.

I really wouldn't advise using raid 5 with such large drives.

The rebuild time for a raid 5 array with 5tb disks is ridiculous, add in the huge performance degradation inherent with raid 5 rebuilds and its quickly becomes an inappropriate level of raid.

Would it be possible to use larger disks in raid 1? or better still, more disks in raid 10? You'll still be hit with long rebuild times, but performance deg on rebuild will be much less and you'd get a massive performance boost with raid 10.

Have a look at UnRaid. It will allow you to have any number of different sized drives in an array.

Wilderbeast said:

I really wouldn't advise using raid 5 with such large drives.

The rebuild time for a raid 5 array with 5tb disks is ridiculous, add in the huge performance degradation inherent with raid 5 rebuilds and its quickly becomes an inappropriate level of raid.

Would it be possible to use larger disks in raid 1? or better still, more disks in raid 10? You'll still be hit with long rebuild times, but performance deg on rebuild will be much less and you'd get a massive performance boost with raid 10.

Click to expand...

RAID 5 seemed like a good compromise on space to redundency; my plan was although the media is "replaceable" in the event of a failure it'd make time reacquiring it less of an issue if say it was in a simple RAID 0 etc. - are disk failures on a rebuild all that common?

neodude said:

Have a look at UnRaid. It will allow you to have any number of different sized drives in an array.

Click to expand...

Yes have looked at unraid before but wasn't looking for different sized disks in the RAID, more so multiple RAIDs of different sizes (one 15tb, 3 18tb etc).

I mean you're looking at a rebuild time of days if not weeks depending on the controller.

And in that time if another drive fails you lose everything.

Plus a drive is more likely to fail during a rebuild due to the extra load

hellarda said:

I mean you're looking at a rebuild time of days if not weeks depending on the controller.

And in that time if another drive fails you lose everything.

Plus a drive is more likely to fail during a rebuild due to the extra load

Click to expand...

This.

How much more are 6TB drives - it will just treat them as 5TB. But I would strongly suggest you rebuild the array into R6 or R10.