autoexpand & smaller disk

[MtK]

Hey,
for this question, let's assume we have a vdev of 6 drives where 5 are 1TB and 1 is 500GB. so the entire pool would be built according to the smallest drive as if they were all 6 x 500GB. So, replacing that 1 x 500GB with a 1TB drive would make the entire pool expand/grow into 6 x 1TB.

What about the opposite case where we have 1 x 1TB and 5 x 500GB, and we still have a pool acting as 6 x 500GB, can we replace that 1TB drive with a 500GB disk and keep the pool the same size as before (6 x 500GB)?
(of course without loosing any data)

MtK

 

[cyberjock]

Sure can. Just be careful as one disk might be 500.2GB and another might be 498.6GB. Those slight changes might make that 500GB disk you buy be ever-so-slightly smaller, but smaller nonetheless.

I got a replacement drive via RMA that had a different firmware version that was a couple of megabytes smaller than the drive we pulled about 7 years ago. We couldn't add it to our hardware RAID because of that smaller size. We called the manufacturer and all they could say was "sorry. We recommend you buy our next bigger disk size to ensure you don't have this problem" so we went to a competitor. :)

 

[MtK]

thanks
assuming i get this 0.1MB smaller drive, would the system alert me, I'm about to use a drive that is smaller than required and actually prevent the usage of that drive?

 

[cyberjock]

It will fail when you try to do the disk replacement procedure and will give you an error.

FreeNAS by default creates 2GB of swap space on every disk. If your disk is less than 2GB(or whatever size you choose to you when you created your pool initially) smaller then you can change the size of the swap space so that you will have enough space for your pool's partition. But if its bigger than 2GB(or whatever size you choose to you when you created your pool initially) then you won't have any alternatives except to get a bigger disk.

 

[MtK]

i didn't mean to get a 0.1MB disk, I meant a disk smaller by 0.1MB than the others in the vdev... ;-)