I have an old 2TB Seagate Barracuda drive and I want to build a zfs mirror. I don't think I can buy a 2TB drive with exactly the same size (identical number of bytes), but on the other hand the old drive is still in good condition and I don't want to throw it away. I'm going to buy another 2TB drive, which might have slightly different size and build a zfs mirror out of those 2 disks. Whould it be OK? Should I expect any performance penelalties and may be some other issues, caused by the fact the the drives are not identical in terms of size?