After doing a lengthy search (and finding some relevant information), I wanted to ask a specific question about final volume capacity in larger sized drives. Now that I understand the reason between the 'advertised' size and what we see on our Disc Utilities, I now know that a 1TB drive shows up as a 931GB volume. While I don't want to give away that 69GB capacity, I guess I'm good with that. My specific question is that I've just installed two WD RE3 1TB drives as a RAID 1 in a Synology NAS. Install went very easily. What I am now seeing as an available capacity is 912GB. A full 19GB less than the 931. I also understand that the OS creates folders, and future room for updates. But 19GB seems like a lot. At least to me. The Synology OS needed 300MB of room, and shows in the DSM panel. So, my elementary question is. . . . . does this seem correct? I have heard that larger capacity drives end up less than 93% of their advertised capacity. If anyone has any pointers or information, I'd appreciate the education. Otherwise, it seems like something may be wrong with the firmware etc in the drives themselves. Thanks for any info.