I’ve run into a problem that I can’t figure out. I have a 918+ and recently followed Synology’s guide for swapping out the smallest drive for a larger one to increase storage space. This process went seamlessly and I can see in Storage Manager that drive 4 is now the largest one.
The problem is when I go to Volume > Settings, there is no option appearing to increase the volume size. The NAS is running DSM 7.2-64561 and set up as a RAID 5 with btrfs file system.
Since you are using RAID5 and not SHR1 you have to replace all the drives to get more space back. With RAID5 all drives act as the size of the smallest drive.
Does this calculator reflect your drive space?
Capacity for RAID 5 = (number of drives – 1) x (smallest drive size)
The RAID calculator may provide insight as to whether more drives need to be replaced before the storage pool can be expanded.
I realize that my home NAS is set up as SHR, and when I added a drive to it, I had the same issue with not being able to increase the volume size. If I can get that one to work, I can migrate the data to it and reformate the RAID 5 one.
I appreciate your help.
So with SHR you take the largest drive and use that for redundancy. So the first drive you add thats larger will not give you space. Only the second one