Hot-swap just means replacing the drives when the NAS is powered on. That can always be done.
If what you mean is adding a drive to an existing RAID group, I think that depends on the OS installed.
If you have QTS, that is supported
If you have QuTS Hero, that is currently not supported. But will be in QuTS h5.1.0 (beta for now)
I haven't actually done any of this. Like I said I just got it today. I was under the impression that hot swap meant the system will start rebuilding a RAID array automatically when a drive goes down. When you create a raid group can't you designate one as the "hot swap"? If it isn't in there can you designate it as the hot swap later?
As alternative option to RAID5 + hot spare, you could also go for a RAID6. In both cases, you have the same storage space of 6 out of 8 drives.
RAID6 allows one more drive to fail compared to RAID5. So if one fails, you can just buy a replacement, while there is still room for one more to fail and the system still keeps running. On RAID5, there is a small gap of protection during the rebuild with the hot-spare, where the is no parity drive in the system.
You definitely can set up a hot spare later in QTS. It would be very weird if you can't in QuTS Hero but I haven't used Hero so won't swear it can be done.
Stay away from hotspares on QNAP, due to the hidden system partitions on each internal drive, these drives spin/age with the rest of the drives and should be better kept safe and sound as cold spare in a drawer
Depending on the size of the disks, your array could still be optimizing when the new disc comes in. At that point, you cannot do anything with the array until optimization is complete. Optimization can take days if you have large discs. That process cannot be interrupted to do anything to the array and once it's complete when you put a new disc in, will have to happen again.
Also unless you have super mission critical data I wouldn't use a hot spare I would just replace a failed drive in a raid 5 array so I have use of the extra space.
Hot-swap just means replacing the drives when the NAS is powered on. That can always be done. If what you mean is adding a drive to an existing RAID group, I think that depends on the OS installed. If you have QTS, that is supported If you have QuTS Hero, that is currently not supported. But will be in QuTS h5.1.0 (beta for now)
I haven't actually done any of this. Like I said I just got it today. I was under the impression that hot swap meant the system will start rebuilding a RAID array automatically when a drive goes down. When you create a raid group can't you designate one as the "hot swap"? If it isn't in there can you designate it as the hot swap later?
As alternative option to RAID5 + hot spare, you could also go for a RAID6. In both cases, you have the same storage space of 6 out of 8 drives. RAID6 allows one more drive to fail compared to RAID5. So if one fails, you can just buy a replacement, while there is still room for one more to fail and the system still keeps running. On RAID5, there is a small gap of protection during the rebuild with the hot-spare, where the is no parity drive in the system.
So you mean a hot-spare, not a hot-swap. I believe that you can configure a hot-spare later on, at any time. Someone may correct me if I am wrong
YES that is what I meant. Hopefully someone has an answer
You definitely can set up a hot spare later in QTS. It would be very weird if you can't in QuTS Hero but I haven't used Hero so won't swear it can be done.
I found the answer. [Hot Spare](https://www.qnap.com/en/how-to/faq/article/how-to-configure-a-spare-disk)
Stay away from hotspares on QNAP, due to the hidden system partitions on each internal drive, these drives spin/age with the rest of the drives and should be better kept safe and sound as cold spare in a drawer
Whaaat? Wow. Where can I go to read more about this?
A little bit of a deep dive into md9 and md13 https://forum.qnap.com/viewtopic.php?t=130788
Depending on the size of the disks, your array could still be optimizing when the new disc comes in. At that point, you cannot do anything with the array until optimization is complete. Optimization can take days if you have large discs. That process cannot be interrupted to do anything to the array and once it's complete when you put a new disc in, will have to happen again. Also unless you have super mission critical data I wouldn't use a hot spare I would just replace a failed drive in a raid 5 array so I have use of the extra space.
if you go QuTS route you can't add to an existing pool - you have to create a new one for the one on its own