I know. It's called hot swapping. But what I meant is the size. Having 6x 3.84 TB NVMe in an existing raid array and wanting to upgrade to 6x 7.68 TB is possible but not as straight forward.
It would be less straight forward only if you have a single server and that server has only a few SSD slots, which are all occupied.
Otherwise, you can just move the old SSDs to another server, plug the new SSDs, copy the old content in the new SSDs and that is it. No reboot needed. Normally any server should have a separate small boot SSD, typically an M.2 SSD on the MB or sometimes a small USB memory plugged internally in the MB, with the operating system, which is not affected in any way by the mounting or unmounting of the other SSDs or HDDs that contain user data.
When the second server does not have free SSD slots, it must be taken temporarily offline and its own SSDs must be removed until the old SSDs of the first server are copied. In the worst case one would have to do three pairs of SSD unplugging and plugging multiplied with the number of SSDs in one RAID array, six in your example, to replace the SSDs in the first server with the new SSDs, then replace the SSDs in the second server with the old SSDs, then restore the SSDs of the second server. Even so, I would consider such a procedure as straight forward, as all the operations would take a few minutes at most, which would be a much shorter time than required for the copying of the old content to the new SSDs.
When you have a single server, then the alternative of using shared storage would also not exist. Except for home servers, the use of single servers should be rare, because even when a single server has enough capacity there should be a backup for it.
Comments
I know. It's called hot swapping. But what I meant is the size. Having 6x 3.84 TB NVMe in an existing raid array and wanting to upgrade to 6x 7.68 TB is possible but not as straight forward.
It would be less straight forward only if you have a single server and that server has only a few SSD slots, which are all occupied.
Otherwise, you can just move the old SSDs to another server, plug the new SSDs, copy the old content in the new SSDs and that is it. No reboot needed. Normally any server should have a separate small boot SSD, typically an M.2 SSD on the MB or sometimes a small USB memory plugged internally in the MB, with the operating system, which is not affected in any way by the mounting or unmounting of the other SSDs or HDDs that contain user data.
When the second server does not have free SSD slots, it must be taken temporarily offline and its own SSDs must be removed until the old SSDs of the first server are copied. In the worst case one would have to do three pairs of SSD unplugging and plugging multiplied with the number of SSDs in one RAID array, six in your example, to replace the SSDs in the first server with the new SSDs, then replace the SSDs in the second server with the old SSDs, then restore the SSDs of the second server. Even so, I would consider such a procedure as straight forward, as all the operations would take a few minutes at most, which would be a much shorter time than required for the copying of the old content to the new SSDs.
When you have a single server, then the alternative of using shared storage would also not exist. Except for home servers, the use of single servers should be rare, because even when a single server has enough capacity there should be a backup for it.