Hello,
maybe you contribute to this thread by describing experiences you've made (or want to avoid) when expanding a RAID5.
Thinking about risks expanding a RAID5, the following dangers come to my mind:
RAID5 is your data's lifesaver when one hdd becomes defective.
=> When adding more than one hdd to an existing RAID5 at a time there is a higher risk while reshaping (adding the new hdd's to the RAID5). This can be avoided just adding one hdd at a time.
Disadvantage of this process is the time needed for reshaping. This time is nearly equal to adding x hdds at a time. For example adding one 4TB hdd to my RAID5 (4x4TB) takes approx. 24 hours, adding two 4TB hdds at a time takes 24 hours too.
Please correct me if I'm wrong and any addition is welcome.
Kind regards tsch