My companies Synology NAS (DS1618+) has 6 12TB drives in a RAID5 array. One of the drives went from abnormal to failing. We do not have a "hot spare". Co-workers depend on this on a daily basis so I guess my question is, are we looking at any downtime after replacing the drive? It is my understanding the new drive can be populated while the system is still operation or is that false? I found plenty of information on how to do this, but none on the ramifications.
Before you ask, yes we do have a backup.
In case it matters, we have a capacity after RAID and formatting of 34TB and we only use 18TB.
