In choosing between Raid 1 and Raid 5 configuration for the PR4100 I would like to know that once my volume is degraded due to a single disk failure, can I access my data to copy it to a backup drive before attempting to rebuild the volume on a replacement drive? My understanding is that while I am rebuilding the replacement drive, my volume is not available (for both Raid 1 and Raid 5). Is this correct? I have read that rebuilding can take a long time (days), and I do not want to be locked out of access to my data if possible.
I realize that separate backup is necessary and I intend to use my existing two NAS’s (a 2 TB MyCloud Mirror; and a 4 TB Dlink DNS 343) as backup to my PR-4100. What are the drawbacks you refer to with Raid 1?
In Raid 5, data can be recovered when the Raid is working. Recovery is faster in Raid 1. Recovery is slow in Raid 5 due to parity and calculations for rebuilding the data storage. Raid 1 does not do any error correction and detection whereas Raid 5 has many techniques for error correction and detection.
