I am planning to have a 5x 4TB RAIDZ1 array which is 16TB usable space. What I expect is data wouldn't loss when lossing one disk. However, issue regarding to Non-recoverable Read Errors (NRE)/ Unrecoverable Read Error(URE) come out when i do some search on RAID5 rebuild.
For non-enterprise hard drives, NRE/URE rate is normally 1 per 10^14 bits read, which means that NRE/URE occurs every 11.37TB. For my case, when array is full and one disk fails, system have to read 16TB data to rebuild the array. There is a very high probability that NRE/URE occurs during rebuild process.
My questions are:-
(1) What will Freenas do when NRE/URE occurs?
(2) Can Freenas still finish rebuilding if there is NRE/URE occurrence in the process?
(3) If I use ECC ram & cpu, can I ignore this issue?
(4) If answers of question 2 & 3 are "No", it means raid 5 rebuild process fails most of the time for array over 11.37TB usable space, right?
(5) Without using expensive enterprise hard drives, what other measures can be taken to protect an array from one disk failure under NRE/URE rate of 1 per 10^14 bits read?
Many thanks
For non-enterprise hard drives, NRE/URE rate is normally 1 per 10^14 bits read, which means that NRE/URE occurs every 11.37TB. For my case, when array is full and one disk fails, system have to read 16TB data to rebuild the array. There is a very high probability that NRE/URE occurs during rebuild process.
My questions are:-
(1) What will Freenas do when NRE/URE occurs?
(2) Can Freenas still finish rebuilding if there is NRE/URE occurrence in the process?
(3) If I use ECC ram & cpu, can I ignore this issue?
(4) If answers of question 2 & 3 are "No", it means raid 5 rebuild process fails most of the time for array over 11.37TB usable space, right?
(5) Without using expensive enterprise hard drives, what other measures can be taken to protect an array from one disk failure under NRE/URE rate of 1 per 10^14 bits read?
Many thanks