jj lolo

Thanks for the explanation. I understand that each drive is independent and could be read directly. I guess what I don't understand is that if in my case I have 1 parity drive, and 3 data drives (4X14TB total disks) drives how the parity drive can duplicate the data of the 3X data drives and store 3X14TB of data on just one 14tb drive and say if one of the data drives dies, then how it can recreate the contents of that drive from just 1 parity drive, and in that scenario, how long it takes and the calculated failure rate could be on rebuilding such a large drive? What am I missing? Similarly, if I'm paranoid, and have two parity drives, how is performance impacted? What would you recommend as the ratio of parity vs non parity drives? What is the disadvantage of unraid?

I've just build a NAS to use for either unraid or xpenology and just ordered 4x14TB seagate enterprise drives. I'm trying to compare unraid vs raid 5 and 6 reliability rates (including a full recovery- as we all know other drives can fail during the recovery period). While I understand that data loss is more limited, I'm wondering how to calculate the chance of ANY data loss. Using https://wintelguy.com/raidmttdl.pl and the variables below, Using raid 5- I get a probability of data loss over 10 years of 0.0014504202932147 And with raid 6 I get a probability of data loss over 10 years of 0.0000002555505010 1. I was wondering what they would be for unraid with one and two parity drives since I couldn't find an online reliability calculator for unraid? Or is it simply the same as above but if loss occurred instead of loosing 100% of your data you loose some? 2. Is there a way to numerize the probablility? 3. How fast are the rebuild times compared to traditional raid 5/6? 4. I didn't find a space calculator other than for just one parity drive. Is there one? Are there speed advantages (e.g. Raid 6 has 2X read speeds). 5. Which license would I need? Thanks in advance for your help! Here were the variables I used: Total Usable Storage Capacity (GB) 42000 Number of RAID Groups 1 Number of drives per RAID Group 4 Total Number of Drives: 4 Drive Capacity (GB) 14000 Throughput (MB/s) 600 Drive MTBF (hour) 876000 Drive Annual Failure Rate (%) 1