April 3, 201511 yr I do parity checks once a month on the second day of month. It was complete randomness that parity check finished in morning and about 12 hours or so later power to house went out. Parity morning of showed NO errors! Since power went out the default is for server to do a parity check upon restart...I let it complete. Now it says "Last checked on 4/3/2015 4:05:42 AM, finding 7 errors.)" So what does this mean? If more information is needed...walk me through how to get it so I can help you guys help me. I am not touching ANYTHING till I hear more... Thank you
April 3, 201511 yr Author I forgot to include. Unraid 4.7 6 drives total each 2TB 1 parity 2TB drive 5 data 2TB drives not sure what other information is needed
April 3, 201511 yr the parity drive is used to recreate from scratch a complete drive the parity check checks if the parity drive is able to do this, if it finds that parity does not correspond with your actual drives it corrects the parity drive. your power failure happened during a write, data on the drive changed but parity was not changed. the parity check found that discrepancy and fixed it, thats what is it for. do not worry, all is fine.
April 4, 201511 yr Author Ok... I thought that was the process but have also read in past that is not always the case. I played it safe and asked questions first instead of making the situation worse. Thank you for assistance.
April 4, 201511 yr No problem whatsoever, and you are even right. The parity drive makes sure that it is able to recreate a disk in its current state, this means that: suppose you have a power failure that corrupts your drive, the parity will then make sure that it is updated in such a way that it will be able to exactly recreate your corrupted drive. This is also the reason why people keep on saying that parity is not a replacement for backups.. Parity also cannot tell you where a paritiy errors resides, you get a parity error notice but you cannot know what file (if any file , could also be empty space on the drive) the error is in. Parity will never help in corrupted files, it helps in getting back a fully failed drive. For corruption you would need some kind of checksum process, there a few ways of doing that out there, from my perspective however that is a functionality so close to the base functionality of unraid itself that I am waiting for limetech to implement it themselves..
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