sibi78 Posted March 7, 2019 Share Posted March 7, 2019 Couple of basic clarifications on the parity drive: 1) It seems the parity drive itself does not have any file system, and it is used as a raw drive to store the calculated parity bits. Is this correct? 2) I presume that UNRAID wouldn't sync parity after every clean reboot - i.e., if I stop the valid array before reboot, and perform a clean reboot, Unraid wouldn't sync parity every time I reboot the system, right? Thanks! Quote Link to comment
wgstarks Posted March 7, 2019 Share Posted March 7, 2019 10 minutes ago, sibi78 said: Couple of basic clarifications on the parity drive: 1) It seems the parity drive itself does not have any file system, and it is used as a raw drive to store the calculated parity bits. Is this correct? 2) I presume that UNRAID wouldn't sync parity after every clean reboot - i.e., if I stop the valid array before reboot, and perform a clean reboot, Unraid wouldn't sync parity every time I reboot the system, right? Thanks! 1) Correct. 2) Correct again. You don’t actually have to stop the array though. Selecting “reboot” will stop the array as part of the process. Quote Link to comment
JonathanM Posted March 7, 2019 Share Posted March 7, 2019 21 minutes ago, sibi78 said: I presume that UNRAID wouldn't sync parity after every clean reboot - i.e., if I stop the valid array before reboot, and perform a clean reboot, Unraid wouldn't sync parity every time I reboot the system, right? The parity sync is actually a little different. What you are describing is a parity check, which verifies that parity is still synced up. Normally parity is built (synced) when the array is first commissioned, and it stays synced during all normal operations. The issue with an unclean shutdown is that writes to the data disks are prioritized, so hopefully your data stays safe. The parity disk may not catch all the writes if the rug is pulled out from under the server, so when the system is brought back up the server needs to check to make sure all the changes to the data disks were committed to parity. Unraid is constantly syncing parity for every write operation, which is why I felt the need to write this clarification. You stated unraid wouldn't sync parity after a clean reboot, which is wrong. It won't force a CHECK of parity, it just assumes everything is still in sync and continues syncing new writes. Quote Link to comment
sibi78 Posted March 7, 2019 Author Share Posted March 7, 2019 Sure, that clarifies. Thanks! Quote Link to comment
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