Power outage resulted in parity drive not being recognized

[max.prime]

Yesterday I had a power outage while I happened to have my UPS disconnected.  When I turned my server back on, Unraid did not recognize my parity disk - it was as if it was disconnected.  I didn't notice this until a this morning, well after I had spun up the array.  While I didn't make any major changes to the filesystem, I reckon that logs were generated and several automated tasks wrote to the array.  When I noticed the parity drive wasn't online, I rebooted, and there it was as an unassigned disk.  When I assigned it as the parity drive it was as if it was a new disk (there was a blue dot) and is now writing a parity sync.

 

I'm not sure how concerned I should be.  It kind of defeats the purpose of a parity drive.

 

I've attached a SMART report (post power outage) of the parity disk, along with and diagnostics, and previous syslog (after the power outage). 

logs.zip

[Frank1940]

2 hours ago, max.prime said:

I'm not sure how concerned I should be.  It kind of defeats the purpose of a parity drive.

 

 

It is very usual for parity rebuild after a unclean shutdown.  Especially since it was the result of a power failure.  (I am going to paraphrase your statement--  It kind of defeats the purpose of a UPS.)  The parity drive not being assigned is a bit of anomaly. 

 

Do you know if there was any disk activity at the time of the power failure?  If so, do you know what was being written to the server?  You will want to check to see if this information was correctly and fully transferred to the server before the shutdown.  If not, you will have to deal with this situation.  (There is a way to find those files written about the time when the shutdown occurred but it is a bit tedious.)

 

Any writes to the array while you did not have a parity assigned should have proceed normally.  (You don't actually need a parity disk assigned for Unraid to work.  In fact, it is often recommended that when one is first 'loading' an array with a massive amount  of data to unassign the parity drive(s) until the loading is finished.  Then assign parity and allow it to build to provide protection.)

 

Let the parity check rebuild finish.  Check to see that it did not find any other issues.  Then have a look at the data on your server. 

 

One more thought.  Unraid is not a backup.  It can be a part of your backup solution.  You need another copy of any data that is irreplaceable on some other device. 

Edited February 24 by Frank1940