My power just went out....

[Christopher Ward]

what a bad time for a power cut, i was in the process of replacing a 3tb drive with a 4tb, it had only just started.

checking zpool status still shows resilver in progress, should i be worried?

Code:

[root@MEDIASERVER ~]# zpool status																								
  pool: RaidZ2																													
 state: ONLINE																													
status: One or more devices is currently being resilvered.  The pool will														
		continue to function, possibly in a degraded state.																		
action: Wait for the resilver to complete.																						
  scan: resilver in progress since Tue Dec 26 14:43:07 2017																		
		1.84T scanned out of 22.9T at 401M/s, 15h19m to go																		
		179G resilvered, 8.01% done																								
config:																															
																																	
		NAME											STATE	 READ WRITE CKSUM												
		RaidZ2										  ONLINE	   0	 0	 0												
		  raidz2-0									  ONLINE	   0	 0	 0												
			gptid/2640e9fe-7811-11e5-bb3e-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/853133de-a5d6-11e6-84d5-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/7ec2f55d-df6a-11e6-a9c0-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/71add977-fb4a-11e6-8374-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/b76b8cd3-e1b4-11e6-98a3-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/d2d515de-0f39-11e7-b8b1-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/df4ec194-fe7a-11e6-be9d-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/291ed957-7811-11e5-bb3e-0cc47a6ae76e  ONLINE	   0	 0	 0												
			gptid/0d7329d5-ea4b-11e7-b159-0cc47a6ae76e  ONLINE	   0	 0	 0  (resilvering)								
			gptid/29e70777-7811-11e5-bb3e-0cc47a6ae76e  ONLINE	   0	 0	 0												
																																	
errors: No known data errors																										
																																	
  pool: freenas-boot																												
 state: ONLINE																													
  scan: scrub repaired 0 in 0h4m with 0 errors on Tue Nov 21 03:49:39 2017														
config:																															
																																	
		NAME										  STATE	 READ WRITE CKSUM													
		freenas-boot								  ONLINE	   0	 0	 0													
		  gptid/a501240c-7803-11e5-8b89-0cc47a6ae76e  ONLINE	   0	 0	 0													
																																	
errors: No known data errors  

EDIT: second power cut while it was resilvering again

 

[Jailer]

Good lord get a UPS! Let it finish and see what the output of the scrub is.

 

[scrappy]

Do a scrub after resilvering is complete. Doubt anything bad happened.

 

[scrappy]

Good lord get a UPS!

Couldn't agree more! lol

 

[Christopher Ward]

Do a scrub after resilvering is complete. Doubt anything bad happened.

OK i'll let it finish and do that.....yeah i really should get a UPS just haven't got round to it yet, if i lose any data that might be what it takes

 

[rs225]

Any problem with the resilver is unlikely, since it is going to actually back up and redo some of the resilver when it restarts.

 

[Arwen]

Uh, guys, ZFS was designed WITHOUT the need for a UPS. (Of course, a UPS is very nice to have for the home, and necessary for office environments in my opinion.)

Remember, ZFS is a copy on write file system. So it updates data, file attributes, directorys, and file system configurations into free, empty space. Then, when completely written, updates something called an Uber block. Each disk has them, (well, probably 2 sets, beginning of disk and end). These describe the latest state of the ZFS pool at the time it was last written to. So if a write was in-complete, then old data is still good. And a re-silver will simply resume where it left off.

The designers of ZFS tested some of the concepts, like Uber blocks, by using power fails.

 

[rs225]

Just make sure your controller and disks are respecting cache flushes. If they don't, then you get to restore from your well kept backups.