Slow Scrub Speed (RAID-Z1 5x3tb Drives)

[Fattrain]

Hey guys, I've had my FreeNAS system up and running for a little over a year with monthly scrubs scheduled. They didn't used to take very long (in fact most of the time I wouldn't notice) but now scrubs seem to take DAYS instead of hours. My monthly scrub started June 1st @ Midnight and it's STILL going. I don't have millions of tiny files or anything, most of it is either music and/or couple gb video files.

Specs:
5x WD WD30EFRX Red 3TB
i7-4790k processor
32gb of ram
I still have about 2.2tb free space

When I do a Z Pool Status command I get the following:

Code:

  scan: scrub in progress since Mon Jun  1 00:00:02 2015                       
        9.37T scanned out of 10.5T at 33.4M/s, 9h30m to go                     
        0 repaired, 89.58% done                                                
config:                                                                        
                                                                               
        NAME                                            STATE     READ WRITE CKS
UM                                                                             
        TrainData                                       ONLINE       0     0   
0                                                                             
          raidz1-0                                      ONLINE       0     0   
0                                                                             
            gptid/e8bd8d19-8558-11e2-8829-08606ecff386  ONLINE       0     0   
0                                                                             
            gptid/de759034-f30e-11e2-be11-08606ecff386  ONLINE       0     0   
0                                                                             
            gptid/e9830e2e-8558-11e2-8829-08606ecff386  ONLINE       0     0   
0                                                                             
            gptid/e9ed7158-8558-11e2-8829-08606ecff386  ONLINE       0     0   
0                                                                             
            gptid/ea50fab4-8558-11e2-8829-08606ecff386  ONLINE       0     0   
0                                                                             
                                                                               
errors: No known data errors

Any thoughts on what to look for when this scrub finally finishes later today? Is this possibly signs of a drive starting to go south on me? Thanks again guys!

 

[Jailer]

Yeah you've filled your pool up with data. Performance tanks when you do this as you've discovered.

 

[Fattrain]

Wowza! So 20% free space is considered a "full pool" ? Well that sucks, time to start planning out a bigger data rig I guess :-(

 

[HoneyBadger]

Plan for one with ECC support as well if you care about that data. If it's just downloaded/ripped music and video, then it's up to you how much you care.

 

[Robert Trevellyan]

Any thoughts on what to look for when this scrub finally finishes later today? Is this possibly signs of a drive starting to go south on me? Thanks again guys!

Check SMART data on all your drives, especially attribute #5. Lots of reallocated sectors would kill performance.