Slow Rebuild - Is this a Problem?

[MrMKHR]

Hi Guys,

 

might be obvious to most, but I'm not sure on it and couldn't verify via the board search:

I have a really mixed setup running. each drive from a different series. 4TB parity, 1x 1TB, 1x2TB, 2x3TB.

Yesterday I replaced the 1TB drive with a 4TB one.

 

The rebuild is running at ~35MB/s but before parity checks were running at 90MB/s. Now the question: Of course rebuild involves writing so it won't be as fast as a plain check, but is 90MB/s vs 35MB/s acceptable or is there a problem with the new drive?

Just want to check first before hunting for a problem that might not even exist in the first place...

 

Oh, just in case anyone needs it: the new drive is a WD40EURX. UnRAID 5.0, HP N54L (Turion DualCore 2.2Ghz)

[BobPhoenix]

Seems slow to me.  I get about the same speed rebuilding as doing a parity check. 

• Did you run some preclears on the drive before you started to rebuild on it to test it? 
  
• Did you backup your config folder on your flash drive before you started your rebuild? 
  
• Can you post a smart report of the new drive?
  
• Can you post a system log?
  

[MrMKHR]

1) sorry, no preclear. fresh from the package into the unraid box and added to the array. of course i can run some tests now.

2) not _directly_ before, but i always do a backup after i do modifications so the previous backup has the old config.

3 and 4) see attachments.

 

thanks for the help.

logs.zip

[BobPhoenix]

1) sorry, no preclear. fresh from the package into the unraid box and added to the array. of course i can run some tests now.

2) not _directly_ before, but i always do a backup after i do modifications so the previous backup has the old config.

3 and 4) see attachments.

 

thanks for the help.

I would suggest at least next time to run preclears on the disks first.  If this is a disk problem do you really want to trust your data to a possibly faulty drive?  Preclear helps find drives that will prematurely die.  An alternative would be the diagnostic programs provided by the manufacturers.  Or another that I've heard about: badblocks.

 

 

The smart report looks fine as far as I can tell.  Also I see nothing in the system log to indicate any problems AFTER the rebuild started.  Before that I really can't say as I'm not the best one to be reading it.  But after you started the rebuild I can comfortably say there doesn't appear to be anything wrong.

 

 

Now what I think might be causing it:  I would boot up in safe mode so all of your plugins are disabled to do the rebuild.  Also I notice you have simple features installed.  I would switch to Dynamix as that is more compatible with unRAID 5.0.  Simple Features has been reported to cause some problems with 5.0 that could be causing your slow rebuild due to screen updates.  Dynamix will allow the screen refresh to be turned off and that will likely speed up the rebuild.

 

 

But that is just my 2¢.  Someone else could have better advice.