The Problem: As I added files to my 6TB Mirror it started to get slower and slower, but worked without problems. Then - one day it went into ‘Rebuild’ mode and slowed completely - just as many other posts on this board talk about. I researched all those posts and tried many things. Eventually I planned an approach to try and get this think working. The Rebuild started and over 4 days went from start to 4.7%. About 2.5TB were on the drive at this time. Access to the Dashboard really annoyed me most, because I could not access to see anything or change anything.
Working Solution:The temperature of both drives was approaching 50C which had me very worried. So I placed a USB fan (6cm dia) pointing down into the drive. That immediately dropped the drive temps to 44-45 range and a slight increase in speed resulted. Lowering this fan with ambient temp of around 22C resulted in overnight temps of 42-42 on each drive.
By now I could access the Dashboard and starting shutting down the Mirror as follows:
-Auto Rebuild off
-Cloud Access States —disabled
-DLNAMedia Server – off
Public Sharing-- off
Media Sharing — off
User Access – off for everyone
WDSync - on only for admin
I then powered down (pulled plug) on the Mirror with great fear, then re-plugged it in and waited before accessing it on my iMac. It showed all the changes I made above, the drives were at 39C and 38C and I shut off the computer and went to bed (the Mirror is direct into the ISP router). The Rebuild was at 6.6%.
Result: Woke in the middle of the night, checked the Mirror, it was 45% Rebuild and the drives were 35-34C. All was good. Went to sleep and woke up this morning and the Rebuild it done, drives at 32-32C and works fast as ever.
- Get temperature of Mirror down - this is critical.
- Get the Mirror into a a position of Rebuild (this means taking it offline to others and cutting services). Appreciate that you want a short delay to rebuild (maintenance).
- Let it get a 100% Rebuild. Then switch on services.
I’ll let the community know what happens in the days ahead, if this works over time. I still do not know what triggered the rebuild. Or, when it will happen again. I wish the user could decide this alone. I think these Servers need more fan cooling capability.