My main bulk storage for the home LAN is a bank of 4TB drives, set up in a large RAID6 array. Due to a brownout this evening on the +12v supply for one of the disk banks, I’ve had to start rebuilding two of the disks.
![Core NAS](http://www.experimental-engineering.co.uk/wp-content/uploads/2015/10/IMG_20151014_224439-e1444916668164-225x300.jpg)
The total array size is 28TB after parity – 9 4TB disks in total. The disks are connected through USB3 to the file server.
![mdadm Detail](http://www.experimental-engineering.co.uk/wp-content/uploads/2015/11/Screenshot-from-2015-11-19-222514-300x234.png)
Here’s the current status of the array. Two of the disks decided that they wouldn’t rejoin the array, so they got their superblocks cleared & readded manually. This forced the array into rebuilding.
![Rebuild Progress](http://www.experimental-engineering.co.uk/wp-content/uploads/2015/11/Screenshot-from-2015-11-19-223633-300x234.png)
Rebuilding an array of this size takes a while, as can be seen from the image above, it’s going to take about 7200 minutes, or 5.2 days.