So, long story short, I have spent the last week or so moving data off array disks, reformating some old drives from Reiserfs to XFS and moving the data back. Because I had 16 array drives and a buttload of data to move around, I disabled my 2 parity drives and used them in unassigned devices to store data while doing this.

 

While in this process, I have noticed that one of my array drives is VERY slow (maybe 10-15MB/s) while every other drive gets copied to at about 183MB/s (with parity disabled).

 

Usually, if I wanted to swap a drive out I would replace it and let parity rebuild it, however with them currently disabled I wanted to know if I can install a new drive, use new config to swap it in the array, and mount the old drive using unassigned devices to copy the data back. I have tried, and the drive is slowing parity rebuild times so I thought this might be a more efficient way to go about this.

 

Obviously I have all VMs and dockers disabled while doing this to ensure nothing else is writing to the array.

 

So, is this something I can do?

It's not a problem mounting an array disk in UD, of course if the data fails to copy due to read errors in case the disk really fails there won't be much you can do.

all good, I figure I have a higher chance of the disk failing while building parity seeing as it would read 100% of the drive.

 

Thanks, ill give it a try