Data Redundancy and Drive Swapping with the Synology DS211+

How safe is your data once it’s on the DS211+.  I can compete with the best when it comes to destroying data.  I’m not going to pop a drive out and say wow, “the data is still on the other drive.”  Oh no, I’ve devised a crazy, real world, or perhaps un-real world, scenario that will test both the heartiness of this unit and my patience.

I’ve got two, 2TB drives in the DS211+.  I want to replace both of these drives with smaller drives without losing any data in the process.  The manual clearly states that if you lose/remove a drive you must replace it with a like size or larger drive.  If you don’t it will not give you a chance of rebuilding the mirror.  Even if you are using Synology’s SHR RAID with unlike drives.  Correct me if I’m wrong but I found it out first hand as well.

Here is how it started.  Synology Hybrid RAID with two 2TB drives.

Lets yanks a drive.

You can see in this screen shot that it’s not happy.  It also started to beep annoyingly to indicate it’s degraded state.  You can turn that beep off in this screen but it’s nice to know it will alert you if there is ever a problem.  There are also options to be notified via email and SMS.

In that first screen shot you can see it is requesting that I insert a new drive that is the same size or larger than the original.  I highly doubt that my scenario is recommended and I’m not sure why anyone would want to downsize the storage capacity in the unit but this should test the units ability to recover.  The goal is to insert a 1.5TB drive and recreate the volume and then remove the remaining 2TB drive and do the same.

I’m choosing the Create button in Storage Management.

SHR as I’ve done with the original 2TB volume.  Choose the new 1.5TB Disk 2 (shows up as 1.36 TB) and finish it up.

My data is still on the 2TB drive that is remaining.  I’ll copy the data from the 2TB drive to the 1.5TB drive.  Instead of an actual copy I’m going to Edit the share and change it’s location.  This is a nice feature and one I didn't count on during my scenario.

Share move in process.

Power off, pull the remaining 2GB drive out. Insert another 1.5TB drive and add the drive via Storage Manager.

Two happy 1.5TB hard drives configured in RAID.  I took this last screen shot after several days of use, backups, and reviewing.  I’ve not had a problem with volume at all.

I think this test was above and beyond a normal review of redundancy but it was nice to see that the unit is flexible enough to do something like this.  I’m not sure it will ever apply to the real world but I can see situations where you would have two 1TB drives in your Diskstation and you want to upgrade up to two 2TB drives.  It would be a little easier in this case because if you pull a 1TB drive and insert a 2TB in it’s place the RAID would rebuild without having to do share move process explained above.  As always, this is a “proceed at your own risk” situation.  I did it in a test environment with nothing to lose.