I started off with a single drive in my EX4100 to play around with it while I waited to get three additional drives. I have inserted the three additional drives and started a migration from JBOD to RAID 5. I am a few hours in and the Web Interface status says I am at 0.9% with 8116 minutes remaining…what? This is almost a week. I looked through the forum and found how to use mdstat in SSH. It is showing 18.9% complete with 701 minutes remaining. This is much more palatable to me. However, which one is correct? Are there other actions required that the Web Interface knows about that the mdstat doesn’t? I would have to imagine the Web Interface is only using data it gets from the call commands it uses from the system and doesn’t have the brain to do it on its own. Any ideas or experience others have had looking at this?
Update: 13 hours into process and Web says 3.8% complete with 7735 minutes remaining. The mdstat says 75.3% complete with 290 minutes remaining. hopefully it will all be done today?
The mdstat is also a little wonky:it shows 2 of my drives as spare and a 2/1 configuration for required devices versus used devices. Is this just part of the process and will go to 4/4 when complete? It also shows the first drive as up and second as down.
The rebuild times may speed up a bit if you have a ply with the settings described in tip #1 at the link I have pasted. I’ve done this before myself and it has helped.
https://www.cyberciti.biz/tips/linux-raid-increase-resync-rebuild-speed.html
As for migrating from one RAID type to another, I’ve had no success with it. I tried migrating from a RAID 1 (2 disk) to a RAID 5 (4 disk) and could not get the feature working properly and in the end backed up my data elsewhere and then recreated the RAID 5 from scratch and restored.
JediNite
Yeah…I saw all that info about building from scratch rather than migrating in the forums AFTER I started. All my data was already off of it…I should have gone that route. So now I am about 22-23 hours in and the mdstat command says it is reshaping everything (before was resync I think…or it might have been recovery…I can’t remember). Now the mdstat time matches the Web Interface (DashBoard) time. It is at 3416 minutes left…2.5 days? WOW. I hope if a drive fails the actual rebuild process is faster. The mdstat is now showing the expected device availability of 4/4 and all devices up now.
What issues did you have with your migration so I know what to look out for? How much faster is a from scratch RAID configuration versus a migration so I know for next time (if mine migrates correctly)?
Thanks for the link. I’ll look at it. Can I make any changes while the build is going or should I wait until it is done for next time?
Bob
You should be right to make the changes while it is doing it’s thing.
As for the time it took, I basically did a few rsync backups before I started anything to another NAS. Although it did not have sufficient space so had to select some stuff to lose. 
When it started to not go to plan, I basically, rebooted the NAS and then removed the RAID via the GUI and rebuilt it the way I wanted. Then had to manually recreate my shares and then rsync copy the stuff back to the WD EX4100. The other NAS I had was quite slow so took a few days to get all the content back on.
You may have more luck then I as I have seen others report on these forums they were able to migrate their RAID to a different type successfully, so maybe I was just unlucky. I would suggest making the changes and see if that speeds up your “reshaping time”. and if everything checks out okay at the end then great. Otherwise you will need to plan to rebuild from scratch.
Forgot to add, the issues I had were pretty much when all the process had finished to migrate my RAID 1 to RAID5, the available space on the RAID did not change and the personalty still indicated it was running in RAID1 rather then RAID 5. This was checked with “df -k” and “cat /proc/mdstat” via SSH.
Cheers,
JediNite
Mine is already showing RAID 5 in mdstat while in reshape, so hopefully it is going to plan. GUI still shows only 7+TB free space (I started with 1x8TB and expanding to 4x8TB)…I am assuming that will not change to show full allocated space until the process is done.
I tried to increase the speeds. It did not change anything. I am at ~36M/s, and I guess that is somewhat good in comparing it to other speeds I have seen in forums.
All my data is already on multiple external drives that were filling up…I should have just built a fresh volume at the beginning instead of migrating it. I did have a little bit of data I had copied over to play with it and learn with that I thought I would keep if it would migrate, but maybe it would have been quicker to just re-copy it.
Thanks for all the insight! I’ll just wait it out at this point (2.5 days) and see where I end up. Hopefully this lasts me for a lot of time. I went big so I wouldn’t have to do this again for a while!
Good luck. Hope you don’t lose power while this is all going on as this can corrupt the RAID volumes beyond repair (apparently).
I’ll periodically add to this so others can have a sense of what to expect if they are doing the same on their unit.
I am now ~38 hours in and the reshape is at ~25% and still at ~2.5 days remaining. It looks like things slowed down overnight as I am now at ~25 M/s (even with the speeds changed from JediNite’s link).
The Dashboard is still tracking with the mdstat for time remaining. I’ll keep waiting it out!
The speed consistently slowed down to ~17M/s making me think it was never going to finish. I just checked it and it is now at ~126M/s showing about 11 hours to complete (34% complete at this point). I am about 48 hours into the migration at this point. Did it slow down while it was migrating my data and now it is complete with my data so it is just filling out the space which makes it go faster now? I am baffled at this point…new to this RAID stuff, so I guess this is exciting I am learning something new.
Final post for any that read:
It finished while I was at work. According to logs, it looks like it took a total of just about 60 hours to migrate a 1x8TB JBOD with 700Gb or so of data on it to a 4x8TB RAID 5. The Dashboard shows a healthy RAID 5 with ~23+TB of free space. The mdstat in SSH shows a healthy RAID 5 and the df -k shows plenty of room available on my volume.
Thank God that’s done…now I get to move my 9+TB of data I have on all sorts of drives onto this thing…YAY!
Glad it worked for you 
