Hello,

 

I'm planning to migrate from DriveBender to Unraid and have a few questions I'm hoping I could get some help on...

I'm running running NAS with DriveBender in mirrored setup on Server 2012 R2 with about 15TB of actual contents mirrored for total of 30TB.  

I want to re-use this NAS server as the Unraid and migrate all existing contents from DriveBender pool.  I'm currently considering doing it in following steps...

1. In DriveBender,
   • disable mirror mode and delete all duplicate files.  This will leave files scattered across 12 of the HDDs. 
   • Remove all HDDs from DriveBender except for 5x 4TB drives to force DriveBender to consolidate all files to only these 5 drives. 
2. Move the 5x 4TB HDDs to another server and restore the DriveBender pool (this is so I can still access the contents for a few days while I rebuild the existing NAS server as unraid). 
3. Install Unraid to the NAS server and create an unraid array using the 7 extra HDDs I recovered from consolidating DriveBender files from step 1. 
4. Copy all files from DriveBender pool I restored from Step 2 to the new Unraid array via SMB or via Unassigned Devices Plugin. 

 

I think the above steps will work.. although step 4 will take quite a bit of time.. 

 

Here are my questions:

• In step 3 when I create the unraid array, is it better to create the array with Parity disk or should I add the parity disk after all the files have been copied from Step 4? The reason I ask is because I'm concerned that by adding the parity disk first that my write speed will be impacted thus severely impacting the total time it takes to copy the data. Is it even possible to add a parity disk after the fact?
• Are there any issues with the steps I've outlined above? 

 

Thank you!

8 minutes ago, nitewolfgtr said:

Is it even possible to add a parity disk after the fact?

 

Yes, but you can also enable turbo write for the initial copy.

 

 

19 hours ago, johnnie.black said:

 

Yes, but you can also enable turbo write for the initial copy.

 

 

Awesome! I did not realize that feature existed. Is it fair to say that Write speed for array with no-parity drive vs array with parity mode set to turbo write are about equal? 

1 minute ago, nitewolfgtr said:

Awesome! I did not realize that feature existed. Is it fair to say that Write speed for array with no-parity drive vs array with parity mode set to turbo write are about equal? 

 

As long as all disks have similar performance and there are no controller/bus bottlenecks the write speed with turbo write will be the same as writing to a paritless array, if there are slower disks it will be limited by these.

 

Parity check speed is a very good indication of the max turbo write speed, it can never be faster than that at any point.

Since I just posted this screen on another thread I'll posted here also as an example of Turbo Write, 8 disk array of mostly 8TB Seagate Archive drives (note: these speeds are only possible when writing to the start of a disk, speed decreases from ~190MB/s to ~100MB/s as you move through the inner slower tracks)

If you copy via SMB and assuming you have modern hard drives, unless you have 10Gb networking the network can be the gating factor.  Here's a copy where I turned on Turbo Write in the middle - you can see that it scaled right up to 1Gb max throughput.