RAID 5 + Spanning

Hi There!

I’m new to this community! but not new to WD NAS devices. I never had the opportunity to mix drives in a NAS before until I get one for home. I put my hands on a EX4100 and stuffed with 2 Purple 4TB and 2 Gold 2TB I had at home. I decided to create a RAID 5 to achieve performance and failure tolerance knowing I will loose 4TB. RAID 5 will use all drives at 2TB - 25% of all 4 drives so I got 6TB.

What I don’t understand, is why WD will allow one to create an spanning volume with the balance of the space? Wouldn’t that decrease performance? Is it save to do that for the underlaying RAID? More important, this space come from the 2 Purple 4TB, Why I can used that space at RAID 0 or 1?

Also, if you don’t create the Spanning volume while creating the RAID you will not be able to go back to it after.

Any ideas!!!???

This is to inform you that RAID 5 would stripe data and parity across three or more disks. In this RAID set, if a drive would fail, the data is automatically recreated from the parity and distributed data once the new drive is installed.

This RAID set is the most common for business servers and NAS devices. It will have good read performance but will have a hit performance on write speeds since the parity data needs to be recalculated with new data written on the drive. The size of about one of the drives will be lost in the RAID set in RAID 5.

Please refer to the link: How to Change the RAID Mode on a RAID Enabled My Cloud Device


I’m well aware of your indications and understand correctly all levels of RAID. What I don’t understand is why they allow you to create a spanning volume with the space not use for the RAID in my description.

If the system is capable of using the space regardless, it should automatically build a RAID 1 with the unused space and add the volume. The other option is to do something similar to their competitor and cut the hardware limitation and use just logical configuration, which is to treat everything as 6 logical drives of 2TB each and build the RAID.