I recently purchased a second-hand EX4, and installed 4x 4TB Seagate Ironwolf disks in it. I selected to format it as a RAID 1, and was expecting to get one volume of 4TB of storage, with a fault tolerance of 3 disks. What I got instead was two volumes of 4TB each, with a total storage of 8TB.
This does not seem to be a true RAID 1 configuration. This seems to be either a RAID 01, or a RAID 10. Since there is already a RAID 10 option, I reckon it is a RAID 01. But in no way can this be a true RAID 1.
Please correct me if I’m wrong, as it seems that I can only be either very correct, or I can be very confused.
Hi, and thank you for your reply. Unfortunately I don’t see how this is related to the original question. I did not buy mine new; I bought it used and it came disk free. The four Seagate disks I installed myself, and they were brand new. No RAID configuration was pre-selected in my case, nor did I have any difficulty switching between RAID configs. My question has to do with the possibility that the RAID 1 that results from formatting the four drives that way seems more like a RAID 01, and I need to verify whether that is the case, or if I am being very wrong with what my expectations should be.
You are correct. What you have configured is not a true RAID 1 setup. RAID 1 is a mirroring configuration, which means that data is duplicated across all disks in the array. This provides fault tolerance, as if one disk fails, the data can be retrieved from the other disk.
However, what you have configured is a RAID 10 or RAID 01 configuration, which is a combination of RAID 1 and RAID 0. RAID 10 is a striped mirroring configuration, while RAID 01 is a mirrored striping configuration. In both cases, the data is duplicated across multiple disks for fault tolerance, but the data is also striped across the disks for improved performance.
In your case, it seems that the device is configured as a RAID 01, which means that the data is mirrored and then striped across the disks. This
