Change the RAID Type of a Storage Pool
Storage pools can be changed from one RAID type to another without losing existing data. For example, you can create a RAID 1 storage pool on your DiskStation and later change it to RAID 5 if you install more drives. This article provides instructions on changing the RAID type of existing storage pools on your DiskStation. Before you start changing the RAID type of a storage pool, please refer to the Drive Requirements and RAID Type Requirements and Limitations sections below for details on the relevant requirements and limitations.
Drive Requirements
To change the RAID type of a storage pool, you must have a sufficient number of available drives installed in your DiskStation. Please refer to the table below for the minimum number of drives required for each RAID type.
RAID Type |
Minimum Number of Drives Required |
RAID 1 |
2 |
RAID 5 |
3 |
RAID 6 |
4 |
SHR-2 |
4 or 5 (depending on the drive configuration of SHR-1) |
RAID Type Requirements and Limitations
Only certain RAID types can be changed to other RAID types. For example, RAID 1 can be changed to RAID 5, but RAID 5 cannot be changed to RAID 1. Please refer to the table below for details.
Current RAID Type |
Possible Conversion Target Type |
Additional Number of Drives Required |
Basic |
RAID 1 |
1 |
Basic |
RAID 5 |
2 |
RAID 1 |
RAID 5 |
1 |
RAID 5 |
RAID 6 |
1 |
SHR-1 |
SHR-2 |
1 or 2 (depending on the drive configuration of SHR) |
Note:
- For more information on SHR (Synology Hybrid RAID), please refer to this article.
- For more information on choosing the RAID type for a storage pool, please refer to this article.
- For an estimate of space utilization, please refer to Synology RAID Calculator.
- An SHR-1 storage pool with the following drive configurations may require two additional drives when changed to an SHR-2 storage pool:
- The storage pool contains only two drives.
- All drives have different capacities.
- In a RAID Array comprising three or more drives, the capacity of the two largest drives is larger than that of the other drives.
- Some DiskStation models do not support changing a RAID 5 storage pool to a RAID 6 storage pool.
- Some DiskStation models do not support changing RAID types when the storage pool contains drives that are not on the Synology Products Compatibility List.
Change the RAID Type
Before you start:
Before changing the RAID type, please note the following:
- Make sure the status of your storage pool is Healthy.
- When adding new drives to a storage pool, the new drives must be larger than or equal to the smallest drive in the storage pool and all drives must be of the same drive type.
- The RAID type of RAID Arrays in a RAID Group cannot be changed. The RAID Group feature is available on specific models only. Please refer to this article for more information.
Note:
- We recommend using drives in the Synology Products Compatibility List to prevent any issues. Using incompatible drives may affect the system performance and even result in data loss.
To change the RAID type of a storage pool:
- Launch Storage Manager.
- Go to Storage Pool.
- Select the storage pool that you want to change its RAID type, and click Change RAID Type from the Action drop-down menu.
- Select the RAID type that you want to change to. Click Next.
- Select the drives to add to the existing storage pool. Click Next.
Note: All data on the newly added drives will be erased. Please make sure to back up your data in advance.
- Follow the wizard to finish.