When mixing different generations of LTO drives and media, you need to consider the read-write capabilities of each generation. As a best practice, configure a different device class for each generation of media.
| Drives | Generation 1 media | Generation 2 media | Generation 3 media | Generation 4 media | Generation 5 media |
|---|---|---|---|---|---|
| Generation 1 | Read and write | n/a | n/a | n/a | n/a |
| Generation 2 | Read and write | Read and write | n/a | n/a | n/a |
| Generation 3 | Read only | Read and write | Read and write | n/a | n/a |
| Generation 4 | n/a | Read only | Read and write | Read and write | Read and write |
| Generation 5 | n/a | n/a | Read only | Read and write | Read and write |
If you are mixing different types of drives and media, configure different device classes: one for each type of media. To specify the exact media type, use the FORMAT parameter in each of the device class definitions. (Do not specify FORMAT=DRIVE). For example, if you are mixing Ultrium Generation 1 and Ultrium Generation 2 drives, specify FORMAT=ULTRIUMC (or ULTRIUM) for the Ultrium Generation 1 device class, and FORMAT=ULTRIUM2C (or ULTRIUM2) for the Ultrium Generation 2 device class.
Both device classes can point to the same library in which there can be Ultrium Generation 1 and Ultrium Generation 2 drives. The drives will be shared between the two storage pools. One storage pool will use the first device class and Ultrium Generation 1 media exclusively. The other storage pool will use the second device class and Ultrium Generation 2 media exclusively. Because the two storage pools share a single library, Ultrium Generation 1 media can be mounted on Ultrium Generation 2 drives as they become available during mount point processing.