Sometimes it's adviced to increase the blocksize on a device to achieve a better performance. This can be done in the Advanced Options for the device. As always: do not forget to click the "Apply" button to save the changes.

Now once this is done, will the tapes which were written with a lower block size still be readable for restore? The answer is: yes! A device with a higher block size will be able to read the lower block size tapes. The other way around, it would not be possible. A device with a lower block size won't be able to read higher block size tapes.

So, reading was backward compatible after increasing the block size. Now. appending to a lower block size tape using a higher block size device will fail. It is recommendable to create a new pool to store the lower block size tapes until the data on them is expiring. Once expired, the tape can be reformatted with the higher block size device and moved to the original pool again.

You may be interested to some of my other Support Tips too: Support Tips listed per category.