Datasets and Zvols list different compression levels
Compression should not be a static list but rather a variable so that every place that uses it will be consistent and updated when compression levels change. And yes, proper use of capitalization is needed :-)
In the new UI:
1. Dataset compression options are: OFF, LZ4, GZIP-1, GZIP-6, GZIP-9, ZLE
2. Zvol compression options are: Inherent, Off, lz4 (recommended), gzip (default level, 6), gzip (fastest), gzip (maximum, slow)
This needs to be sorted in time for 11.2 (preferably BETA1) as it is holding up the Guide.