RAID-Z improvements and cloud device support

Solaris 11.4 introduced few new ZFS pool versions with interesting new features or enhancements:

# zpool upgrade -v
...
 38  Xcopy with encryption
 39  Resilver restart enhancements
 40  New deduplication support
 41  Asynchronous dataset destroy
 42  Reguid: ability to change the pool guid
 43  RAID-Z improvements and cloud device support
 44  Device removal
...

The RAID-Z improvements mean that data is written more efficiently - in some cases it can now store more data in a pool than before. But even more importantly the performance (both throughput and IOPS) of RAIDZ is now close to RAID10!

Spectre and Kernel Modules

On Linux one needs to recompile kernel modules to get protection, while on Solaris this is not necessary. Once you are on Solaris 11.4 with Spectre fixes enabled, all kernel modules, even compiled on older Solaris releases, just work and are protected. Nothing special to do there.