The Oracle Server X5-2L Installation Guide for Oracle Solaris Operating System (E48328-03), that is published on the Oracle Documentation web site, incorrectly states that NVMe drives should not be used as installation targets in the "Installation Target Options" section of the guide. The correct information for the first paragraph of this section is the following:
You can install the operating system on any of the storage drives installed in the server. Hard disk drives (HDDs), solid state drives (SSDs), NVMe Express (NVMe) storage drives, and RAID volumes are valid installation targets for Oracle Solaris OS.
The Note about NVMe drives is incorrect and should be disregarded.