USB 3.0 SSD
From Cisco IOS XE Fuji 16.9.1, support for USB 3.0 SSD is enabled on Cisco Catalyst 9300 Series Switches. USB 3.0 SSD provides extra 120 GB storage for application hosting. Applications can be hosted in Kernel Virtual Machines (KVM), Linux Containers (LXC ), or Docker containers. The storage drive can also be used to save packet captures, trace logs generated by the operating system and third-party applications. USB 3.0 SSD can be used simultaneously as a general-purpose storage device and as an application-hosting device. You must use only Cisco USB drives; non-Cisco USB drives are not supported.
USB 3.0 SSD cannot be used to boot images, emergency install the images, or upgrade internal flash using (software maintenance update (SMU or install commands. Bootloader support for USB 3.0 SSD is not available.
USB 3.0 SSD is enabled with Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T) functionality for health monitoring of the drive. The purpose of S.M.A.R.T is to monitor the reliability of the drive and predict drive failures, and to carry out different types of drive self tests. SMART Disk Monitoring Daemon (smartd) is enabled immediately after the insertion of a USB 3.0 SSD and starts logging warnings and errors in the /crashinfo/tracelogs/smart_errors.log. These warnings and errors are also displayed on the console. On removing the USB 3.0 SSD, smartd stops running.
USB 3.0 SSD is supported as a field-replaceable unit (FRU) that offers flexible storage configurations. If SSD is used initially on a PC, the default partition on USB 3.0 SSD is created by the PC supporting all the file systems. If SSD is used initially on the switch, one partition of 120 GB is created to support EXT4 file system.