Changes to the Primary File System in Cisco IOS XE 17.10.1

From Cisco IOS XE 17.10.1, the flash file system on IE switches is the primary file system for booting an IE switch, regardless of whether an SD card is present. The primary file system can no longer be configured. If the IE switch cannot find a configuration in flash, it will attempt to find one in sdflash, then copy the configuration and IOS XE image to flash, and boot from flash as described in the following section.

The sync command after 17.10.1 works only in on direction - from flash to sdflash - as the sync from sdflash to flash is an automated process.

Swap Drive

The Swap Drive feature allows you to use SD card as a backup for the startup configuration and the IOS XE .bin or install file. You can remove the SD card from one IE switch and install into a new IE switch. When the new IE switch (without a startup configuration in flash) is powered on, it checks flash for a configuration file. If the file is not found, the switch looks for a configuration file in the sdflash. If found, it:

• automatically copies the startup configuration and IOS XE files from sdflash to flash

• automatically reboots, and

• boots with the copied files from the previous IE switch.

Booting the Switch from Flash or an SD Card

Prior to Cisco IOS XE 17.10.1, the switch could boot from either its internal flash memory or an SD card, with the SD card taking precedence. If an SD card was installed, the switch attempted to boot in the following order:

1. From the Cisco IOS-XE image that is specified in the boot path.

2. From the Cisco IOS-XE image in the SD card.

3. From the Cisco IOS-XE image in the internal flash.

SD Card Support, Formatting Options, and Usage Considerations

• The switch does not support third-party SD cards or SD High Capacity (SDHC) cards. Attempting to use a non-supported card results in the following message being displayed:

  WARNING: Non-IT SD flash detected.
  Use of this card during normal operation can impact and
  severely degrade performance of the system.
  Please use supported SD flash cards only. 

• If the write-protect switch on the SD card is in the lock position, the switch can read data on the card and boot from the card. However, updates and files cannot be written to the card.

Inserting an SD Card into the Switch

1. Ensure the SD card is oriented correctly.

2. Gently press the SD card into the SD card slot on the switch until it clicks into place.

When an SD card is inserted, the system logs a syslog message similar to:

 Mar 30 01:38:51.965: %FLASH-6-DEVICE_INSERTED: Flash device inserted 

Removing an SD Card from the Switch

1. Press the SD card inward slightly to release it.

2. Once it ejects, pull the card straight out of the slot.

When an SD card is removed, the system logs a syslog message similar to:

 Mar 30 01:39:12.467: %FLASH-1-DEVICE_REMOVED: Flash device removed 

Hot-Swappable Behavior

• The SD card is hot-swappable—it can be inserted or removed while Cisco IOS XE is running.

• Do not remove the SD card during the boot process or when a write operation to sdflash is in progress.

Boot Loader Commands

The following boot loader commands can be executed on an SD card:

• boot—Load and boot an executable Cisco IOS XE image

• cat—Concatenate (type) a file or files

• copy—Copy a file

• dir—List files in directories

• fsck—Check file system consistency

• format—Format a file system

• mkdir—Create directories

• more—Concatenate (display) file

• rename—Rename a file

• rmdir—Delete empty directories

• sd_init—Initialize SD flash file systems

How Commands Work with SD Cards

When an SD card is installed in the switch, the write, boot, and sync commands behave as described below.

write Command

The write command saves the running configuration. See the table below for command behavior details.

boot Command

The boot command lets you change the system boot parameters. See the table below for command behavior details.

sync Command

The sync command copies the Cisco IOS-XE image directory, configuration files, and boot parameters from the internal flash memory to the SD card. Prior to 17.10.1, you could copy from the SD card to the internal flash memory as well.

Prior to 17.10.1

After copying the files, the sync command verifies whether the Cisco IOS-XE image is appropriate for the switch model and that sufficient destination flash memory is available. If a potential issue is detected, the sync process is aborted.

When the verification is successful, the sync command retrieves the files from the SD card and overwrites the destination Cisco IOS-XE image directory and configuration files. By default, the sync command overwrites the destination files. However, there is an option to save the old files, overriding this default behavior.

Note	If the running configuration has not been saved before running the sync command, the switch prompts you to save the running configuration before proceeding.

SD Card Alarms

The SD card alarms notify users of potential issues related to the SD card. See the table below for alarm details.

By default, the SD card alarms are disabled. To activate the alarms, use the options of the alarm facility sd-card global configuration command. Additionally, you can configure the alarms and associated traps to be sent to syslog and the SNMP server.

Note	To disable the alarm, use the following commands: no alarm facility sd-card enable— disables the alarm facility enabled for the SD card. clear facility-alarm—clears the alarm warning state for the alarms configured on the switch.