Overview
Starting from IOS XE 17.10.1, the flash:
file system on the IE switches is now the primary file system to boot the switch, regardless of an SD Card is present or
not. The sync command only works in one direction from flash:
to sdflash:
as there is no reason to sync from sdflash:
to flash:
and also because the sdflash:
is not the primary file system. Additionally, the primary file system can no longer be configured starting from 17.10.1.
Primary file system is fixed as flash:
.
Prior to IOS XE 17.10.1, the sdflash:
file system could be used as primary file system. if an SD Card was present, and it contained IOS XE bin or install file,
and the startup configuration it was used as the default. IE Switches running IOS XE older than 17.10.1 can still use either
sdflash:
or flash:
as primary file system, which the user can configure.
Even with the above changes, the SD card can still be used as part of Swap Drive feature. sdflash:
is always the backup for startup configuration and IOS XE bin or install file. The SD Card swap drive feature allows users
to remove SD Card from one IE Switch and install into a new IE switch. The new IE switch (with no startup configuration on
the flash:
because its new), will copy the startup configuration file and IOS XE file(s) from sdflash:
to flash:
and then reboot. Upon reboot, the new IE switch uses the copied files so it boots with configuration enabling to replace
the IE switch for which the SD Card was previously installed.
When an SD card is formatted on the switch, the card is formatted with the Disk Operating System Filing System (DosFs), a platform-independent industry-standard file system that is supported on various Cisco switches and routers.
The switch does not support third-party SD cards or SD High Capacity (SDHC) cards. Attempting to operate the switch with a nonsupported card causes the following message to be 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, but updates and files cannot be written to the card.