Overview: startup parameters and environment variables of VFS
VFS program startup parameters
-l <entry in fstab format>
The startup parameter
-l
mounts the defined file system.-f <path to fstab file>
The parameter
-f
mounts the file systems specified in thefstab
file. If theUNMAP_ROMFS
environment variable is not defined, thefstab
file will be sought in the ROMFS image. If theUNMAP_ROMFS
environment variable is defined, thefstab
file will be sought in the file system defined through theROOTFS
environment variable.
Examples of using VFS program startup parameters
Environment variables of the VFS program
UNMAP_ROMFS
If the
UNMAP_ROMFS
environment variable is defined, the ROMFS image will be deleted from memory. This helps conserve memory. When using the startup parameter-f
, it also provides the capability to search for thefstab
file in the file system defined through theROOTFS
environment variable instead of searching the ROMFS image.ROOTFS = <entry in fstab format>
The
ROOTFS
environment variable mounts the defined file system to the root directory. When using the startup parameter-f
, a combination of theROOTFS
andUNMAP_ROMFS
environment variables provides the capability to search for thefstab
file in the file system defined through theROOTFS
environment variable instead of searching the ROMFS image.VFS_CLIENT_MAX_THREADS
The
VFS_CLIENT_MAX_THREADS
environment variable redefines the SDK configuration parameterVFS_CLIENT_MAX_THREADS
._VFS_NETWORK_BACKEND=<VFS backend name>:<name of the IPC channel to the VFS process>
The
_VFS_NETWORK_BACKEND
environment variable defines the VFS backend for working with the network stack. You can specify the name of the standard VFS backend:client
(for a program that runs in the context of a client process),server
(for a VFS program that runs in the context of a server process) orlocal
, and the name of a custom VFS backend. If thelocal
VFS backend is used, the name of the IPC channel is not specified (_VFS_NETWORK_BACKEND=local:
). You can specify more than one IPC channel by separating them with a comma._VFS_FILESYSTEM_BACKEND=<VFS backend name>:<name of the IPC channel to the VFS process>
The
_VFS_FILESYSTEM_BACKEND
environment variable defines the VFS backend for working with file systems. The name of the VFS backend and the name of the IPC channel to the VFS process are defined the same way as they are defined in the_VFS_NETWORK_BACKEND
environment variable.
Default values for startup parameters and environment variables of VFS
For the VfsRamFs
executable file:
For the VfsSdCardFs
executable file:
For the VfsNet
executable file: