It is the file used to detect filesystems supported by the running kernel. You can quickly run grep command or cat command to display the list of all supported file system. nodev indicates that the file system is not associated with a physical device such as /dev/sdb1. If you see ext3 or vfat, it means you will be able to mount ext3 and vfat based file systems. This page explains filesystems supported by Linux using various commands.
How to see which filesystems are supported by the Linux
Following cat command will quickly tell you what filesystems supported by currently running Linux kernel:
$ cat /proc/filesystems
Sample outputs:
nodev sysfs nodev tmpfs nodev bdev nodev proc nodev cgroup nodev cgroup2 nodev cpuset nodev devtmpfs nodev configfs nodev debugfs nodev tracefs nodev securityfs nodev sockfs nodev bpf nodev pipefs nodev ramfs nodev hugetlbfs nodev devpts ext3 ext2 ext4 squashfs vfat nodev ecryptfs fuseblk nodev fuse nodev fusectl nodev efivarfs nodev mqueue nodev pstore btrfs nodev autofs xfs jfs msdos ntfs minix hfs hfsplus qnx4 ufs nodev zfs nodev binfmt_misc
Finding out Linux kernel modules
Type the following ls command to list the Linux kernel modules related to the filesystem:
ls /lib/modules/$(uname -r)/kernel/fs/*/*ko
Get a list of currently loaded Linux kernel modules
Run any one of the following commands:
cat /proc/modules
OR use the lsmod command along with grep command to filter out filesystems such as zfs:
lsmod lsmod | grep zfs
Sample outputs:
zfs 3604480 10 zunicode 331776 1 zfs zavl 16384 1 zfs icp 286720 1 zfs zlua 147456 1 zfs zcommon 86016 1 zfs znvpair 81920 2 zfs,zcommon spl 122880 5 zfs,icp,znvpair,zcommon,zavl
Please note that the lsmod is an awesome command which nicely formats the contents of the /proc/modules, showing what kernel modules are currently loaded.
How to load Linux kernel modules related to filesystem
Linux based systems comes with the modprobe command, to add and remove modules from the Linux Kernel. To load zfs module, run:
sudo modprobe zfs sudo modprobe -v zfs
