Install the xattr utility tool:
apt install python-xattr
Assuming the root of the mergerfs filesystem is /storage, use xattrs to view the pseudo .mergerfs file:
cd /storage xattr -l .mergerfs
returns:
user.mergerfs.srcmounts: /mnt/data/disk01:/mnt/data/disk02:/mnt/data/disk03:/mnt/data/disk04:/mnt/data/disk05 user.mergerfs.minfreespace: 21474836480 user.mergerfs.moveonenospc: true user.mergerfs.policies: all,eplfs,eplus,epmfs,erofs,ff,lfs,lus,mfs,newest,rand user.mergerfs.version: 2.13.1 user.mergerfs.pid: 91089 user.mergerfs.category.action: all user.mergerfs.category.create: eplfs user.mergerfs.category.search: ff user.mergerfs.func.access: ff user.mergerfs.func.chmod: all user.mergerfs.func.chown: all user.mergerfs.func.create: eplfs user.mergerfs.func.getattr: ff user.mergerfs.func.getxattr: ff user.mergerfs.func.link: all user.mergerfs.func.listxattr: ff user.mergerfs.func.mkdir: eplfs user.mergerfs.func.mknod: eplfs user.mergerfs.func.open: ff user.mergerfs.func.readlink: ff user.mergerfs.func.removexattr: all user.mergerfs.func.rename: all user.mergerfs.func.rmdir: all user.mergerfs.func.setxattr: all user.mergerfs.func.symlink: eplfs user.mergerfs.func.truncate: all user.mergerfs.func.unlink: all user.mergerfs.func.utimens: all
NOTE: This shows that there are 5 disks in the pool, namely:
All of options shown can be set in real time without unmounting and re-mounting the mergerfs pool via the runtime options.
From within the root of the mergerfs filesystem (eg. /storage)
xattr -w user.mergerfs.srcmounts '-/mnt/data/disk05' .mergerfs or, for removing two disks use: xattr -w user.mergerfs.srcmounts '-/mnt/data/disk04:/mnt/data/disk05' .mergerfs
NOTE: This will remove disk04 and disk05 from the current srcmounts.
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From within the root of the mergerfs filesystem (eg. /storage)
xattr -w user.mergerfs.srcmounts '-/mnt/data/disk4/storage' .mergerfs
NOTE: xattr is a useful tool.
Use the following command to install it:
apt install python-xattr