FUSE

FUSE (Filesystem in Userspace) can help you save Inodes in the filesystem.

Pros

  • store multiple files on one Inode

  • access times for small files may (although not necessarily) improve

Cons

  • it is writeable from only one node at a time (on other nodes it is read-only)

  • if content is modified then you have to re-mount on all other nodes

  • size of the image is predefined and space is allocated at creation

Create an image file with proper Lustre striping (i.e. over how many OSTs - object storage targets - should the image file be striped; see: Lustre performance considerations

lfs setstripe -c 2 ./store.img

Grow the image to have a size of 100 GB:

truncate --size=100G store.img

Create an EXT4 filesystem on the image:

mkfs.ext4 store.img

Note

If working with many small files, consider creating the filesystem with the -T small option.

Create a directory which will act as a mount point for the image:

mkdir store

Mounting for RW (read/write):

fuse2fs -o fakeroot,auto_unmount store.img store

Mounting for RO (read-only):

fuse2fs -o fakeroot,auto_unmount,ro store.img store

Unmount:

fusermount -u store

Checking available space / Inodes:

$ df -h store
Filesystem      Size  Used Avail Use% Mounted on
store.img        99G  573M   93G   1% /project/home/username/store

$ df -i store
Filesystem      Inodes IUsed   IFree IUse% Mounted on
store.img      6553600    11 6553589    1% /project/home/user/store