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The ADvanced Systems Laboratory (ADSL)

Optimistic File System


You can download the source tarball here. It contains the modified Linux 3.2 kernel and the OptFS file-system module. Instructions for compiling and loading the module can be found inside the tarball.


You can also browse the source code at our Github repository.


The OptFS file-system module is modified on top of ext4 and jbd2. It contains the code of both ext4 and jbd2. Diffing this against just ext4 will result in a lot of redundant lines in the patch. Hence we have roughly merged ext4 and jbd2 into a module, and diffed OptFS against this. This patch is presented as optfs_patch_educational.

Note that optfs_patch_educational should never be applied to an actual system: this will not work. It is provided so that users can easily view the differences in code between OptFS and ext4, and is not meant to be applied directly.


We provide a Virtual Machine with all dependencies and OptFS installed and properly configured. With this version, you can simply open the virtual machine and start trying out OptFS!

Click here to download the VM: 4.1 GB VM tar.

Open this virtual machine with VMWare. The username is root, and the password is password. Please follow the instructions in README to try out OptFS.