ASMFS

A read-only FUSE filesystem that exposes Oracle ASM files.

⚠️ This project is experimental, not well-tested, and still under development.

Compile

$ cargo build

Help

Usage: asmfs [OPTIONS] <MOUNT_POINT>

Arguments:
  <MOUNT_POINT>  Act as a client, and mount FUSE at given path

Options:
      --conn <CONNECTION_STRING>  Connection string to remote ASM instance - user/pass@host:port/service (user must have sysdba)
      --no-raw                    Use DBMS_DISKGROUP.READ() instead of raw device access
      --mirror <mirror>           0=>primary copy, 1=>first redundant copy, 2=>second redundant copy [default: 0]
      --auto-unmount              Automatically unmount on process exit
      --allow-root                Allow root user to access filesystem
  -h, --help                      Print help
  -V, --version                   Print version

Two Modes

There are two different implementations on how asmfs can read files from ASM:

• A raw access to block devices, which is the default and works as described here (link todo).
• dbms_diskgroup.read() which is used only if you explicitly specify --no-raw. The limitations of this approach are described in this blog post

Installation

Grab one of the .rpm files from asmfs releases and simply run:

dnf install ./asmfs-VERSION.x86_64.rpm

Examples

Raw mode with udev

Run under grid user:

/opt/asmfs/asmfs /mnt/asmfs/

Raw mode with AFD

Run under root user (because otherwise AFD won't allow non-oracle I/O to ASM disks):

/opt/asmfs/asmfs --conn username/password@db-server:1521/+ASM /mnt/asmfs/

(such username can be created on +ASM instance with CREATE USER syntax. Such user must also be granted at lease SYSDBA privilege.)

dbms_diskgroup.read locally

$ . oraenv
ORACLE_SID = [+ASM] ? +ASM

$ /opt/asmfs/asmfs/asmfs --no-raw /mnt/asmfs/

dbms_diskgroup.read remotely

$ /opt/asmfs/asmfs/asmfs --no-raw --conn user/pass@hostname:1521/+ASM /mnt/asmfs/

Umounting

fusermount3 -u /mnt/asmfs/

Debugging

If you run into issues, you can find out more about what's going on by setting those env vars:

RUST_BACKTRACE=1 RUST_LOG=info /opt/asmfs/asmfs ...

Warning!

This is not meant for production usage.

This project is experimental, not well-tested, and still under development.

Contributions are welcome! Ideas, issues, and pull requests are appreciated.

Screenshot (demo)