[Gluster-devel] gluster, gfs, ocfs2, and lustre (lustre.org)

[gordan at bobich.net]

On Fri, 2 May 2008, gordan at bobich.net wrote:

> On Fri, 2 May 2008, Shaofeng Yang wrote:
>
>> Can anybody share some thoughts about those cluster file systems? We are
>> trying to compare the pros and cons for each solution.
>
> GFS: Shared storage FS. Integrated with RHCS.
>
> OCFS2: Shared storage FS, very similar to GFS. Standalone. Fencing/failover 
> has to be provided by something like RHCS or Heartbeat.

I should probably stress that the above are for SAN based operation, but 
logically this extends to operating on top of a mirrored network block 
device like DRBD.

> Lustre: Advanced network file system. Despite claims of great scalability, 
> metadata storage failover/redundant, but not load-shared.
>
> GlusterFS: Replicated network FS with POSIX locking and support for file 
> based striping and mirroring. Required xattr support on the backing file 
> system, but files are the same on the exported and underlying file systems, 
> which makes data recovery very straightforward and sensible if anything goes 
> wrong.
>
> Depending on what you plan to use it for, you may also want to look into 
> Coda: replicated FS, supports disconnected operation through caching. 
> Permission system can take some getting used to because they are based on 
> external ACLs rather than owner/group/other permissions as per standard UNIX 
> paradigm. Limited to 1000-4000 files per directory.

These three are client-server based FS-es (there is nothing stopping a 
client from also being a server). GlusterFS and Coda both store files raw 
on the underlying file system. Coda has it's internal metadata stores 
(files are stored with original content, but names are just numbers), 
whereas GlusterFS uses xattrs for metadata and file names are as original.

Gordan