XtreemFS 1.3.1 Available Now!

XtreemFS 1.3.1 is available now, which adds some minor features and fixes a wide range of bugs that were disclosed since the previous stable release.

Bug fixes mainly relate to the new client and the replication infrastructure. We included the following features:

• Metadata replication. Although XtreemFS 1.3.0 already provides some preliminary support for MRC and DIR replication, the feature turned out to be fairly unstable. With XtreemFS 1.3.1, we took a big step forward in this respect. Especially the MRC replication has been thoroughly tested now and offers automatic fail-over on the client side.
  
• Asynchronous writes. We enhanced the client with preliminary support for asynchronous writes. However, the feature is currently limited to non-replicated and failure-free scenarios, as it has not yet been integrated with the client's internal retry mechanism.
• Monitoring. We added a service monitoring infrastructure. It is based on SNMP and provides information about the internal state of an XtreemFS service, such as the current memory consumption, I/O throughput, the number of stored files, etc. We also added a corresponding Ganglia plug-in.
  
• OSD drain tool. We included a utility to remove OSDs from an XtreemFS installation. The tool relocates all files from the respective OSD to other OSDs and gracefully shuts down the OSD.
• Gentoo overlay. To simplify the use of XtreemFS for our Gentoo users, we added a Gentoo overlay for installing XtreemFS on Gentoo.

For a more detailed overview of the changes, please refer to our change log. We also updated the list of known issues and moved them to the issue tracker.

We further noticed that we caused some confusion with the 1.3.0 release, as it was sometimes referred to as a release candidate. The website as well as the servers and clients themselves always stated "1.3.0 RC1" as version. However, the packaging did not allow us to release a "1.3.0-RC1" version and therefore we ended up publishing "1.3.0" packages. Blogs and news websites also referred to the released version as "1.3.0". So, we'll leave it that way: XtreemFS version 1.3.0 RC1 is regarded as 1.3.0 and now we're releasing the next version, 1.3.1.

Since we released XtreemFS 1.3.0 in August, we got quite a lot of feedback on the mailing list - thanks a lot to our user community for consistently helping us to improve XtreemFS!

To be able to quickly respond to the needs of our users, we decided to establish a separate repository with unstable packages, which we update frequently. Unstable packages are less thoroughly tested than stable releases, but they allow us to fix bugs and provide new features on short notice. A link to the unstable repository can now be found on our website at http://www.xtreemfs.org/download.php#unstable.

Public XtreemFS demo server online again

Do you want to test XtreemFS without installing the servers first?

No problem! Just install the XtreemFS Client 1.3 (currently available for Linux and MacOSX, Windows will follow later) and mount our public XtreemFS demo server:

mkdir ~/xtreemfs_demo
mount.xtreemfs demo.xtreemfs.org/demo ~/xtreemfs_demo
cd ~/xtreemfs_demo

We placed a copy of the freely available short film "Big Buck Bunny" on the demo server which you can watch after mounting. (Please keep in mind that your Internet connection to our demo server has to be fast enough to watch it smoothly.)

For testing you can create any directories and files as you like. Please do not upload anything illegal or copyrighted material. For legal reasons every file create/write is logged with the IP address and timestamp. Files are automatically deleted every hour.

Upgrading from XtreemFS 1.2.x to 1.3

The good news is that the on-disk formats of the DIR, MRC and OSD haven't changed which means that just need to update the packages. The bad news is that 1.2.x and 1.3.0 are protocol-incompatible, you can't mix 1.2.x servers/clients with 1.3.0 servers/clients.

To upgrade servers, shut them down. Install the 1.3 packages (or update if you have the xtreemfs repository configured) and start the servers again. For the clients, unmount all mounted volumes and install (or update) the 1.3.0.

Most important changes in the user-interface:

• mount.xtreemfs has new command line options
• xtfs_stat, xtfs_repl and xtfs_sp have been merged into xtfsutil
• xtfsutil works on files on mounted volumes, not on URLs
• you can use xtfsutil --errors /mount/point to retrieve client error messages

First Release Candidate for XtreemFS 1.3

After nearly one year of development, we have finished the first release candidate for XtreemFS 1.3.
The most important new feature is the cross-site file replication with auto-failover. The new replication works with mutable files, i.e. files can be read and written.

We have created packages for Linux in our repositories on build.opensuse.org, they should become available within a few hours. For Mac OS X, we have a packaged client with installer. The sources can be downloaded at http://code.google.com/p/xtreemfs/downloads/list.

Moving towards 1.3

As you might have noticed, we are currently a full year behind schedule with the 1.3 release. The good news is that we are working heavily on the new release.

We now have a new client written from scratch that implements important features such a replica failover and metadata caching. The new client already passes our complete test suite (see http://groups.google.com/group/xtreemfs-test). Currently, we are cleaning up the code, work on a libxtreemfs, porting the client to windows and a lot of manual testing for the release.

Most of the changes we have worked on since last year are invisible to the user. First of all, we have switched the internal protocol to a custom RPC format which is optimized for transfer of raw data (the file content) and uses Google protocol buffers for message encoding. For this new RPC protocol, we have re-written and optimized the client and server infrastructure. The new protocol is up to 2x faster when transferring objects. As a user, you'll notice that the URLs now start with "pbrpc://" instead of "oncrpc://".

Over the next few weeks, we'll write short posts on the stuff we have been working, e.g. the PBRPC protocol, the new client features and internals, read/write replication for files, MRC replication ...
Of course, we'll keep you updated on the 1.3 release.

For anyone who wants to throw a first glance at XtreemFS 1.3, we set up a repository with unstable packages: http://download.opensuse.org/repositories/home:/xtreemfs:/unstable/
Please be aware that these packages are experimental and may be changed or updated without prior notice.