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.
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.