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Release 1.0 of XtreemFS

XtreemFS 1.0 is out. XtreemFS now supports read-only replication with failover, data center replica maps, parallel reads and writes, and a native Windows client, among other new features.

Download it at

Watch our demo of replication and failover on youtube!

We demonstrate the XtreemFS replication and failover with an unmodified MPlayer. We play a regular movie file stored on two XtreemFS OSDs.



XtreemOS at Libre Software Meeting (RMLL'09)

Rencontres Mondiales du Logiciel Libre 2009 in Nantes, France

In 2009, LSM took place between July 7th and July 11th in Nantes, France ! An event managed by the Linux-Nantes Association, with active support from Free, Libre and Open Source Software users’ associations from the whole country.

On July 8th 2009, Surbhi Chitre of INRIA, Rennes gave a talk at RMLL'09 Nantes on OpenVZ integration in XtreemOS. She explained the need of XtreemOS, its importance as a solution to make grids easy and also the features that XtreemOS offered along with why and how it was new.

She illustrated her design of OpenVZ integration in XtreemOS, the difficulties in doing so and why OpenVZ was chosen for integration in XtreemOS.

Surbhi's presentation slides are available here.

RMLL'09 website:



XtreemOS at Linux Symposium

The Linux Symposium was held at Montreal, Canada, from July 13th to July 17th.


John Mehnert-Spahn (UDUS) gave a technical presentation of 45 minutes on his work "Incremental Checkpointing for Grids" on July 15th. John explained the motivation behind incremental checkpoint and its implementation in Linux SSI as well as its integration in XtreemOS. There was much interest in the implementation of incremental checkpoint. 

Linux Symposium 2009 - John

On 17th July Surbhi Chitre (INRIA) held a BOFs session for XtreemOS. She explained why XtreemOS is attractive and how it is a complete solution for grids. She also explained her work of integrating OpenVZ in XtreemOS, why it was chosen and the challenges in doing so. In her talk, she also gave a brief introduction to XtreemFS features. This was followed by a presentation by Louis Rilling of Kerlabs of Kerrighed Clusters which is supported by XtreemOS.

Linux Symposium 2009 - Surbhi


XtreemOS summer school: extended registration deadline!

The deadline to register for the first XtreemOS summer school has been extended to August 5th, 2009.

The deadline for grant request is now over (July 26th) and all the available grants have already been awarded.

School participants are encouraged to give a presentation of their research work during the doctoral symposium (Sept. 10th): if you want your presentation to be considered by the PhD organization committee, please send us the title of your talk and a one-page abstract to by August 24th.

Reminder: There will be an award to the best presentation!



XtreemOS at LinuxTag 2009

June 24-27, 2009

LinuxTag is Europe's leading event for Linux and free software. The four-day event has been taking place annually on the Berlin Exhibition Grounds since 2007. A total of 10,780 visitors from around the world attended LinuxTag 2009 in Berlin.

We presented XtreemOS and XtreemFS with a community booth at LinuxTag 2009 in Berlin.


During the four days of the exhibition we had a chat with about 60 visitors. For us it was very interesting to see what kind of problem the people had in mind to solve with XtreemFS. This ranged from using XtreemFS to replace VPN+Samba to video recording, editing and replication for streaming. Of course, there was quite some interest in using XtreemFS as a kind of cloud storage.

More than 10,000 visitors make LinuxTag the largest industry event in Europe - Wider-ranging conference programme and greater international participation (135 exhibiting companies and projects and around 300 speakers).

LinuxTag website

The next LinuxTag will take place from 9 to 12 June 2010 in Berlin!


Third project review meeting in Rennes (France)

The third project review meeting was held last July 8-9 in Rennes, France.

A delegation of XtremOS members gave presentations to allow the EC project officer and a reviewers' panel assessing the progress made by the consortium over the past year (June 2008- May 2009). The main technical and scientific achievements are the soon-to-be-publicly released second release of the XtreemOS system -including a graphical tool that makes the system easier to configure and install- and advanced features (integrated in XtreemOS v2.0).

The first demos of XtreemOS 2.0 were also run: a core scenario of the whole XtreemOS system and individual demos of stand-alone components (XtreemOS mobile device flavour, grid checkpointing/fault tolerance, virtual nodes...).

Review Meeting

This project review meeting was followed by a meeting of the Scientific Advisory Committee on July 9-10, 2009.

The XtremOS SAC is composed of experts from academic and industrial entities, both internal and external to the consortium, is a scientific evaluation consultative body.
It aims at maintaining the consortium at the forefront of knowledge worldwide and tackling specific technical difficulties.


XtreemOS at ISC'09

International Supercomputing Conference

The International Supercomputing Conference (ISC) is Europe’s leading Conference and Exhibition on High Performance Computing, Networking and Storage. The 2009 event took place in Hamburg, Germany, last June 23-26, 2009.

XtreemOS had a booth at ISC'09 showing the current software prototype (version 2.0 rc1) including demonstrations of the XtreemOS grid checkpointing service.

ISC’09-2 ISC’09-1

 Furthermore, the Wissenheim application (a multi-user virtual world) was also presented running on top of the XtreemOS Object Sharing Service (OSS) in charge of distribution and consistency management of the scene graph.

ISC'09 had 36 sponsors, 120 exhibitors and 1,670 attendees.

ISC'09 video blog:

ISC'10 will be held from May 31 – June 3, 2010, in Hamburg again!


XtreemOS position at STFC

Filed Under:
  • Grid Research and Development Programmer (FBU274)

£33,118 to £36,798 per annum, dependent on skills and ability.
2 years Fixed Term

The STFC e-Science Centre ( focuses on the exploitation of computing technology throughout STFC's programmes, its science communities, and the UK science and engineering base. The e-Science Centre is a partner in the European projects XtreemOS (XtreemOS) which aims to prototype a Grid operating system, and also holds a grant under the PIPPS scheme ( which is exploring the integration of grid middleware into commercial environments. Further, the e-Science Centre has a programme to develop Grid based tools to support the scientific facilities at STFC, and also within the UK.

The e-Science Centre is seeking a highly motivated individual to undertake research and technology development, including software implementation, on these and other projects. The post will explore the interoperation of Grid middleware (XtreemOS, GLite and its use in commercial applications. You will have a good first degree and preferably a postgraduate qualification in Computer Science or related subject, or equivalent relevant experience. A proven ability in research and knowledge of the technologies of these projects are desirable, including: GRID middleware; Web Services; IT security; software design and implementation (e.g. C and Java). The post will require regular travel to partners in Europe, the promotion of the work of the projects via academic publications, and the development of further R&D opportunities, so good team working and communication skills are essential. Training will be available as appropriate, in accordance with STFC's commitment to the Investors in People scheme.

An excellent index linked pension scheme and generous leave allowance are also offered.

For further information and how to apply: please visit, telephone 01235 446677 or e-mail quoting reference number FBU274.

Closing date for applications is 17th July 2009.
Interviews will be held on 7th August 2009.


XtreemOS summit at Euro-Par 2009: early registration on June 30


The XtreemOS summit will include talks about XtreemOS services and components. Selected demonstrations will show the benefits of using XtreemOS technology followed by a slot  for open discussion. There will be no call for papers.

Tentative Program & speakers

The topics covered in the XtreemOS Summit include:

  • Main objectives of XtreemOS (talk) - Thilo Kielmann, Vrije universiteit Amsterdam, the Netherlands
  • Security model (talk) - Alvaro Arenas, Science and Technology Facilities Council, the United Kingdom
  • Resource matching and scheduling (talk) - Guillaume Pierre, Vrije Universiteit Amsterdam, the Netherlands
  • Replica management and parallel I/I in XtreemFS (talk) - Björn Kolbeck, Zuse Institue Berlin, Germany
  • Applications and demonstrations (demo) - coordinated by Bernd Scheuermann, SAP, Germany
  • Open Q&A (discussion)

Registration, a two-step process

  1. Register at the EuroPar 2009 conference - early registration is June 30
  2. Inform the XtreemOS organizers on your participation sending  an email  to


Get acquainted with one XtreemOS partner: Consiglio Nazionale delle Ricerche (CNR)

Consiglio Nazionale delle Ricerche (CNR)

The Italian National Research Council (CNR) is a public organization whose purpose is to carry out, promote, and improve research activities in the main sectors of knowledge, spread their results and help their transfer to the industry and their application, to further the scientific, technological, economic and social development of Italy. To this purpose, a network of CNR institutes is distributed all over Italy. To promote international cooperation and contribute to the development of key technologies, CNR participates in agreements, contracts and research projects with the European Union and with the other international organizations; among them  the CNR membership of ERCIM and of W3C. Two of the CNR institutes, ISTI and ICAR,  are involved in the development of XtreemOS.

CNR's contributions to XtreemOS

  • Scalable, Highly available services

Within XtreemOS, the CNR team is involved in the development of the highly available  services that tie up into a system the XtreemOS individual machines on a grid. CNR has developed the Service/Resource Discovery System (SRDS), that leverages on overlay networks and exploits the functionalities of the XtreemFS-F basic layer of XtreemOS,

The SRDS daemons run distributed over the nodes of the XtreemOS platform, and offer resource and service discovery services to other XtreemOS modules and applications. SRDS resolves key-based and range-based queries, over both dynamic and static information. The main  clients of the SRDS are currently the Application Execution Management (AEM) and the Job Directory Service (JDS) modules. They access information about computing resources and running jobs within a Virtual Organization.

The SRDS layered architecture employs a combination of overlay networks and query resolution algorithms to improve on previous protocols (like LDAP) in terms of scalability,  fault tolerance and flexibility. We exploit overlays based on the Distributed Hash Tree (DHT) paradigm, as well as custom networks like the RSS (also developed within XtreemOS, by VUA). The SRDS provides scalability, reliability and high availability on very large Grids, while also being able to satisfy the needs of diverse clients in terms of information management primitives and of access protocols (DIXI, RMI, Https).

CNR’s contributions

  • XtreemFS

The CNR team also participates in the development of the Object Storage Device component (OSD) of XtreemFS, the XtreemOS File System. According to the object-based storage design paradigm for parallel and distributed file systems, within XtreemFS the content of a single file is represented by one or more objects. The OSD is responsible for storing file content as a set of objects, providing access to file data interacting with the other XtreemFS components.

CNR contributes to the second development phase of XtreemFS focusing on testing it for POSIX-compliance. In this phase, the NTFS-3G test suite has been selected and is being used to assess the XtreemFS behaviour.

Istituto di Scienza e Tecnologie dell'Informazione “A. Faedo

 ISTI logoThe Institute of Information Science and Technologies (ISTI) is located in the CNR Research Area of Pisa. ISTI was constituted in September 2000, becoming fully operational in 2002, as a result of a merger between the former CNUCE and the IEI institutes of CNR. As a result, ISTI is the largest public IT research institute in Italy, enrolling about 90 permanent researchers, for a total of about 170 personell units with research fellows and PhD students.

The domain of competence of ISTI covers Information Science, related technologies and a wide range of their applications. ISTI groups into 5 main thematic areas its 16 research laboratories, covering IT application fields as different as Visual Computing from Knowledge discovery, and of course including High Performance Computing (

Basic and applied research in the IT domain requires close integration of all components of the research community and academia with wide sectors of the industry, of business and of society at large. ISTI hosts the Italian Regional W3C Office, and is actively involved in collaborations with the academic world and in cooperative research, as well as in training and development programs, both national and international.

Istituto di Calcolo e Reti ad Alte Prestazioni del Consiglio Nazionale delle Ricerche (ICAR-CNR)

 ICAR logoThe Institute of High Performance Computing and Networking (ICAR) ( has been established on May 2001 and is operative since June 2002. The Institute is located at Rende, Cosenza (Italy) and has two branches in Naples and in Palermo. ICAR currently enrolls about 60 researchers and technicians, distributed on the three sites. ICAR performs basic and applied research in the areas of High Performance Computing and Networking and Intelligent Systems, by cooperating with the academic world and other private and public research organizations active in these areas. In addition to its research activities, the Institute works on pre-competitive development and technological transfer of research results, and carries out educational and training activities, through scholarships and research fellowships, advanced post-graduate specialization courses, and non-university higher education activities.



XtreemOS keynote talk at BNCOD 2009

Filed Under:

Domenico Laforenza (CNR) will give a keynote talk about XtreemOS at the 26th British National Conference on Databases (BNCOD 2009) to be held at Birmingham University from the 7th to 9th of July 2009.

The theme of BNCOD 2009 will be "Dataspace: the Final Frontier". Dataspace is a term recently coined to denote the expansion of the database topic into the broader area of managing large numbers of diverse but interrelated data sources of many varying forms.

D.Laforenza's talk is entitled "XtreemOS: Towards a Grid-enabled Linux-based Operating System" and present XtreemOS, as a first European step towards the creation of a true open source operating system for Grid platforms. 


Get acquainted with one XtreemOS partner: Red Flag Software

Filed Under:

RedFlagSince its founding on June 2000, Red Flag Software is growing rapidly and firmly to be the largest Linux company in Asia with more than 180 employees. Under headquarter located in Beijing, there are two subsidiaries in Guangzhou and Shanghai, and well-established sales channels and service networks are deployed nationwide. The product line includes high-end Linux server OS, cluster system, desktop OS, embedded system, technical support services and trainings.

Our XtreemOS team is responsible for integrating XtreemOS system into Asianux opration system, including packaging, testing and integration, to promote its usage in China and even Asia.Our work also includes making some technical documents of XtreemOS Chinese.

Now there are four people in the team who are fully or partly devoted to the relevant work of XtreemOS project.


Red Flag Linux Know more about Redflag, please refer to:


Asianux Know more about Asianux, please refer to:


XtreemOS at ISC'09: come and visit us!


XtreemOS has a booth at the International Super Computing Conference in
Hamburg, Germany.

The brand new 2nd software release and selected demo
applications will be presented from June 24th to June 25th, 2009 at our
booth #734.

The floorplan is available here.

Conference website:


XtreemOS paper at COMPSAC 2009 Doctoral Symposium

Efficient Management of Consistent Backups in a Distributed File System


Authors: Jan Stender


Abstract: Setting up backup infrastructures for large-scale data management systems that can be operated cheaply and accessed with low latency has emerged as a practical problem. As a solution, we present a highly scalable and cost-efficient architecture for backup management in a distributed file system. We describe techniques for the creation of consistent backups at runtime, as well as approaches to resource management in connection with an integrated backup architecture.

COMPSAC 2009: website


Seattle, Washington, July 20-24, 2009

The Doctoral Symposium at COMPSAC will provide an international forum for doctoral students to interact with other students and faculty mentors. Since 2006, COMPSAC has been designated as the IEEE Computer Society Signature Conference on Software Technology and Applications.

The Doctoral Symposium seeks to bring together PhD Students working in computer software and applications and related fields. Selected students will have the opportunity to present and discuss their research goals, methodology, and preliminary results within a constructive and international atmosphere.

The Symposium organizers will strive to provide useful guidance for completion of the dissertation research and motivation for a research career. The Symposium is intended for students who have already settled on a specific research proposal and have produced limited preliminary results, but have enough time remaining before their final defense to benefit from the fruitful Symposium discussions. Due to the mentoring aspect of the event, the Symposium will be open only to the students and mentors participating directly in the event.

In coordination with the technical theme of COMPSAC 2009, topics pertaining to software engineering of critical infrastructure systems such as civil, telecommunications, and medical systems will be of particular interest. Related topics include, but are not limited to, requirements analysis, co-analysis and co-design, modeling, design, development, testing, measurement, verification and validation for performance, safety, security, and dependability constraints of such systems. As effective construction of critical infrastructure systems is not limited solely to the field of computer science and engineering and is truly a multidisciplinary effort, submissions addressing multidisciplinary research topics are particularly encouraged.


Get acquainted with one XtreemOS partner: XLAB

Filed Under:

XLAB is a medium-sized company whose major source of income is the family of ISL Online
business communication solutions. Other products include medical imaigng software and the Gaea+ GIS/virtual globe solution.

XLAB logo

Having been awarded multiple innovation prizes, XLAB strives to integrate latest advances in the
fields of communication security, scalability, fault tolerance, and large dataset processing into the afore-mentioned products, thus fitting naturally with the XtreemOS project.

XLAB in XtreemOS

XLAB's most prominent role in the project is in the application execution management, where we
provided an initial prototype of the resource selection using various resource filters. We proceeded by supporting the job scheduler with a reservation management system. The job scheduler can thus rely on the timetables kept by each worker node, and a coordinating service on the level of the administration domain. As a future challenge, we will be tackling the reservation of resources between multiple domains.

In parallel to this work, we provided the implementation to the Linux SSI scheduler, which performs the load balancing of the system. It relies on an interchangeable set of modules for system metrics and scheduling policies. Hence, it can take advantage of either the ready-made probes into the kernel, or use custom ones developed by third party or the users themselves.
To support the whole system of the services in the XtreemOS, we developed a staging framework
that supports services written in Java and client programs in Java or C. It enables a distribution of
the services and asynchronous invocation using Java constructs, without having to deal with the
actual connectivity issues.

Related closely to the above is our work on security services. We developed a service to maintain
the Virtual Organisation policies, providing a way to isolate the users' jobs to only those resources that belong to the required VO, which happens already in the process of the resource selection.

Our project activities also include the development of an automatic scheduling manager for the
LinuxSSI flavour. We contributed to the definition of requirements in the early stages and have
continued to assess their fulfillment.

In the last year of the project we will lead the preparation of demonstrations and will also be involved in training activities, as a recent post about Kiberpipa presentation shows.



Two XtreemOS papers accepted at Euro-Par 2009

 Euro-Par 2009 logo


"The Architecture of the XtreemOS Grid Checkpointing Service"


Authors: John Mehnert-Spahn, Thomas Ropars, Michael Schoettner, Christine Morin

Abstract - The EU-funded XtreemOS pro ject implements a grid operating system (OS) transparently exploiting distributed resources through the SAGA and POSIX interfaces. XtreemOS uses an integrated grid checkpointing service (XtreemGCP) for implementing migration and fault tolerance. Checkpointing and restarting applications in a grid requires saving and restoring applications in distributed heterogeneous environments. In this paper we present the architecture of the XtreemGCP service integrating existing system-specific checkpointer solutions. We propose to bridge the gap between grid semantics and system-specific
checkpointers by introducing a common kernel checkpointer API that allows using different checkpointers in a uniform way. Our architecture is open to support different checkpointing strategies that can be adapted according to evolving failure situations or changing application requirements. We also present how to avoid resource conflicts during restart. Finally, we discuss measurements numbers showing that the XtreemGGP architecture introduces only minimal overhead.


"Active Optimistic Message Logging for Reliable Execution of MPI Applications"


Authors: Thomas Ropars, Christine Morin

Abstract -To execute MPI applications reliably, fault tolerance mechanisms are needed. Message logging is a well-known solution to provide fault tolerance for MPI applications. It has been proved that it can tolerate a higher failure rate than coordinated checkpointing. However pessimistic and causal message logging can induce high overhead on failure free execution. In this paper, we present O2P, a new optimistic message logging protocol, based on active optimistic message logging. Contrary to existing optimistic message logging protocols that save dependency information on reliable storage periodically, O2P logs dependency information as soon as possible to reduce the amount of data piggybacked on application messages. Thus, it reduces the overhead of the protocol on failure free execution, makes it more scalable and simplifies recovery. O2P is implemented as a module of the Open MPI library. Experiments show that active message logging can effectively improves scalability and performance of optimistic message logging.


Euro-Par conference website:


Presentation of XtreemOS in Kiberpipa, Ljubljana, Slovenia

On April 14th XLAB made an XtreemOS training session in the Kiberpipa slot. Marjan Sterk and Matej Artač presented the XtreemOS project and its goals, and demonstrated its usage from the perspective of a VO administrator, a resource administrator, and a VO user.

The audience consisted of Linux users, who showed interest in the project's results.

Kiberpipa - Xlab

The video of the presentation (in Slovenian) is available here.

(Source: wikipedia) -  Kiberpipa ('Cyberpipe') is a hackerspace in Ljubljana, Slovenia, established in 2001 as a part of the K6/4 Institute.

The hackerspace operates as a cultural centre, computer laboratory and Internet café (with free wireless access). Kiberpipa engages primarily in open source programming and the recycling of computer devices.
It organises workshops, lectures, and entertainment and information events.



XtreemOS at EuroSys2009

At the Eurosys2009 conference, Kim-Thomas Moeller from Universitaet Duesseldorf presented XtreemOS's object sharing service in a work-in-progress talk and during the poster session (pdf). The object sharing service addresses the problem of managing shared states in distributed and parallel applications. It aims at simplifying the development of grid applications by abstracting from access location, replica management, data consistency, and fault tolerance.

 Eurosys09  poster session - Courtesy of Wanja Hofer

EuroSys2009 poster session - Courtesy of Wanja Hofer

XtreemOS was also represented by Guillaume Pierre from Vrije Universiteit Amsterdam who presented the "Highly Available and Scalable Grid Services" (pdf) at WDDDM and Christine Morin from INRIA who gave an invited talk at HPCVirt ("Virtualization in XtreemOS Distributed Operating System: Requirements and Opportunities").

Eurosys2010 will be located in Paris, with XtreemOS's project leader Christine Morin as the conference's general chair.

Christine Morin and Gilles Muller, respectively general chair and PC chair for EuroSys2010

Christine Morin and Gilles Muller will be EuroSys2010 general chair and PC chair respectively

- Courtesy of Wanja Hofer


XtreemOS-MD first release available!

The Mobile Device Flavor of XtreemOS (aka. XtreemOS-MD) has been recently released and it is available for downloading and testing from Mandriva repositories under the directory devel/xtreemos/2008.0/mobile.

The XtreemOS-MD software distribution is our first released implementation XtreemOS project for Mobile Devices, which integrates the Grid client functionality in Mobile Devices. The most important features are:

  • Grid available out of the box: the installation is as simple as a single click on a Web page and no user configuration is required, only your username and password for the Grid.
  • Grid login uses a plug-able, Single-Sign-On system. Login may be manual or automatic.
  • Automounting of the home Grid filesystem volume when user logs-in the Grid.
  • User may launch processes in the Grid.
  • User may run applications compliant with SAGA API (further work is needed for complete support)

XtreemOS-MD is currently available for two platforms:

  • Nokia N800 and Nokia 810 Internet Tablets running Maemo 2008 distribution.
  • Angstrom 2007.12 (currently, the last stable version until the date of publication of XtreemOS-MD, 2008/02/28) running in a Qemu emulator.

Installation is easier in Maemo 2008 (i.e. Nokia N8x0), because the platform provides the
functionality of "click to install" without needing to login as root in your mobile device. In Angstrom, installation requires to download and execute an installation script as root on top of a QEMU emulator.


General Technical Meeting in Amsterdam

Filed Under:

From March 23rd to 27th, we held our sixth general meeting in Amsterdam, the Netherlands. We had about 50 XtreemOS members (senior researchers, PhD students, engineers, students...) in attendance at Vrije Universiteit, our Dutch host.

GTM - Amsterdam (2)

GTM - Amsterdam

The "rallying cry" of this general meeting was the preparation of the second software release of the XtreemOS system, closing ranks around the next release candidate and working together towards an improved system with advanced features and an easier installation and configuration process.
This week gathering was divided into several slots dedicated to internal workpackage meetings, cross-workpackage meetings and joint sessions on common research topics and shared interests (checkpointing, virtualization, cloud computing...), tutorial (security services, packaging...) and of course plenary sessions (software roadmap, demonstration activities...) when XtreemOS brains were intensively "boiling" ;-)

XtreemOS also took the opportunity of this Dutch week to meet a delegation of representatives from the S-Cube and Reservoir projects: this aimed at making mutual general presentations of the three projects, investigate potential areas of collaboration and identify contact persons to coordinate collaboration activities.

No need to say that this general technical meeting was, once again, intense and frantic but definitely productive and exciting too!

A friendly social event allowed all our hard workers to relax first during a tour boat on the canal of Amsterdam then in an Indonesian restaurant...ideal to pep every one up! :-)

GTM Amsterdam (3)