Wednesday Feb 04, 2009

Working together with the MySQL team

One year after Sun acquired MySQL we see the positive results of this acquisition. Things are going very well in terms of collaboration, the teams are getting closer together and share the experience and the knowledge. If you want to know how the teamwork is seen from the Sun Cluster engineers, Thorsten Frueauf and myself, you should read this.

It was interesting for us to see that this interview was well observed by MySQL customers and community members. Although the interviews were not technical, they lead to technical questions. You can get more information here.

So if you are keen to see what the MySQL community wants to know about Sun Cluster, read the blog entry about MySQL and Sun Cluster.

Detlef Ulherr

Solaris Cluster Engineering 

Wednesday Sep 24, 2008

Announcing Availability of SCX 09/08

We are pleased to announce the availability of the latest Solaris Cluster Express (SCX)!  You can download the software here.

There are some major milestones reached in this release: It incorporates the first contribution from a community member!   And coming from a student, it is doubly delightful!!  It also provides early access to some of the new and exciting features that are being developed by the team.

What is new?

\* This release is runs on SXCE build 97. The version of Sun Management Center and other shared components are upgraded to be compatible with the Solaris Express Community Edition (SXCE) version.

\* The fencing mechanisms have been enhanced with the introduction of optional  fencing.  This provides a mechanism for the administrator to change the fencing mechanism either at global or at an individual disk level.

\* This release also has a new feature called zone clusters.  This feature makes it possible to form a virtual cluster based on the zones of a cluster.  This is made possible by the introduction of a new brand of zone called "cluster".  Needless to say, most of the code is available under a CDDL license like the rest of the software.  This feature is sure to make you reconsider your views about Open HA Cluster and Solaris Cluster!  Please refer to the clzonecluster(1CL)  man page for more details. You can find a cheat sheet for configuring a zone cluster here.

\* Use of Loopback File Driver (lofi) device for global-devices name space is introduced with this release.  A dedicated partition for the exclusive use of global-devices name space (i.e /globaldevices) is no longer the requirement.

\* As usual, there are the mandatory bug fixes and you can find them from the change log.

This release is a major milestone in the Open Source journey. For the list of all the exciting projects that the community is working on, please visit Open HA Cluster community.  This release of Solaris Cluster Express (SCX) will not work on OpenSolaris binary distribution (OpenSolaris 05.08).  For  the planned move to OpenSolaris binary distribution, visit Project Colorado.

Munish Ahuja

Madhan Kumar B

Jonathan Mellors

Venugopal N.S

Monday Jul 14, 2008

LDoms guest domains supported as Solaris Cluster nodes

Folks, when late last year we announced support for Solaris Cluster in LDoms I/O domains on this blog entry , we also hinted about support for LDoms guest domains. It has taken a bit longer then we envisaged, but i am pleased to report that SC Marketing has just announced support for LDoms guest domains with Solaris Cluster!!

So, what exactly does "support" mean here? It means that you can create a LDoms guest domain running Solaris, and then treat that guest domain as a cluster node by installing SC software (specific version and patch information noted later in the blog) inside the guest domain and have the SC software work with the virtual devices in the guest domain. The technically inclined reader would, at this point, have several questions pop into his head... How exactly does SC work with virtual devices? What do i have to do to make SC recognize these devices? Are there any differences between how SC is configured in LDoms guest domains, vs non-virtualized environments? Read-on below for a high level summary of specifics:

  • For shared storage devices (i.e. those accessible from multiple cluster nodes), the virtual device must be backed by a full SCSI LUN. That means, no file backed virtual devices, no slices, no volumes. This limitation is required because SC needs advanced features in the storage devices to guarantee data integrity and those features are available only for virtual storage devices backed by full SCSI LUNs.

  • One may need to use storage which is unshared (ie is accessed from only one cluster node), for things such as OS image installation for the guest domain. For such usage, any type of virtual devices can be used, including those backed by files in the I/O domain. However, for such virtual devices, make sure to configure them to be synchronous. Check LDoms documentation and release notes on how to do that. Currently (as of July 2008) one needs to add "set vds:vd_file_write_flags = 0" to the /etc/system file in the I/O domain exporting the file. This is required because the Cluster stores some key configuration information on the root filesystem (in /etc/cluster) and it expects that the information written to this location is written synchronously to the disks. If the root filesystem of the guest domain is on a file in the I/O domain, it needs this setting to be synchronous.

  • Network based storage (NAS etc.) is fine when used from within the guest domain. Check cluster support matrix for specifics. LDoms guest domains don't change this support.

  • For cluster private interconnect, the LDoms virtual device "vnet" can be used just fine, however the virtual switch which it maps must have the option "mode=sc" specified for it. So essentially, for the command ldm subcommand add-vsw, you would add another argument "mode=sc" on the command line while creating the virtual switch which would be used for cluster private interconnect inside the guest domains. This option enables a fastpath in the I/O domain for the Cluster heartbeat packets so that those packets do not compete with application network packets in the I/O domain for resources. This greatly improves the reliability of the Cluster heartbeats, even under heavy load, leading to a very stable cluster membership for applications to work with. Note however, that good engineering practices should still be followed while sizing your server resources (both in the I/O domain as well as in the guest domains) for the application load expected on the system.

  • With this announcement all features of Solaris Cluster supported in non-virtualized environments are supported in LDoms guest domains, unless explicitly noted in the SC release notes. Some limitations come from LDoms themselves, such as lack of jumbo frame support over virtual networks or lack of link based failure detection with IPMP in guest domains. Check LDoms documentation and release notes for such limitations as support for such missing features are improving all the time.

  • For support of specific applications with LDoms guest domains and SC, check with your ISV. Support for applications in LDoms guest domains is improving all the time, so check often.

  • Software version requirements. LDoms_1.0.3 or higher, S10U5 and patches 137111-01, 137042-01, 138042-02, and 138056-01 or higher are required in BOTH the LDoms guest domains as well as in the I/O domains exporting virtual devices to the guest domains. Solaris Cluster SC32U1 (3.2 2/08) with patch 126106-15 or higher is required in the LDoms guest domains.

  • Licensing for SC in LDoms guest domains follows the same model as those for the I/O domains. You basically pay for the physical server, irrespective of how many guest domains and I/O domains are deployed in that physical server.
  • This covers the high level overview of how SC is to be deployed inside the LDoms guest domains. Check out the SC Release notes for additional details, and some sample configurations. The whole virtualization space is evolving very rapidly and new developments are happening ever so quickly. Keep this blog page bookmarked and visit it frequently to find out how Solaris Cluster is evolving along with this space.


    Ashutosh Tripathi
    Solaris Cluster Engineering

    Wednesday Jun 04, 2008

    Solaris Cluster Express 6/08 available for download

    Solaris Cluster Express 6/08 is now available for download! You can download the DVD image here

    What is new in this release?

    \* This release runs on OpenSolaris Nevada build 86. The version of the Sun Management Centre is now 3.1.

    \* The HA agent for Solaris Containers is now enhanced to include support for the Solaris 9 Branded Zones on SPARC platform. This is very useful for those customers who still need to run some applications on Solaris 9 while taking advantage of the new features of Solaris 10 and above.

    \* The HA agent for PostgreSQL Database is now ehanced to support WAL shipping. This feature greatly enhances the deployment of PostgreSQL database in Enterprise deployments.

    \* Support for Solaris Containers configured with exclusive IP is included in this release.

    \* The SCX Geographic Edition is enhanced to support Oracle Data Guard based replication.

    \* This release also contains the mandatory bug fixes and other minor enhancements not mentioned above.

    Stay tuned for more milestones along the open source journey!

    Munish Ahuja
    Madhan Kumar B.
    Jonathan Mellors
    Arun Kurse
    Venugopal N.S.

    Thursday May 29, 2008

    Two Million Lines of Code

    One year ago, we announced that we would open source the entire Solaris Cluster product suite. Today, we are delivering on that promise six months ahead of schedule by releasing over two million lines of source code for the Solaris Cluster framework!

    Read the official press release and listen to a podcast with Meenakshi Kaul-Basu, Director of Availability Products at Sun.

    This third, and final, source code release follows the initial open sourcing of the Solaris Cluster agents in June, 2007 and Solaris Cluster Geographic Edition in December, 2007. As with the previous releases, the source code is available under the Common Development and Distribution License (CDDL) under the auspices of the HA Clusters community group on

    The open source version of Solaris Cluster is called Open High Availability Cluster. Although some encumbered parts of Solaris Cluster have not been open sourced, with this release, you can now build a fully functional HA Cluster purely from source.

    In addition to the source code for the product itself, Open HA Cluster includes source for the Sun Cluster Automated Test Environment (SCATE), man pages, and globalization.

    Consider getting involved in the HA Clusters community group:

    Nick Solter, Open HA Cluster tech lead and HA Clusters community group facilitator


    Oracle Solaris Cluster Engineering Blog


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