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Feature List

  1. Membership
    • courtesy of the CI project
    • includes libcluster and the cluster command (part of Cluster Tools)
  2. Internode Communication
  3. Filesystem
    • CFS is transparently stacked over any ext3 mount, making it instantly and coherently shared across the cluster
    • CFS can be used for the root and other filesystems
    • there is mount enforcement across nodes in the cluster so an NFS mount on any node is automatically done on all nodes;
    • reopen of files, devices, ipc objects when processes move is supported
    • CFS supports file record locking and shared writable mapped files (along with all other standard POSIX capabilities
    • HA-CFS is configurable for the root or other filesystems
    • Lustre is supported;
    • openGFS was supported but is not currently
    • GFS will be supported in OpenSSI 2.x but is not currently supported
  4. Process Management
    • very complete, including:
      • clusterwide PIDs
      • process migration and distributed rexec(), rfork() and migrate() with reopen of files, sockets, pipes, devices, etc.
      • vprocs
      • clusterwide signalling, get/setpriority
      • capabilities
      • distributed process groups, session, controlling terminal
      • surrogate origin functionality
      • no single points of failure (cleanup code to deal with nodedowns)
      • Load leveling at exec() time and during process execution
      • clusterwide ptrace() and strace
      • clusterwide /proc/<pid>, ps, top, etc.
      • threaded processes migrate as a group
      • process groups can migrate as a group
  5. Devices
    • there is a clusterwide device model via the devfs code
    • each node mounts its devfs on /cluster/node#/dev and bind mounts it to /dev so all devices are visible and accessible from all nodes, but by default you see only local devices
    • a process on any node can open a device on any node
    • devices are reopened when processes move
    • processes retain a context, even if they move; the context determines which node's devices to access by default
    • single, clusterwide /dev/pts
  6. IPC
    • all IPC objects/mechanisms are clusterwide:
      • pipes
      • fifos
      • signalling
      • message queues
      • semaphore
      • shared memory
      • Unix-domain sockets
      • Internet-domain sockets
    • reopen of IPC objects is there for process movement
    • nodedown handling is there for all IPC objects
  7. Clusterwide TCP/IP
    • HA-LVS is integrated, with extensions
    • extension is that port redirection to servers in the cluster is automatic and doesn't have to be managed.
  8. Paging/Swapping
    • not clusterwide
    • each node is independent
  9. Kernel Data Replication Service
    • it is in there (cluster/ssi/clreg)
    • no subsystems are using it
    • not there
  11. Shared Storage
    • we have tested shared FCAL and use it for HA-CFS
  12. HA interconnect
    • Bonding is supported
  13. DLM
    • is integrated with CLMS and is HA
  14. Sysadmin
    • services architecture has been made clusterwide
    • ps, top, ipcs are clusterwide by default
    • localview command can limit view to local node
  15. Init, Booting and Run Levels
    • system runs with a single init which will failover/restart on another node if the node it is on dies
  16. Application Availability
    • application monitoring/restart provided by spawndaemon/keepalive
    • services started by RC on the initnode will automatically restart on a failure of the initnode
  17. Timesync
    • NTP for now
  18. Load Leveling
    • for connection load balancing, using HA-LVS
    • process load leveling is on by default
    • process load leveling can occur at exec() time or during execution
    • applications must be registered to load level
  19. Packaging/Install
    • Have source patch, binary RPMs and CVS source options;
    • Can also build Debian packages from CVS source;
    • First node is incremental to a standard Linux install
    • Other nodes install via netboot, PXEboot, DHCP and simple addnode command;
  20. Object Interfaces
    • standard interfaces for objects work as expected
    • no new interfaces for object location or movement except for processes (rexec(), migrate(), and /proc/pid/goto to move a process)

This page last updated on Wed Jan 12 01:15:26 2005 GMT
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