---
** [tickets:#1859] fm: Split-brain avoidance in OpenSAF using fencing**
**Status:** assigned
**Milestone:** 4.7.2
**Created:** Wed Jun 01, 2016 01:49 PM UTC by Hans Nordebäck
**Last Updated:** Wed Jun 01, 2016 01:49 PM UTC
**Owner:** Hans Nordebäck
Split brain can occur in OpenSAF if either both links between the two
controllers are "lost"
or one of the controller "live hangs".
OpenSAF handles and detects split-brain via FM and uses PLM to fence the
offending system controller using reboot. PLM only supports target environments
running on particular hardware
Only a few split-brain cases has been seen and only when running in virtualized
environments:
1) Virtual switches problems that makes SCs isolated from each other.
2) Both TIPC links between the SCs are "down/lost", e.g. TIPC tolerance time
too low, non-redundant links, etc.
3) A system controller in a virtual machine is "live hanging" for several
seconds, e.g. due to
live migration/snapshotting.
To be able to do power fencing in a virtualized environment this ticket suggests
to use STONITH.
When FM detects its peer is not available, both active and standby, in an
virtualized environment the active FM system controller will use STONITH to
power fence the FM standby system controller, (not power reset). The FM standby
system controller will also power fence, but with a delay, the active FM
system controller.
This will solve the above identified split-brain cases.
---
Sent from sourceforge.net because opensaf-tickets@lists.sourceforge.net is
subscribed to https://sourceforge.net/p/opensaf/tickets/
To unsubscribe from further messages, a project admin can change settings at
https://sourceforge.net/p/opensaf/admin/tickets/options. Or, if this is a
mailing list, you can unsubscribe from the mailing list.
------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
_______________________________________________
Opensaf-tickets mailing list
Opensaf-tickets@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/opensaf-tickets
