mirror of
https://gitlab.com/libvirt/libvirt.git
synced 2024-12-23 21:34:54 +03:00
944932bd43
This is a semi-automated conversion. The first conversion is done using "pandoc -f html -t rst". The result is then editted manually to apply the desired heading markup, and fix a few things that pandoc gets wrong. Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
34 lines
1.4 KiB
ReStructuredText
34 lines
1.4 KiB
ReStructuredText
============================
|
|
Virtual machine lock manager
|
|
============================
|
|
|
|
Libvirt includes a framework for ensuring mutual exclusion between
|
|
virtual machines using host resources. Typically this is used to prevent
|
|
two VM processes from having concurrent write access to the same disk
|
|
image, as this would result in data corruption if the guest was not
|
|
using a cluster aware filesystem.
|
|
|
|
Lock manager plugins
|
|
====================
|
|
|
|
The lock manager framework has a pluggable architecture, to allow
|
|
different locking technologies to be used.
|
|
|
|
nop
|
|
This is a "no op" implementation which does absolutely nothing. This
|
|
can be used if mutual exclusion between virtual machines is not
|
|
required, or if it is being solved at another level in the management
|
|
stack.
|
|
`lockd <locking-lockd.html>`__
|
|
This is the current preferred implementation shipped with libvirt. It
|
|
uses the ``virtlockd`` daemon to manage locks using the POSIX fcntl()
|
|
advisory locking capability. As such it requires a shared filesystem
|
|
of some kind be accessible to all hosts which share the same image
|
|
storage.
|
|
`sanlock <locking-sanlock.html>`__
|
|
This is an alternative implementation preferred by the oVirt project.
|
|
It uses a disk paxos algorithm for maintaining continuously renewed
|
|
leases. In the default setup it requires some shared filesystem, but
|
|
it is possible to use it in a manual mode where the management
|
|
application creates leases in SAN storage volumes.
|