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Correct some grammar.
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2020-12-20 02:59:44 +00:00
svn path=/head/; revision=252421
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@ -70,18 +70,18 @@ hastd: <resource name> (<role>)
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.Pp
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If (and only if)
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.Nm
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operates in primary role for the given resource, corresponding
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operates in primary role for the given resource, a corresponding
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.Pa /dev/hast/<name>
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disk-like device (GEOM provider) is created.
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File systems and applications can use this provider to send I/O
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requests to.
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Every write, delete and flush operation
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.Dv ( BIO_WRITE , BIO_DELETE , BIO_FLUSH )
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is send to local component and replicated to the remote (secondary) node if it
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is available.
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is sent to the local component and replicated on the remote (secondary) node
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if it is available.
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Read operations
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.Dv ( BIO_READ )
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are handled locally unless I/O error occurs or local version of the data
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are handled locally unless an I/O error occurs or the local version of the data
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is not up-to-date yet (synchronization is in progress).
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.Pp
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The
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@ -100,38 +100,38 @@ The connection between two
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.Nm
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daemons is always initiated from the one running as primary to the one
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running as secondary.
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When primary
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When the primary
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.Nm
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is unable to connect or connection fails, it will try to re-establish
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connection every few seconds.
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Once connection is established, primary
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is unable to connect or the connection fails, it will try to re-establish
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the connection every few seconds.
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Once the connection is established, the primary
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.Nm
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will synchronize every extent that was modified during connection outage
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to the secondary
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.Nm .
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.Pp
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It is possible that in case of connection outage between the nodes
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It is possible that in the case of a connection outage between the nodes the
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.Nm
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primary role for the given resource will be configured on both nodes.
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This in turn leads to incompatible data modifications.
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Such condition is called split-brain and cannot be automatically
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Such a condition is called a split-brain and cannot be automatically
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resolved by the
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.Nm
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daemon as this will lead most likely to data corruption or lost of
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daemon as this will lead most likely to data corruption or loss of
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important changes.
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Even though it cannot be fixed by
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.Nm
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itself, it will be detected and further connection between independently
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itself, it will be detected and a further connection between independently
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modified nodes will not be possible.
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Once this situation is manually resolved by an administrator, resource
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Once this situation is manually resolved by an administrator, the resource
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on one of the nodes can be initialized (erasing local data), which makes
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connection to the remote node possible again.
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Connection of freshly initialized component will trigger full resource
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a connection to the remote node possible again.
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Connection of the freshly initialized component will trigger full resource
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synchronization.
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.Pp
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The
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A
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.Nm
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daemon itself never picks his role up automatically.
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daemon never picks its role automatically.
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The role has to be configured with the
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.Xr hastctl 8
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control utility by additional software like
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@ -139,7 +139,7 @@ control utility by additional software like
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or
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.Nm heartbeat
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that can reliably manage role separation and switch secondary node to
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primary role in case of original primary failure.
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primary role in case of the primary's failure.
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.Pp
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The
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.Nm
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