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Correct some grammar.

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This commit is contained in:
Jens Schweikhardt 2013-06-30 17:59:40 +00:00
parent 03630b541e
commit 1862d13b8a
1 changed files with 18 additions and 18 deletions
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36
sbin/hastd/hastd.8
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@ -70,18 +70,18 @@ hastd: <resource name> (<role>)
.Pp .Pp
If (and only if) If (and only if)
.Nm .Nm
operates in primary role for the given resource, corresponding operates in primary role for the given resource, a corresponding
.Pa /dev/hast/<name> .Pa /dev/hast/<name>
disk-like device (GEOM provider) is created. disk-like device (GEOM provider) is created.
File systems and applications can use this provider to send I/O File systems and applications can use this provider to send I/O
requests to. requests to.
Every write, delete and flush operation Every write, delete and flush operation
.Dv ( BIO_WRITE , BIO_DELETE , BIO_FLUSH ) .Dv ( BIO_WRITE , BIO_DELETE , BIO_FLUSH )
is send to local component and replicated to the remote (secondary) node if it is sent to the local component and replicated on the remote (secondary) node
is available. if it is available.
Read operations Read operations
.Dv ( BIO_READ ) .Dv ( BIO_READ )
are handled locally unless I/O error occurs or local version of the data are handled locally unless an I/O error occurs or the local version of the data
is not up-to-date yet (synchronization is in progress). is not up-to-date yet (synchronization is in progress).
.Pp .Pp
The The
@ -100,38 +100,38 @@ The connection between two
.Nm .Nm
daemons is always initiated from the one running as primary to the one daemons is always initiated from the one running as primary to the one
running as secondary. running as secondary.
When primary When the primary
.Nm .Nm
is unable to connect or connection fails, it will try to re-establish is unable to connect or the connection fails, it will try to re-establish
connection every few seconds. the connection every few seconds.
Once connection is established, primary Once the connection is established, the primary
.Nm .Nm
will synchronize every extent that was modified during connection outage will synchronize every extent that was modified during connection outage
to the secondary to the secondary
.Nm . .Nm .
.Pp .Pp
It is possible that in case of connection outage between the nodes It is possible that in the case of a connection outage between the nodes the
.Nm .Nm
primary role for the given resource will be configured on both nodes. primary role for the given resource will be configured on both nodes.
This in turn leads to incompatible data modifications. This in turn leads to incompatible data modifications.
Such condition is called split-brain and cannot be automatically Such a condition is called a split-brain and cannot be automatically
resolved by the resolved by the
.Nm .Nm
daemon as this will lead most likely to data corruption or lost of daemon as this will lead most likely to data corruption or loss of
important changes. important changes.
Even though it cannot be fixed by Even though it cannot be fixed by
.Nm .Nm
itself, it will be detected and further connection between independently itself, it will be detected and a further connection between independently
modified nodes will not be possible. modified nodes will not be possible.
Once this situation is manually resolved by an administrator, resource Once this situation is manually resolved by an administrator, the resource
on one of the nodes can be initialized (erasing local data), which makes on one of the nodes can be initialized (erasing local data), which makes
connection to the remote node possible again. a connection to the remote node possible again.
Connection of freshly initialized component will trigger full resource Connection of the freshly initialized component will trigger full resource
synchronization. synchronization.
.Pp .Pp
The A
.Nm .Nm
daemon itself never picks his role up automatically. daemon never picks its role automatically.
The role has to be configured with the The role has to be configured with the
.Xr hastctl 8 .Xr hastctl 8
control utility by additional software like control utility by additional software like
@ -139,7 +139,7 @@ control utility by additional software like
or or
.Nm heartbeat .Nm heartbeat
that can reliably manage role separation and switch secondary node to that can reliably manage role separation and switch secondary node to
primary role in case of original primary failure. primary role in case of the primary's failure.
.Pp .Pp
The The
.Nm .Nm