vxrlink(1M) VxVM 3.5 vxrlink(1M)
1 Jun 2002
NAME [Toc] [Back]
vxrlink - perform VERITAS Volume Manager operations on RLINKs
SYNOPSIS [Toc] [Back]
vxrlink [-g diskgroup] [-r rvg] assoc rvg rlink
vxrlink [-a | -c checkpoint | -f] [-g diskgroup] [-r rvg] att rlink1
[rlink2...]
vxrlink [-g diskgroup] [-r rvg] cplist rlink
vxrlink [-g diskgroup] [-r rvg] det rlink
vxrlink [-g diskgroup] [-r rvg] dis rlink
vxrlink [-c checkpoint | -w] [-g diskgroup] [-r rvg] pause rlink
vxrlink [-g diskgroup] [-r rvg] recover rlink
vxrlink [-c checkpoint] [-g diskgroup] [-r rvg] restore rlink
vxrlink [-g diskgroup] [-r rvg] resume rlink
vxrlink [-g diskgroup] [-i interval [-t timestamp_freq]] [-r rvg] stats
rlink
vxrlink [-g diskgroup] [-i interval [-t timestamp_freq]] [-r rvg]
status rlink
vxrlink [-g diskgroup] [-r rvg] updates rlink
vxrlink [-g diskgroup] [-r rvg] verify rlink | rvg
DESCRIPTION [Toc] [Back]
The vxrlink utility performs VERITAS Volume Manager (VxVM) operations
on RLINKs (rlinks). vxrlink is specific to VERITAS Volume Replicator
(VVR), which requires a valid license. The first operand is a keyword
that determines the specific operation to perform.
Each operation can be applied to only one disk group at a time. Any
rlink and rvg operands are used to determine a default local disk
group, according to the standard disk group selection rules described
in vxintro(1M). When an rvg is not specified, the RVG currently
associated with the specified RLINK is used. A specific local disk
group can be selected with -g diskgroup.
KEYWORDS [Toc] [Back]
assoc Associates an rlink with an rvg. Both the rlink record and
the rvg record are modified. Alternatively the association
could be specified during the vxmake of the RVG. Secondary
RVGs (that is, an RVG that does not have the primary
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attribute set) have at most one rlink associated with them.
Where as a primary RVG has one rlink for each secondary RVG
associated with it with a maximum of 32.
att Attaches an rlink to an rvg. The rlink must already be
associated with the rvg before the attach operation.
When a primary rlink is successfully attached, VVR sets up a
connection between the primary and secondary hosts and
replicates the writes received by the primary data volumes
to the corresponding secondary data volumes. Before
attaching a primary rlink ensure that the secondary RLINKs
are attached, the secondary Storage Replicator Log(SRL) is
associated with the secondary RVG, and all of the secondary
data volumes are associated with the secondary RVG. For the
attach to succeed on the primary, the remote_host,
remote_dg, and remote_rlink attributes must be set on both
the primary and the secondary RLINKs. The attributes can be
set, while creating the RLINKs, using the vxmake or vxedit
set command. The attach fails if the primary RVG does not
have an SRL associated with it. The exception to this rule
is when the primary RVG is in passthru error mode and does
not need an SRL associated with it. In this case, the
application writes are passed directly to the data volumes
and replication is not taking place.
An attach on the primary requires that one of the options
-a, -c checkpoint, or -f is specified.
An attach of a secondary RLINK does not require any options
because the attach only indicate the readiness of the RLINK
to be used for replication.
cplist Displays information about all existing checkpoints
associated with the given rlink, including their name, size,
and percentage of SRL used. If SRL usage reaches 100%, the
checkpoint overflows and becomes unusable, as indicated by
the output message "<Checkpoint overflowed>." Note that
only secondary checkpoints (created using vxrlink -c
checkpoint pause on the secondary) are associated with an
rlink. Primary checkpoints (created using vxrvg -c
checkpoint checkstart on the primary) are associated with
the RVG, and can be listed using vxrvg cplist.
det Detaches an rlink from an rvg. This makes the RLINK STALE.
Note: A STALE RLINK requires a full resynchronization of its
data volumes before replication can be resumed.
dis Dissociates an rlink from the rvg with which it is
associated. This can not be executed if the RLINK is
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currently attached.
pause Pauses updates to the rlink until vxrlink resume is
executed. New updates are logged while the RLINK is paused,
and are applied once the RLINK is resumed.
On the primary, if the Data Change Maps(DCMs) are being
replayed on the RLINK to be paused, the replay pauses until
the RLINK is resumed. If more than one RLINK is involved in
the replay, the replay pauses for all RLINKs involved.
Resuming the paused RLINK allows the replay to resume for
all RLINKs. Detaching the paused RLINK allows the replay to
resume for the remaining attached RLINKs.
On the secondary a -c checkpoint option is valid and can be
used to mark a point at which a backup of the secondary has
been taken.
Note: The -w option is used only on the secondary side and
only in special cases to force the secondary RLINK into the
FAIL state. This might have to be done before restoring the
secondary from an online backup.
recover Recovers rlink after rebooting machine.
restore Restores the rlink from FAIL state to ACTIVE. Valid only
for secondary RLINKs. Used when restoring data volumes at a
secondary site from online backup data maintained at the
secondary site (as opposed to restoring secondary data
volumes using data copied from the primary site).
Note: This keyword must be used with the -c option to
specify the checkpoint corresponding to the backup that is
used to perform the restore.
resume Resumes updates to an rlink in the PAUSE state. After
updates are resumed, all updates that were logged while the
RLINK was paused are written to the secondary.
stats Displays network statistics for the given rlink. The
displayed values are cumulative, except when used with the
-i interval option. When used with -i interval option, the
first line of statistics provide cumulative values and
subsequent lines show the change during the last interval
seconds.
The following values are displayed under the heading
Messages:
# Number of messages transmitted.
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Blocks Number of 1024-byte blocks transmitted.
RT Average round-trip time per message.
The following values are displayed under the heading Errors:
Timeout Number of timeouts errors. A timeout error occurs
when an acknowledgement for a message is not
received from the remote host within the timeout
period.
Stream Number of stream errors. Stream errors occur when
the RLINK attempts to send messages faster than
the network can handle.
Memory Number of errors because of insufficient buffer
space on the Secondary.
The heading Flow Control displays values that indicate how
fast the RLINK is trying to send messages. If VVR is using
the UDP transport protocol, the values Delays, NW Bytes and
NW Delay are displayed. If VVR is using the TCP transport
protocol, only the Delays value is displayed.
Delays Cumulative time the RLINK had to wait while it was
flow controlled. The value is displayed in onehundredth
of a second.
NW Bytes Number of bytes that can be transmitted without
flow controlling and introducing any intervening
wait. If an RLINK does not experience network
errors, VVR steadily increases the NW Bytes to
permit more data to be transmitted. If an RLINK
experiences network error, VVR tries to flow
control by reducing this number. The minumum value
is 5000 bytes.
NW Delay The amount of wait introduced after transmission
of NW Bytes of a message. If NW Bytes is at 5000
bytes and the RLINK continues to experience
errors, VVR increases NW Delay. The value is
displayed in one-hundredth of a second. The
maximum value is 100 (1 second). A steady high
value of NW Delay usually indicates a network
problem.
If VVR is using the UDP transport protocol, the current
value of Timeout is displayed:
Timeout Message timeout value in milli-seconds. The value
is computed dynamically. If an acknowledgement for
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a message is not received from the remote host
within this time period, the message is considered
lost and is retransmitted.
status Only valid on the primary, status displays the state of the
secondary image represented by the given rlink. If the rlink
is not up-to-date, it shows the number of updates and blocks
the image is behind, and the percentage of the SRL being
used by this rlink. The -i interval option allows the
status command to be executed at the given interval.
updates Only valid on the secondary, updates displays the update ID
of the latest update received by the secondary, as well as
number of updates primary is ahead of secondary. This
information can be used to determine the most up-to-date
secondary RVG. The update information is invalid if the
secondary has not received any updates from the primary.
The update information is unavailable if the secondary has
been rebooted after the primary has gone down.
verify Displays configuration information for the rlink.
Configuration update messages are sent to each secondary
RLINK when appropriate. Any configuration errors detected at
a secondary are logged. This command displays the
configuration status of the given RLINK. If an rvg is
specified instead of an RLINK, configuration status
information is displayed for each RLINK associated with the
RVG. If an RVG is specified with the -r option, it is used
only to help determine a default local disk group, according
to the standard disk group selection rules described in
vxintro(1M).
OPTIONS [Toc] [Back]
-a Use with the att command on the primary to attach a group of
RLINKs for automatic synchronization(autosync). The
autosync operation fails if all the data volumes do not have
associated DCMs or if any of the RLINKs are unable to
connect to the respective secondary hosts. The -a option
cannot be used on the secondary or with the -f or -c option.
-c checkpoint
Use with the att command on the primary to attach an rlink
which is consistent up to the point indicated by the
checkpoint string. The checkpoint indicates, to VVR, the
writes that must be replayed from the primary host to the
seconday hosts, to bring the secondary hosts up to date.
The -c option is also required with the restore command to
specify the checkpoint to be used for restore.
-f Use with the att command on the primary to force an attach
of an rlink when the secondary data volumes are completely
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synchronized with the primary data volumes.
Use the -f option with care because it may result in loss of
data if used incorrectly. Use the -f option to attach the
rlink only if you are sure that the rlink is up to date.
-g diskgroup
Specifies the local diskgroup for the operation. The
diskgroup can be specified either by name or by disk group
ID. See vxdg(1M) for more information on disk groups.
-i interval
Executes the stats or status command every interval seconds.
-r rvg Specifies the name of the RVG with which the rlink is
associated. If not supplied, the RLINK record is examined to
retrieve the name of the associated RVG.
-t timestamp_freq
Specifies how frequently timestamps are to be output, in
terms of the number of lines. For example, -t 1 prints a
timestamp on each line, and -t 5 prints a timestamp on every
fifth line. This option is only valid for the stats and
status commands when the -i option is also specified.
-w Forces a secondary rlink into the FAIL state. Used only in
special circumstances (secondary online backup). The rlink
is marked inconsistent.
EXIT CODES [Toc] [Back]
The vxrlink utility exits with a non-zero status if the attempted
operation fails. A non-zero exit code is not a complete indicator of
the problems encountered, but rather denotes the first condition that
prevented further execution of the utility.
See vxintro(1M) for a list of standard exit codes.
SEE ALSO [Toc] [Back]
vxdg(1M), vxedit(1M), vxintro(1M), vxmake(1M), vxplex(1M),
vxprint(1M), vxrvg(1M), vxvol(1M), vradmin(1M)
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