vxrlink(1M) vxrlink(1M)
NAME
vxrlink - perform Veritas Volume Manager operations on RLINKs
SYNOPSIS
vxrlink [-g diskgroup] [-r rvg] assoc rvg rlink
vxrlink [-a | -b | -c checkpoint | -f] [-g diskgroup] [-r rvg]
att rlink1 [rlink2...]
vxrlink [-g diskgroup] [-r rvg] -c checkpoint checkdelete rlink
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 [-g diskgroup] [-r rvg] -c checkpoint
restore rlink
vxrlink [-g diskgroup] [-r rvg] resume rlink
vxrlink [-g diskgroup] [-e] [-i interval [-t timestamp_freq]]
[-r rvg] stats rlink
vxrlink [-g diskgroup] [-i interval [-t timestamp_freq]]
[-r rvg] [-T] status rlink
vxrlink [-g diskgroup] [-r rvg] [-T] updates rlink
vxrlink [-g diskgroup] [-r rvg] verify rlink | rvg
DESCRIPTION
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 asso-
ciated with the specified RLINK is used. A specific local disk group can be selected with -g diskgroup.
KEYWORDS
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 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 maxi-
mum 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, -b 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.
checkdelete
Deletes the specified Secondary checkpoint.
Note: This command must be run only on the Primary.
By default, VVR allows the creation of a maximum of 46 checkpoints. When the number of checkpoints exceeds this number, VVR
prompts you to select which of the checkpoints should be deleted.
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.
Note: The cplist command must be run only on the Primary.
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 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.
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 han-
dle.
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 one-hundredth of a sec-
ond.
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 max-
imum 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 a message is not
received from the remote host within this time period, the message is considered lost and is retransmitted.
When used with the -e option, the stats command displays extended network statistics. The displayed values are cumulative unless
an interval is specified using the -i option. In this case, cumulative values are only shown on the first line of statistics,
and subsequent lines show the change during the previous interval.
The output of the command with the -e option is specified is displayed under two headings: Messages and Errors. The Messages
heading displays the following information:
Number of blocks sent
The number of 512-byte blocks that have been transmitted. (If the -e option is not specified, the displayed Blocks
value only indicates the number of blocks that have been acknowledged.)
The Errors heading has nine fields that indicate the nature of the error that has been encountered. Three of these headings are
similar to those shown by the command if the -e option is not specified. The following errors may be shown:
No memory available
There is not enough system kernel memory to process the message.
No message slots available
There is not enough memory to store the packets of a message that have arrived out of sequence. (If a packet arrives
out of sequence, it must be stored in a message buffer until all the related out-of-sequence packets arrive, and can be
assembled.)
No memory available in nmcom pool on Secondary
The buffer space (whose size is determined by the value of VVR tunable vol_max_nmpool_sz) is full, and cannot store any
new messages that arrive at the Secondary.
Timeout errors
Displays the number of times that the Primary timed out while waiting for an acknowledgement from the secondary.
Missing packet errors
Displays the number of times that the last packet of a message was received before one or more packets of the same mes-
sage had been received.
Missing message errors
Displays the number of times that messages have arrived out of sequence.
Stream errors
Displays the number of times that the RLINK has attempted to send messages faster than the network can handle.
Checksum errors
Displays the number of data checksum errors. (Every time a packet is received at the secondary, VVR performs a checksum
to ensure that the packet data is the same as that sent by the Primary.)
Unable to deliver due to transaction errors
Displays the number of times that packets could not be delivered to the secondary because of transaction errors. (If
the secondary is busy with some kernel operations when a packet arrives at the secondary, the packet may not be deliv-
ered until the transaction is complete.)
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, the output shows the number of updates and blocks by which 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.
The -T option (timestamp) displays the status of the Primary showing the amount of time (as hours:minutes:seconds) by which the
given RLINK is lagging.
Note: If the Primary is up-to-date, or the RLINK is in DCM mode, the timestamp is not displayed in the output.
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.
The -T option (timestamp) displays the amount of time by which the secondary is lagging (as Mon DOM hours:minutes:seconds where
Mon is the locale-specific abbreviation of the month, and DOM is the day number in the month).
verify Displays configuration information for the rlink. Configuration update messages are sent to each secondary RLINK when appropri-
ate. 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
-a Use with the att command on the primary to attach a group of RLINKs for automatic synchronization(autosync). The autosync opera-
tion 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.
-b Use with the att command on the Bunker Primary. This option starts the replay of data from the bunker SRL to the Secondary.
-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. Similarly, the -c option is required with the checkdelete command to specify a checkpoint that is to be deleted.
-e Displays extended statistics for errors reported by the RLINK. The output includes six additional columns that provide diagnostic
information on the error conditions. This option can be used in conjunction with the -i and -t options. In a clustered environ-
ment extended statistics will be printed only on a node which is the logowner and is running the CVM protocol version 60 or
higher.
-f Use with the att command on the primary to force an attach of an rlink when the secondary data volumes are completely synchro-
nized 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.
-T For the vxrlink status command, displays the status of the Secondary image represented by the given RLINK together with a time-
stamp that indicates the amount of time by which the RLINK is lagging.
For the vxrlink updates command, displays the amount of time by which the Secondary is lagging.
-w Forces a secondary rlink into the FAIL state. Used only in special circumstances (secondary online backup). The rlink is marked
inconsistent.
EXIT CODES
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
vxdg(1M), vxedit(1M), vxintro(1M), vxmake(1M), vxplex(1M), vxprint(1M), vxrvg(1M), vxvol(1M), vradmin(1M)
VxVM 5.0.31.1 24 Mar 2008 vxrlink(1M)