System Administration Commands sndradm(1M)
NAME
sndradm - control Sun StorageTek Availability Suite Remote
Mirror operationsSYNOPSIS
sndradm -I a master shadow bitmap
sndradm -I d master shadow bitmap
sndradm -h usage message
sndradm -v version information
sndradm [options] -e [sndr_set]
sndradm [options] -E [sndr_set]
sndradm [options] -d [sndr_set]
sndradm [options] -D block [sndr_set]
sndradm [options] -D noblock [sndr_set]
sndradm [options] -l [sndr_set]
sndradm [options] -m [sndr_set]
sndradm [options] -m -r [sndr_set]
sndradm [options] -u [sndr_set]
sndradm [options] -u -r [sndr_set]
sndradm [options] -w [sndr_set]
sndradm [options] -H [sndr_set]
SunOS 5.11 Last change: 2 Oct 2007 1
System Administration Commands sndradm(1M)
sndradm [options] -p [sndr_set]
sndradm [options] -P [sndr_set]
sndradm [options] -q a volume [sndr_set]
sndradm [options] -q d [sndr_set]
sndradm [options] -q r volume [sndr_set]
sndradm [options] -i [sndr_set]
sndradm [options] -a value [sndr_set]
sndradm [options] -A value [sndr_set]
sndradm [options] -F value [sndr_set]
sndradm [options] -W value [sndr_set]
sndradm [options] -R
sndradm [options] -R b p bitmap [sndr_set]
sndradm [options] -R b s bitmap [sndr_set]
sndradm [options] -R C tag [sndr_set]
sndradm [options] -R g io_groupname [sndr_set]
sndradm [options] -R m sync [sndr_set]
sndradm [options] -R m async [sndr_set]
SunOS 5.11 Last change: 2 Oct 2007 2
System Administration Commands sndradm(1M)
sndradm [options] -R -f volset-file
sndradm [options] -R r [sndr_set] *
DESCRIPTION
The /usr/sbin/sndradm command is the administrative command
line interface for the Sun StorageTek Availability SuiteRemote Mirror software. Remote Mirror enables you to repli-
cate disks between different physically-separate Sun servers
in real time. Remote Mirror is conceptually similar to the local disk mirroring scheme of RAID 1 but it performs its replication operations over longer distances.If you do not specify a Remote Mirror set (sndr_set) on the
command line, sndradm operates on all configured Remote Mir-
ror sets.The sndradm command generates an entry in the Availability
Suite log file, /var/adm/ds.log (see ds.log(4)), for alloperations except print (-p, -P and -i), help (-h), and ver-
sion (-v).
OPTIONSThe sndradm utility supports the following options:
-f volset-file
Specifies a file containing the sndr_set information for
one or more Remote Mirror sets in the same format as thefully specified command line sndr_set documented below.
-g io_groupname
Limits operations to only those Remote Mirror setsbelonging to io_groupname.
The io_groupname for a given set must be consistent
across both the primary and the secondary hosts.-C tag
On a clustered node, limits operations to only those Remote Mirror sets belonging to the cluster resource group or disk group name specified by tag. This option is not valid on a system that is not clustered.SunOS 5.11 Last change: 2 Oct 2007 3
System Administration Commands sndradm(1M)
-n
Does not prompt the user after starting a Remote Mirroroperation using sndradm. For all but the printing, help,
and version options, the default behavior is to promptfor a response. For example, after starting a full syn-
chronization from the primary to the secondary volume,Remote Mirror prompts: "Overwrite secondary with pri-
mary? (Y/N) [N]".
sndr_set
Specifies the Remote Mirror set. For a set that hasalready been enabled, this can be a set_name in the for-
mat shost:sdev. You can supply a fully specified Remote Mirror set in the same format as a configuration file: phost pdev pbitmap shost sdev sbitmap ip {sync | async} \[g io_groupname] [C tag]
These parameters are described as follows: phost Specifies the server on which the primary volume resides. pdevSpecifies the primary volume partition to be repli-
cated. Specify full pathnames only (for example, /dev/rdsk/c0t1d0s2). pbitmap Specifies the volume partition on which the bitmap (scoreboard log) of the primary partition is stored. Specify full pathnames only (for example, /dev/rdsk/c0t1d0s3). shost Specifies the server on which the secondary volume resides. sdevSunOS 5.11 Last change: 2 Oct 2007 4
System Administration Commands sndradm(1M)
Specifies the secondary volume partition. Specify full path names only (for example, /dev/rdsk/c0t1d0s4). sbitmap Specifies the volume partition on which the bitmap (scoreboard log) of the secondary partition is stored. Specify full path names only (for example, /dev/rdsk/c0t1d0s5). ip Specifies the network transfer protocol. sync | async Specifies the Remote Mirror operating mode. sync isthe Remote Mirror mode where the I/O operation is not confirmed as complete until the remote volume has been updated. async is the Remote Mirror mode
where the primary host I/O operation is confirmed as complete before updating the remote volume.
io_groupname
Specifies the name of the Remote Mirror consistency group to which the Remote Mirror set belongs. In asynchronous mode, write ordering must be preserved across all replicating volumes in a Remote Mirror consistency group. This ensures that the secondary volumes belonging to the group contains a validpoint-in-time copy of the corresponding primary
volumes. When adding an existing set to a consistency group or when enabling a set to be in a group, the set must be configured with the same group name on both the primary and the secondary hosts. tag For operation within a cluster, this specifies the disk group name or resource tag of the local data and bitmap volumes in cases where this is not implied by the name of the volume (for example, /dev/rdsk/md/dg/vol and /dev/vx/rdsk/dg/vol bothSunOS 5.11 Last change: 2 Oct 2007 5
System Administration Commands sndradm(1M)
indicate a disk group name of dg). It is the respon-
sibility of the user to ensure that the cluster tagspecified to the Remote Mirror matches the appropri-
ate cluster resource group tag, and to keep all the Availability Suite services up to date in the event of cluster resource group reconfigurations. It is illegal to specify the cluster resource tag on a system that is not clustered.PARAMETERS
A valid sndradm command must specify one of the parameters
listed below.-I a master shadow bitmap
Add an ndr_ii entry with the specified master, shadow,
and bitmap to the Availability Suite configuration file.See sndrsyncd(1M). If the corresponding Point-in-Time
Copy set does not exist, it is enabled when the next sync command is issued on the related volume(s). When nolonger required, this Point-in-Time Copy set can be dis-
abled by iiadm -d. See iiadm(1M)
-I d master shadow bitmap
Delete the ndr_ii entry with the specified master, sha-
dow, and bitmap from the Availability Suite configura-
tion file. Use the dscfg command to list ndr_ii confi-
guration entries.-a value
Specifies the value, on or off, of the automatic sync variable for the set. Once autosync has been requested for a set, the functionality is active from the time a sync operation is requested until the set is manually put into logging mode. Once the set is manually put into logging mode, the autosync functionality is not active and remains inactive until the next time a sync request is made. To check whether autosync is active, usesndradm -P. To check whether autosync has been requested
for a set, look for the"auto=on;" tag for the set in theoutput of dscfg -l. See sndrsyncd(1M).
-A value
Specifies the maximum number of threads that can beSunOS 5.11 Last change: 2 Oct 2007 6
System Administration Commands sndradm(1M)
created to process the asynchronous queue when a set is replicating in asynchronous mode. The default is 2.-W value
Specifies the maximum number of writes that can be queued to a set replicating in asynchronous mode. The default is 4096. For example, set this value to 1 to ensure that the secondary volume is never more than one write operation behind the primary volume. Tuning the maximum number of writes is only valid forsets using memory-based async I/O queues. This value is
ignored when disk based I/O queues are used.
-D {block | noblock}
Toggles the block|noblock attribute of a disk-based
queue. The default setting is block. If the I/O fill rate is larger than the drain rate for enough time for
the queue to fill, incoming I/O is blocked until there is adequate space on the queue for it. This is to preserve write ordering whether it is one volume or across many volumes in the same consistency group. If
noblock is set, and incoming I/O fills the queue, the
I/O is not blocked. Instead, the set is put into logging and the disk queue contents are disregarded. An ensuing
update sync synchronizes the latest data to the secon-
dary site.-F value
Specifies the maximum number of 512-byte FBAs that can
be queued in kernel memory to a set replicating in asyn-
chronous mode. The default is 16384. Tuning the maximum number of FBAs is valid only for setsusing memory-based async I/O queues. This value isig-
nored when disk-based I/O queues are used.
-h
Prints the sndradm usage summary.
-v
Prints the Remote Mirror version number.SunOS 5.11 Last change: 2 Oct 2007 7
System Administration Commands sndradm(1M)
-e
Enables Remote Mirror for the set and enables scoreboard logging. The scoreboard is set to indicate that a full synchronization is required. Details of the set are saved in the current configuration. See dscfg(1M). The local volume and the bitmap volume are enabled for the Storage Volume driver (see sv(7D)).-E
Enables Remote Mirror for the set and enables scoreboard logging. The scoreboard is cleared to indicate that the primary and secondary volumes are already guaranteed to be fully synchronized. Details of the set are saved in the current configuration. See dscfg(1M). The local volume and the bitmap volume are enabled for the Storage Volume driver (see sv(7D)).-d
Disables Remote Mirror for the set and halts any currentsynchronization operations. sndradm -d also discards any
active scoreboards that track temporary differences between primary and secondary volumes.-l
Stops Remote Mirror replication and copy operations between primary and secondary volumes and starts independent Remote Mirror scoreboard logging on these volumes. When all the sets in a consistency group are replicating, it means that the secondary volumes containa valid point-in-time copy of the corresponding primary
volumes. Under this condition, as soon as one Remote Mirror set drops into logging mode, the rdc kernelmodule drops all the other sets in the group into log-
ging mode automatically. This ensures that the secondaryvolumes still contains a valid point-in-time copy. To
resume the Remote Mirror after using the -l parameter,
use the -m parameter to perform a full resynchronization
or the -u parameter to perform an update resynchroniza-
tion (based on the scoreboard). This option does not work on the secondary for any volumes that are currently synchronizing.SunOS 5.11 Last change: 2 Oct 2007 8
System Administration Commands sndradm(1M)
-w
Waits for a synchronization copy to complete or abort,or returns immediately if invoked on the secondary sys-
tem.-H
Reports on the health of the network link used by the specified volume set. The health of the link is reported as active or inactive. Active means that the networklink is actively being used for replicating or resyn-
chronizing data, and is therefore in good health. Inac-
tive means that the network link is not actively being used for replicating or resynchronizing data, which might indicate a problem with the link.-p
Displays a list of configured Remote Mirror volumes or sets.-P
Displays a list of configured Remote Mirror volumes or sets with extra details. (See state descriptions, below.)-q a volume
Add a disk queue to a set or group. This operation is valid when the set or group is in logging mode.-q d
Remove a disk queue from a set or group. This operation is valid when the set or group is in logging mode.-q r volume
Replace a disk queue for a group or set. The queue isremoved from the set or group as in the queue-disable
operation and the new disk queue is added as in thequeue-add operation. This operation is valid when the
set or group is in logging mode.SunOS 5.11 Last change: 2 Oct 2007 9
System Administration Commands sndradm(1M)
-i
Displays a list of configured Remote Mirror volumes orsets in the same format as the volset-file.
-R
Attempt to reset a Remote Mirror set's error condition such as failed bitmaps.-R b p bitmap
Reconfigure a Remote Mirror set's primary bitmap. This command should be entered on both primary and secondary servers. It is only possible to reconfigure the primary bitmap for one set at a time.-R b s bitmap
Reconfigure a Remote Mirror set's secondary bitmap. This command should be entered on both primary and secondaryservers. It is only possible to reconfigure the secon-
dary bitmap for one set at a time.-R C tag
Reconfigure the cluster tag, or disk group name, of a Remote Mirror set's local volumes, in those cases where this is not indicated by the pathname. This does not affect the remote volumes. This parameter cannot be used on a system that is not clustered.-R m {sync | async}
Reconfigure the replication mode of a Remote Mirror set. The sets belonging to a consistency group must be either all synchronous or all asynchronous. It is not possible to mix modes within a group.-R g group
Reconfigure the consistency group of a Remote Mirror set. This command should be entered with the same group name on both primary and secondary servers. To remove a set from a consistency group, specify theSunOS 5.11 Last change: 2 Oct 2007 10
System Administration Commands sndradm(1M)
null string (" ") when reconfiguring the consistency group. The following parameters can be issued only from the primary server:-m
Starts a full volume copy from the primary volume to the secondary volume, and concurrently enables Remote Mirror replication of new updates from the primary volume tothe secondary volume. Use this parameter when the pri-
mary and secondary volumes might be different and nologging information exists to incrementally resynchron-
ize the volumes. See EXIT STATUS.-r
Reverses the direction of the synchronization so the primary volume is synchronized from the secondaryvolume. Use this parameter with the -m or -u parameter.
-m -r starts a full volume copy from the secondary
(source) volume to the primary (target) volume but con-
currently enables Remote Mirror replication of newupdates from the primary (source) volume to the secon-
dary (target) volume, ensuring the volume sets remainsynchronized. Use -m -r when the primary and secondary
volume content might differ and the secondary has the desired contents, yet no logging information exists toincrementally resynchronize the volumes (using -u). -u
-r resynchronizes the primary (target) volume from the
secondary (source) volume, using the Remote Mirror scoreboard logs maintained while replication was suspended. It then resumes Remote Mirror replication of new updates from the primary volume to the secondary volume so that the volume sets remain synchronized. Quiesce the workload to the volume sets during the restore/refresh operation. This action ensures that the primary and secondary volumes match before replication of new updates resumes.-u
Updates a Remote Mirror volume set. This parameter resynchronizes a Remote Mirror volume set. Only theblocks logged as changed in the Remote Mirror score-
boards are updated. Enables Remote Mirror replication for the primary volume and also uses the Remote MirrorSunOS 5.11 Last change: 2 Oct 2007 11
System Administration Commands sndradm(1M)
scoreboard logs to start the resynchronization process so that the corresponding secondary volume matches the primary volume.States Returned from sndradm -P
The following are the states that can be returned fromsndradm -P.
volume failedAn I/O operation to the local data volume has failed bitmap failed
An I/O operation to the local bitmap volume has failed disk queue failed
An I/O operation to disk queue volume has failed need sync A sync to this volume has been interrupted. It needs to
be completed (or restored via Point-in-Time Copy). The
direction of the data flow must not be changed until one or the other is done. need reverse sync A reverse sync to this volume has been interrupted. Itneeds to be completed (or restored via Point-in-Time
Copy). The direction of the data flow must not be changed until one or the other is done. logging Incoming writes are logged in the bitmap only. Data is not replicated to the remote site. need sync, need reverse sync, and queuing are all substates of logging such that writes are logged in the bitmap, but not replicated. Queuing mode (described below) logs the writes to the bitmap, and queues the request for later replication by the async flushers.SunOS 5.11 Last change: 2 Oct 2007 12
System Administration Commands sndradm(1M)
reverse syncing A secondary to primary copy is in progress. syncing A primary to secondary copy is in progress. queuing During normal async replication using disk queues, i/o is placed on the disk queue to be replicated by the async flusher threads. In the event of a temporary link failure, the set transitions to queuing mode. The queue is not discarded, as it would be with memory based queues. Instead, data is logged in the bitmap and placedon the queue. When the link comes up, and sndradm -u is
issued, (automated by turning autosync on for the set) the flushers restarts. This preserves write ordering through a temporary link outage. If write ordering is not necessary, and only the latest data is needed, theset can be put into logging manually (sndradm -l) and an
update sync issued (sndradm -u). This action discards
the data on the queue, and fast resyncs using the bit-
map. If the queue fills before the link comes back and the update sync is issued, the queue is discarded and the set put into logging mode to avoid application hangs.EXAMPLES
Example 1 Enabling a Remote Mirror Set The following command enables a Remote Mirror asynchronous set on host example, where example is the primary host andexample-remote is the secondary host.
example% sndradm -e example /dev/rdsk/c1t0d0s1 /dev/rdsk/c1t1d0s3 \
example-remote /dev/rdsk/c2t3d0s5 /dev/rdsk/c2t4d0s5 ip async
Example 2 Adding a Disk Queue to an Asynchronous SetThe following command adds a disk queue volume to an asyn-
chronous set.SunOS 5.11 Last change: 2 Oct 2007 13
System Administration Commands sndradm(1M)
example% sndradm -q a /dev/rdsk/c1t2d0s3 \
example-remote:/dev/rdsk/c2t3d0s5
Example 3 Removing a Disk Queue from an Asynchronous Set The following command removes the disk queue volume from a set with a disk queue volume attatched to it.example% sndradm -q d example-remote:/dev/rdsk/c2t3d0s5
Example 4 Disabling a Remote Mirror Set The following command disables a Remote Mirror set enabled on host example.example% sndradm -d example-remote:/dev/rdsk/c2t3d0s5
EXIT STATUS 0 Command completed successfully. >0 An error occurred.When the -m or -u option is executed in a script, the exit
status following one of these options always returns suc-
cess, regardless of the current status of the Remote Mirror set.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 2 Oct 2007 14
System Administration Commands sndradm(1M)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| ____________________________|_____________________________|_
| Availability | storage/avs/remote-mirror, |
| | storage/avs/remote-mirror |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
SEE ALSO
dscfg(1M), sndrd(1M), sndrsyncd(1M), ds.log(4), rdc.cf(4), attributes(5), sv(7D)SunOS 5.11 Last change: 2 Oct 2007 15