iiadm(1M) System Administration Commands iiadm(1M)NAMEiiadm - command-line interface to control Sun StorageTek Availability
Suite Point-in-Time Copy operations
SYNOPSISiiadm-e {ind | shd} master_vol shadow_vol bitmap_vol
iiadm-ne ind master_vol shadow_vol bitmap_vol
iiadm [-p] [-n] {-c | -u} {s | m} volume_set
iiadm [-adDilR] volume_set
iiadm [-p] [-n] -w volume_set
iiadm [-hilLv]
iiadm-P delay units volume_set
iiadm-P volume_set
iiadm-A overflow_vol volume_set
iiadm [-OQ] overflow_vol
iiadm-E volume_set
iiadm [-IJ] volume_set bitmap
iiadm-g group_name [-aAcdDeEilLmPRuw]
iiadm [-C] cluster_tag [options]
DESCRIPTION
Point-in-Time Copy software is a point-in-time snapshot feature of the
Solaris operating system.
A Point-in-Time Copy snapshot is an instantly-available, time-fixed,
replicated view of a momentarily quiesced volume. Once a snapshot is
taken, Point-in-Time Copy software allows immediate read/write access
to both the master and shadow volume data.
Point-in-Time Copy software tracks the differences between the master
and shadow volumes (caused by writes) from the moment that the snapshot
was established. This capability allows applications accessing the mas‐
ter volume's data to move forward in time independently of applications
accessing the shadow volume's data, and vice-versa.
The Point-in-Time Copy software's tracking of differences between the
master and shadow volumes facilitates a fast resynchronization or a
full copy at a later time. The volume resynchronization can occur from
either shadow to master or master to shadow.
Instantly after the point-in-time is (re-)established (either when the
CLI prompt returns or the next shell script command is read), the mas‐
ter volume can be remounted or the applications using them can be
resumed. Also, the shadow volume can be mounted and immediately
accessed.
The iiadm command line utility performs only one action per command
invocation. Because of this, you cannot combine multiple options,
except in combination with the following overall command modifiers:
o If no action item is entered, iiadm displays the list of
Point-in-Time Copy sets (non-suspended) currently config‐
ured. If more than one action item, or an incorrectly speci‐
fied action item is entered, iiadm displays the specific
error message to stderr, followed by a brief usage summary.
o For the Point-in-Time Copy options ENABLE (-e), COPY (-c)
and UPDATE (-u), there are two associated shadow volume
selection qualifiers, {ind|dep}, that are used to specify
the type of Point-in-Time Copy volume set to create.
An independent (ind) snapshot causes Point-in-Time Copy software to
perform a full volume copy operation from the master to the shadow.
When the copy completes, the shadow volume data is identical to the
master volume data at the moment that it was established. Create an
independent shadow if you require two physical copies of the data. An
independent shadow volume must be the same size or greater than the
size of the master volume. Sun recommends that the master and shadow
volumes be the same size for environments where resynchronization from
shadow to master is a consideration.
A dependent (dep) snapshot causes Point-in-Time Copy software not to
perform a full volume copy. The resulting shadow volume relies on the
master volume for all unmodified data blocks, which are not copied
until requested. Create a dependent shadow when you do not require two
physical copies of the data. A dependent shadow volume can be either
the same size or smaller than the master volume. A smaller shadow vol‐
ume is called a Compact Dependent Shadow Volume, and is typically used
when the amount of change that occurs to a Point-in-Time Copy volume
set is small compared to the entire size of the master volume.
The following syntax allows you to create an exportable independent
shadow volume in a Sun Cluster environment:
# iiadm-ne ind master shadow bitmap
An issue arises when using a Compact Dependent Shadow Volume in that
its size is established at the time that the Point-in-Time Copy volume
set is enabled. If the amount of change to the entire volume set over
the duration of its usage exceeds the space allocated for the shadow
volume, the shadow volume is marked as out of space. It is possible to
read from the shadow volume even after it is out of space, until a por‐
tion of the data for which there was no room is requested. Once that
happens, the read fails and the shadow volume is marked offline.
To address this issue, Point-in-Time Copy supports the ability to asso‐
ciate an overflow volume to an existing Point-in-Time Copy dependent
volume set. Thus, if the size of the Compact Dependent Shadow Volume is
too small, or an unscheduled amount of change occurs to the volume set,
changed data can be redirected to the associated overflow volume. To
facilitate efficient usage of this overflow volume, it can be associ‐
ated with multiple Point-in-Time Copy volume sets on an as-needed
basis.
Considerations
Prior to invoking an Point-in-Time Copy enable, copy or update opera‐
tion, Point-in-Time Copy assures that the shadow volume is not mounted,
to prevent a file system panic from occurring. Also, it is suggested
that you either unmount or suspend (quiesce) all applications using the
master volume, for only the instant when the point-in-time snapshot is
taken. This assures that an atomically consistent point-in-time snap‐
shot is taken.
It is suggested that, if the master volume was suspended rather than
unmounted, the new point-in-time shadow volume's integrity be validated
using volume validation utilities, such as fsck(1M). The reason is that
Point-in-Time Copy has made a point-in-time copy of a mounted master
volume to an unmounted shadow volume. During the mounting of the shadow
volume, the file system detects that it is in the mounted state. Typi‐
cally this state occurs only when a system crashes, so the file system
attempts to validate the integrity of the volume assuming a system
failure occurred, not an Point-in-Time Copy.
ENVIRONMENT OPTIONS
The ii_bitmap variable in the /usr/kernel/drv/ii.conf configuration
file determines the bitmap volume operational semantics as follows:
0 Indicates that the bitmap is maintained in memory only or
resume operation.
1 Indicates that the bitmap is maintained in memory and on
disk. This is the default value.
If a system failure occurrs while using ii_bitmap=0, the shadow volume
might be inconsistent and fast resynchronization would not be possible.
If Point-in-Time Copy is used in conjunction with the Network Storage
component Remote Mirror or in a Sun Cluster, set ii_bitmap=1.
The ii_debug variable in the /usr/kernel/drv/ii.conf configuration file
determines the amount of information logging that is output to the sys‐
tem console /dev/console during Point-in-Time Copy processing.
0 Indicates that no logging is sent to the system console.
1 Indicates that informational logging is sent to the system
console.
2 Indicates that developmental logging is sent to the system
console.
OPTIONS
The iiadm utility supports the following options.
-e{ind|dep} master_vol shadow_vol bitmap_vol
Enable Point-in-Time Copy for the specified master, shadow, and
bitmap volumes.
The enable shadow set processing assures that the specified volumes
are accessible, that the shadow_vol is not mounted, and that the
bitmap_vol is correctly sized for the type of shadow set being cre‐
ated. Additionally, it assures that the volumes are under control
of the SV driver ( if they are not, it puts them there), initial‐
izes the bitmap volume, and, if the volume set is an independent
shadow set, a full copy operation is initiated.
On a successful enable, Point-in-Time Copy stores the specified
master_vol, shadow_vol and bitmap_vol names, plus the enabling type
(ind or dep), into the Point-in-Time Copy configuration store. The
configuration store contains all currently configured Point-in-Time
Copy Volume Sets and their associated configuration attributes.
(See discussion above on independent and dependent shadow volume
semantics.)
master_vol is the volume from which a point-in-time snapshot is
made.
shadow_vol is the volume that contains the point-in-time snapshot.
bitmap_vol is used for tracking differences between the shadow and
master volumes. When Point-in-Time Copy shadow operations are sus‐
pended or resumed, the bitmap volume (maintained in kernel memory)
can be stored in or retrieved from permanent storage. The storage
associated with the bitmap volume should be as redundant as that of
the shadow volume storage.
The shadow_vol name is the name that the Point-in-Time Copy Shadow
Set is known by for all iiadm options requiring specification of a
volume_set name.
-d volume_set
Disable the Point-in-Time Copy volume set associated with the spec‐
ified volume_set.
If Point-in-Time Copy was running in independent mode as specified
in the -e ind options, above, the shadow volume data contains the
same data as it did before it was disabled (assuming no writes have
occurred). Users can access the master and shadow volumes, as they
are now standalone point-in-time copies.
During the time that the full copy is active, an independent volume
operates as though it is a dependent volume. To assure that the
volume is no longer in full copy mode, issue the following command
to wait for the full copy to complete:
# iiadm-w volume_set
[-p] -u s volume_set
Update the shadow volume from the master.
Updates a point-in-time copy of the master volume to the shadow
volume. volume_set is the Point-in-Time Copy shadow set containing
the master and shadow volumes. This option provides a fast resyn‐
chronization of the shadow volume, creating an incremental copy of
the master. This update copies all 32KB segments flagged as differ‐
ent between the master and shadow volumes. It does not copy all
master volume data, only changed data. While the data is being
copied, the shadow is dependent upon the master volume.
Before using this option, momentarily quiesce the workload to the
volumes; stop the host application from writing to the volumes.
This ensures that the point-in-time data is consistent. You can
visually check the status of this copy or update operation with
iiadm-i volume_set, or interactively (by means of a shell or
script) with iiadm-w volume_set, before using the target volume
for any other operations.
This command supports PID (Process IDentifier) locking, by using
the option -p, iiadm-p -u s. Enabling this option prevents other
processes from taking a new point-in-time snapshot, thus invalidat‐
ing prior point-in-time data.
[-p] [-n] -u m volume_set
Updates a point-in-time copy of the master volume from the shadow.
volume_set is the Point-in-Time Copy volume set containing the mas‐
ter and shadow. This option provides a fast resynchronization of
the master volume, creating an incremental copy of the shadow. This
update copies all 32KB segments flagged as different between the
master and shadow volumes. It does not copy all shadow volume data,
only changed data. While the data is being copied, the master is
dependent upon the shadow volume.
Before using this option, momentarily quiesce the workload to the
volumes; stop the host application from writing to the volumes.
This ensures that the point-in-time data is consistent. You can
visually check the status of this copy or update operation with
iiadm-i volume_set, or interactively (by means of a shell or
script) with iiadm-w volume_set, before using the target volume
for any other operations.
This command is query enabled to prevent accidentally overwriting
the data on a master volume. When this command option is used in
scripts, add the -n option to prevent the query from occurring.
This command supports PID (Process IDentifier) locking, by using
the option -p, iiadm-p -u m. Enabling this option prevents other
processes from taking a new point-in-time snapshot, thus invalidat‐
ing prior point-in-time data.
[-p] -c s volume_set
Copy the master volume to the shadow.
Creates a point-in-time copy of the master volume to the shadow
volume. volume_set is the Point-in-Time Copy volume set containing
the master and shadow. This option writes all data in the point-in-
time copy of the master volume to the shadow volume. While the data
is being copied from master to shadow, the shadow is dependent on
the master volume.
This option performs a full volume copy. Use iiadm-u s unless the
integrity of the data on the independent shadow volume is in doubt.
Otherwise, use this option to synchronize the master and shadow
volumes; that is, make the data on each volume match.
Before using this option, momentarily quiesce the workload to the
volumes; stop the host application from writing to the volumes.
This ensures that the point-in-time data is consistent. You can
visually check the status of this copy or update operation with
iiadm-i volume_set, or interactively (by means of a shell or
script) with iiadm-w volume_set, before using the target volume
for any other operations.
This command supports PID (Process IDentifier) locking, by using
the -p option, iiadm-p -c s. Enabling this option prevents other
processes from taking a new point-in-time snapshot, thus invalidat‐
ing prior point-in-time data.
-c m volume_set
Copy the shadow volume to the master.
Creates a point-in-time copy of the shadow volume to the master
volume. volume_set is the Point-in-Time Copy volume set containing
the master and shadow volumes. This option writes all data in the
point-in-time copy of the shadow volume to the master volume. While
the data is being copied from the shadow to the master, the master
is dependent upon the shadow volume.
This option performs a full volume copy. Use iiadm-u m unless the
integrity of the data on the independent master is in doubt. Other‐
wise, use this option to synchronize the master and shadow volumes;
that is, make the data on each volume match.
Before using this option, momentarily quiesce the workload to the
volumes; stop the host application from writing to the volumes.
This ensures that the point-in-time data is consistent. You can
visually check the status of this copy or update operation with
iiadm-i volume_set, or interactively (by means of a shell or
script) with iiadm-w volume_set, before using the target volume
for any other operations.
This command is query-enabled to prevent accidentally overwriting
the data on a master volume. When this command option is used in
scripts, add the -n option to prevent the query from occurring.
This command supports PID (Process IDentifier) locking, by using
the -p option, iiadm-p -c m. Enabling this option prevents other
processes from taking a new point-in-time snapshot, thus invalidat‐
ing prior point-in-time data.
-a volume_set
Abort any current copy operation that might be active between the
master and shadow volumes. volume_set is the Point-in-Time Copy
volume set containing the master and shadow volumes. After execut‐
ing iiadm-a, the update or copy to the target (master or shadow)
volume is incomplete. The target volume is now a dependent copy of
the source volume. Reissue the update or copy command option to
resynchronize the volumes.
[-p] [-n] -w volume_set
Wait until any in-progress copy or update operation completes or is
aborted. volume_set is the Point-in-Time Copy volume set containing
the master and shadow volumes.
This option waits until the current Point-in-Time Copy operation is
complete, thus preventing a subsequent iiadm command (from a shell
or script) from executing. Use this command option when you need to
be sure the copy or update operation has completed.
This command supports PID (Process IDentifier) unlocking. If a
prior copy or update, using a command iiadm-p {-c|-u} {m|s}, was
invoked with the -p option, upon completion of the wait processing,
if the current PID was the PID that locked the point-in-time data,
this option unlocks the data.
-i volume_set
Display status for the Point-in-Time Copy currently-enabled or
-suspended volume set. volume_set is the Point-in-Time Copy volume
set containing the master and shadow volumes. If no volume_set is
specified, status is displayed for all Point-in-Time Copy volume
sets that are configured.
-l
List all currently configured Point-in-Time Copy volumes.
-O overflow_vol
This option causes Point-in-Time Copy to initialize the specified
overflow_vol for subsequent use as an overflow volume in conjunc‐
tion with Compact Dependent Shadow Volumes. To facilitate effi‐
cient, shared usage of this overflow volume, it can be associated
with multiple Point-in-Time Copy volume sets on an as-needed basis.
During initialization of the overflow_vol, the initiator of this
option, must answer the following question: "Initialize this over‐
flow volume? yes/no" A response of either "yes/no" is required
before proceeding.
This option supports the -n option, so that the requested action is
performed without prompting. This option is useful for inclusion in
a script. The -n option must be specified first. For example,
"iiadm -nO vol" is valid; "iiadm -On vol" is not.
Make sure you want to initialize the data on the specified over‐
flow_vol, especially when using the -n option.
-A overflow_vol volume_set
This option enables the specified overflow_vol, for subsequent use
as an overflow volume in a situation where the size of the Compact
Dependent Shadow Volume is too small, or an unscheduled amount of
change occurs to the volume set. Overflow changed data would be
redirected to the associated overflow volume. volume_set is the
Point-in-Time Copy volume set containing the master and shadow vol‐
umes.
If the overflow_vol has not been initialized, this option initial‐
izes the overflow_vol (see -O option), then attaches the over‐
flow_vol to the volume_set.
If overflow_vol was previously initialized, this option attaches
the overflow_vol to the volume_set.
This option supports the -n option, so that the requested action is
performed without prompting. This option is useful for inclusion in
a script. The -n option must be specified first. For example,
"iiadm -nA vol" is valid; "iiadm -An vol" is not.
Make sure you want to initialize the data on the specified over‐
flow_vol, especially when using the -n option.
-D volume_set
This option removes the overflow volume currently associated with
the specified volume_set. If the overflow volume is currently in
use by the volume_set, this operation fails with an "Overflow vol‐
ume still in use" error message. To resolve this situation, perform
one of the operations described below on the volume_set. These
operations momentarily clear out all overflow writes that are asso‐
ciated with this volume set.
abort(-a)
Abort copy operation.
disable(-d)
Dissolve the volume set.
update(-u)
Update the volume set.
-L
This option lists all overflow volumes which are associated with
one or more volume sets.
-Q overflow_vol
This option displays the current status of the overflow_vol.
-E volume_set
Export the independent shadow volume of the Point-in-Time Copy vol‐
ume set specified by volume_set. The shadow volume is to be made
available to another host for read/write access, by means of an
enabling technology, such as multi-ported devices. This other host
is responsible for maintaining a bitmap of differences that is used
to merge with locally recorded differences to the master when the
shadow volume is rejoined to its master volume. While a shadow vol‐
ume is exported it must not be subject to an update or copy opera‐
tion. Perform an iiadm-w volume_set command prior to invoking an
export command.
-I volume_set bitmap_vol
Import the independent shadow volume of the Point-in-Time Copy vol‐
ume set specified by volume_set. The shadow volume must have been
previously exported from a host by means of an enabling technology,
such as multi-ported devices. The import operation causes this host
to start maintaining a bitmap of differences as the volume is modi‐
fied. The bitmap_vol should not be the same as that used when the
shadow volume was originally formed into a shadow group.
After the exported/imported independent shadow volume is no longer
needed by the other node, you must enter a disable command so that
the bitmap_vol and its associated shadow_vol are consistent, prior
to performing a join operation. For example,
# iiadm-d volume_set
-J volume_set bitmap_vol
Join the volume_set, using the bitmap_vol, with the master volume
set of the Point-in-Time Copy volume set. The bitmap volume sup‐
plied is read and merged with the original volume to reconstruct
the original volume set consisting of the master, shadow, and bit‐
map volumes. The bitmap_vol to be merged is the one obtained on the
node that had imported the independent shadow volume. There must be
no write activity to the shadow volume on the importing machine
from the time the bitmap is copied over until the shadow is once
again imported.
-g group_name -m volume_set [volume_set2 ...]
Add one or more existing Point-in-Time Copy volume_set(s) into a
user specified group_name. This association of one or more Point-
in-Time Copy volume sets in a group allows the list of iiadm
options shown below to be performed on all volume sets within the
group_name as a whole.
Only the commands COPY (-c) and UPDATE (-u) are performed atomi‐
cally across all Point-in-Time Copy sets within the group. All
other grouped, iiadm commands are performed sequentially on each
member of the group.
The syntax of an iiadm group command is as follows:
iiadm-g group_name [options]
The options are as follows:
-a
Abort copy operation on all sets within group_name.
-A
Attach overflow_vol to all sets within group_name.
-c {s | m}
Copy shadow/master for all sets within group_name.
-D
Detach overflow_vol from all sets within group_name.
-d
Disable all sets within group_name.
-E
Export all volume sets within group_name.
-i
Status of all volume sets within group_name.
-l
List all volume sets within group_name.
-L
List all groups.
-n
Do not ask if an update of the master volume is what the user
really intended.
-P
Set parameters on all volume sets within group_name.
-R
Reset all volume sets within group_name.
-u {s | m}
Update shadow/master for all sets within group_name.
-w
Wait for all volume sets within group_name.
-g -" " -m volume_set [volume_set2 ...]
Remove one or more existing Point-in-Time Copy volume_set(s) from
their currently associated group_name. By default, or until moved
into a user specified group_name, all Point-in-Time Copy vol‐
ume_set(s) are in the blank (" ") group. This association allows
all the previously documented iiadm group commands to be performed
against the blank (" ") iiadm group_name.
-C cluster_tag
This Point-in-Time Copy option is a modifier that limits configura‐
tion operations to only those volumes belonging to a Sun Cluster
Resource Group, or Disk Group.
In a Sun Cluster where the volume manager is Sun Cluster-aware,
iiadm automatically obtains the correct Disk Group information,
therefore this option is typically not required unless the volumes
are part of an encompassing Resource Group.
In a Sun Cluster where the volumes are accessible on the local node
only, the special cluster_tag of local is used to indicate volumes
that are not part of a Sun Cluster Resource Group or Disk Group.
If "-L" is given as a the cluster_tag argument, then iiadm lists
all cluster tags associated with Point-in-Time Copy.
This option is invalid when used on a Solaris system on which the
Sun Cluster package has not been installed or configured.
-h
Prints the iiadm usage summary.
-v
Display the current version of the Point-in-Time Copy software com‐
ponents.
Contact Sun Enterprise Services for assistance in using the remaining
commands in this section.
-P delay unit volume_set
Alter the Point-in-Time Copy volume set tuning parameters for the
specified volume_set to delay ticks, every unit I/O's. Delay ranges
from 2 to 10000 inclusive; unit ranges from 100 to 60000 inclusive.
-R volume
After a volume has failed, Point-in-Time Copy places it offline.
After replacing the volume, place it back online using this option.
Associated dependent volumes in the Point-in-Time Copy volume set
are also placed online. After the volume is placed online, this
command also starts any necessary point-in-time volume updates.
EXIT STATUS
0 Command completed successfully.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬────────────────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼────────────────────────────────────────┤
│Availability │storage/avs/point-in-time-copy, SUNWiiu │
├─────────────────────────────┼────────────────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴────────────────────────────────────────┘
SEE ALSOdscfg(1M), svadm(1M), ds.log(4), rdc.cf(4), attributes(5), ii(7D),
sv(7D)SunOS 5.11 2 Oct 2007 iiadm(1M)
