4 Creating LSM Disk Groups and Volumes

An LSM volume is an object that represents a hierarchy of LSM objects that allocates space to, and stores data for, a file system or application. You create an LSM volume differently depending on whether the volume is for a new file system or application or an existing file system or application.

This chapter describes how to:

Create a disk group and check a disk group for space (Section 4.1)

Create an LSM volume for new data (Section 4.2)

Configure UFS or AdvFS file systems to use an LSM volume (Section 4.3)

Create an LSM volume for existing data (Section 4.4)

Use the information from the worksheets you filled out in Chapter 2 to create disk groups and LSM volumes.

4.1 Creating Disk Groups

You must create an LSM volume in a disk group. By default, LSM creates volumes in the rootdg disk group, which was created when you installed LSM. You can create all LSM volumes in the rootdg disk group or you can create other disk groups. The following sections describe how to:

Display disk group information

Create a disk group

Add disks to a disk group

Create a backup copy of the disk label information

4.1.1 Displaying Disk Group Information

To display information about the rootdg disk group and other disk groups, enter:

# voldisk list

Information similar to the following is displayed:

DEVICE       TYPE      DISK         GROUP        STATUS  
dsk0         sliced    -            -            unknown  
dsk1         sliced    -            -            unknown  
dsk2         sliced    dsk2         rootdg       online  
dsk3         sliced    dsk3         rootdg       online  
dsk4         sliced    dsk4         rootdg       online  
dsk5         sliced    dsk5         rootdg       online  
dsk6         sliced    dsk6         dg1          online  
dsk7         sliced    dsk7         dg1          online  
dsk8         sliced    -            -            unknown

where:

`DEVICE`	Specifies the disk access name assigned by the operating system software.
`TYPE`	Specifies the LSM disk type: sliced, simple, or nopriv.
`DISK`	Specifies the LSM disk media name. An LSM disk media name displays only if the disk is in a disk group.
`GROUP`	Specifies the disk group to which the device belongs. A group name displays only if a disk is in a disk group.
`STATUS`	Specifies the status of the LSM device. The status is one of the following: `online`--The device was initialized for LSM use and is in use. `offline`--The device was initialized for LSM use, but is not available. `unknown`--LSM detected the device, but it was not initialized for LSM use (has no disk media name and is not part of a disk group). `error` -- The disk is detected but has experienced I/O errors. `failed was` -- An LSM disk media name exists but the disk is not associated with a `DEVICE`. Displays the last device associated with this name.

To display the total usable space in a disk group, enter:

# volassist [-g disk_group] maxsize

The following command line displays the available space in a disk group called dg1:

# volassist -g dg1 maxsize

Information similar to the following is displayed:

Maximum volume size: 6139904 (2998Mb)

4.1.2 Creating a Disk Group or Adding Disks to a Disk Group

The voldiskadd script is an interactive script that lets you:

Initialize disks or disk partitions for exclusive use by LSM

Create a disk group

Add disks to a disk group

Note

By default, LSM initializes each disk with one copy of the configuration database. If a disk group will have fewer than four disks, you should initialize each disk to have two copies of the disk group's configuration database to ensure that the disk group has multiple copies in case one or more disks fail. You must use the voldisksetup command to initialize disks with more than one copy of the configuration database. See Section 5.1.1 for more information.

If you specify an uninitialized disk, LSM initializes the disk as an LSM sliced disk. If you specify a partition name, LSM initializes the partition as an LSM simple disk. You can specify several disks and disk partitions at once, separated by a space; for example:

# voldiskadd dsk3 dsk4a dsk5 dsk6g

After you initialize a disk or disk partition, LSM writes a new disk label and the disk or disk partition becomes an LSM disk for exclusive use by LSM.

The voldiskadd script prompts you for the following information:

A disk group name
If you are creating a disk group, the disk group name must be unique and can contain up to 31 alphanumeric characters that cannot include spaces or the forward slash ( / ).

A disk media name for each disk you configure in the disk group
You can use the default disk media name or you can assign a disk media name of up to 31 alphanumeric characters that cannot include spaces or the forward slash ( / ).

Whether the disk should be a spare disk for the disk group
A spare disk is a disk initialized by LSM, but used only as a replacement disk if a disk that contains a mirror or RAID 5 plex fails. See Section 3.4.4 for more information about how LSM uses spare disks. For the best protection, configure at least one spare disk in each disk group that contains mirror or RAID 5 plexes.

The following example uses a disk called dsk9 to create a disk group called dg1:

# voldiskadd dsk9

Information similar to the following is displayed:

Add or initialize disks
 
Menu: VolumeManager/Disk/AddDisks
 
  Here is the disk selected.
 
  dsk9
 
Continue operation? [y,n,q,?] (default: y) y
 
  You can choose to add this disk to an existing disk group, a
  new disk group, or leave the disk available for use by future
  add or replacement operations. To create a new disk group,
  select a disk group name that does not yet exist. To leave
  the disk available for future use, specify a disk group name
  of "none".
 
Which disk group [<group>,none,list,q,?] (default: rootdg) dg1
 
  There is no active disk group named dg1.
 
Create a new group named dg1? [y,n,q,?] (default: y) y
 
  The default disk name that will be assigned is:
 
  dg101
 
Use this default disk name for the disk? [y,n,q,?] (default: y) y
 
Add disk as a spare disk for dg1? [y,n,q,?] (default: n) n
 
  A new disk group will be created named dg1 and the selected disks
  will be added to the disk group with default disk names.
  dsk9
 
Continue with operation? [y,n,q,?] (default: y) y
 
  The following disk device has a valid disk label, but does 
  not appear to have been initialized for the Logical Storage 
  Manager. If there is data on the disk that should NOT be 
  destroyed you should encapsulate the existing disk partitions 
  as volumes instead of adding the disk as a new disk.
 
  dsk9
 
Initialize this device? [y,n,q,?] (default: y) y
 
  Initializing device dsk9.
 
  Creating a new disk group named dg1 containing the disk
  device dsk9 with the name dg101.
 
Goodbye.

4.1.3 Creating a Backup Copy of the Disk Label Information

It is highly recommended that you create a backup copy of the updated disk label information for each LSM disk.

Having this information will simplify the process of replacing a failed disk, by allowing you to copy the failed disk's attributes to a new disk. Once a disk fails, you cannot read its disk label, and you cannot copy that information to a new disk.

To create a file that contains a backup copy of the disk label information, enter:

# disklabel dskn > file

See the disklabel(8) reference page for more information on the disklabel command.

4.2 Creating an LSM Volume for New Data

To create an LSM volume for a new file system or application, use the volassist command. The volassist command finds the necessary space within the disk group and creates all the objects for the volume. You must specify a volume name and length (size) on the command line.

You can specify values for other LSM volume attributes on the command line or in a text file that you create. If you do not specify a value for an attribute, LSM uses a default value.

To display the default values for volume attributes, enter:

# volassist help showattrs

Information similar to the following is displayed:

#Attributes:
 layout=nomirror,nostripe,span,nocontig,raid5log,noregionlog,diskalign,nostorage
 mirrors=2 columns=0 nlogs=1 regionlogs=1 raid5logs=1
 min_columns=2 max_columns=8
 regionloglen=0 raid5loglen=0 logtype=region
 stripe_stripeunitsize=64 raid5_stripeunitsize=16
 usetype=fsgen diskgroup= comment="" fstype=
 user=0 group=0 mode=0600
 probe_granularity=2048
 alloc=
 wantalloc=
 mirror=

Some volume attributes have several options to define them. Some options define an attribute globally, while others define an attribute for a specific plex type. For example, you can specify the size of a stripe data unit using the stripeunit option for both striped or RAID 5 plexes, the stripe_stripeunitsize option for striped plexes, or the raid5_stripeunitsize option for RAID 5 plexes.

See the volassist(8) reference page for a complete list of attributes. Table 4-1 describes some of the common attributes for which you can specify a value.

Table 4-1: Common LSM Volume Attributes

Attribute Description	Attribute Options
Plex type	`layout={concatenated\|striped\|raid5}`
Usage type	`-U {fsgen\|raid5\|gen}`
Whether or not to create mirrors, and if so how many	`mirror={number\|yes\|no}`
Whether or not to use a Dirty Region Log (DRL) plex for mirrored plexes	`logtype={drl\|none}`
Size of the stripe width for a striped or RAID 5 plex	`stripeunit=data_unit_size`
Number of columns for a striped or RAID 5 plex	`nstripe=number_of_columns`

Creating a text file that specifies many of these attributes is useful if you create many LSM volumes that use the same nondefault values for attributes. Any attribute that you can specify on the command line can be specified on a separate line in the text file. By default, LSM looks for the /etc/default/volassist file when you create an LSM volume. If you created an /etc/default/volassist file, LSM creates each volume using the attributes that you specify on the command line and in the /etc/default/volassist file.

Example 4-1 shows a text file called /etc/default/volassist that creates an LSM volume using a four-column striped plex with two mirrors, a stripe width of 32 KB, and no log.

Example 4-1: LSM Volume Attribute Defaults File

# LSM Vn.n
# volassist defaults file. Use '#' for comments
# number of stripes
nstripe=4
# layout
layout=striped
# mirroring
nmirror=2
# logging
logtype=none
# stripe size
stripeunit=32k

For example, to create an LSM volume using the attributes in the /etc/default/volassist file, enter:

# volassist make volume length

To specify a file other than the /etc/default/volassist file, you must use the volassist command with the -d option followed by the name of the file. If you use the -d option, LSM creates the volume using the attributes that you specify on the command line and in the named file.

For example, to create an LSM volume using the attributes in a file other than the /etc/default/volassist file, enter:

# volassist make volume length -d filename

The following lists the order in which LSM assigns values to attributes:

Values on the command line

Values in a file that you specify by using the volassist -d option

Values in the /etc/default/volassist file

Default values

4.2.1 Creating an LSM Volume Using a Concatenated Plex

Creating an LSM volume that uses a concatenated plex can be a multiple-step process. Step 1 is required, and the others are required only if you want to mirror the plex. To increase performance for mirror plexes, you can specify the disks for the data plexes and the DRL plex to ensure that LSM creates these plexes on different disks, preferably on different buses.

To create an LSM volume that uses a concatenated plex:

Create a volume with a single plex, optionally specifying disks:
```
# volassist [-g disk_group] make volume length [disks]
```
The following example creates a 3 GB volume called vol2 that uses disks dsk2, dsk3, and dsk4 in a disk group called dg1:
```
# volassist [-g dg1] make vol2 3g dsk2 dsk3 dsk4
```
The volume is created and started. If you want to mirror the plex, continue with step 2.

Add a mirror plex to the volume, specifying disks not used in the first data plex and preferably on different buses.
You can use the init=active option to prevent LSM from synchronizing the plexes. Plex synchronization is not necessary because the volume does not yet contain any data. Use this option only if the application that will use the volume always writes a block before it reads from that block.
```
# volassist [-g disk_group] mirror volume [init=active] \
layout=nolog disks
```
The following example creates a mirror plex for the same volume, using disks dsk5, dsk6, and dsk7:
```
# volassist -g dg1 mirror vol2 init=active \
layout=nolog dsk5 dsk6 dsk7
```
Note

Because two plexes are used in the volume, 6 GB of free space is needed. Each plex uses 3 GB of disk space.

Add a DRL plex to the volume, specifying a disk that is not used by one of the data plexes:
```
#  volassist addlog volume disk
```
The following example adds a DRL plex to vol2 on a disk called dsk10:
```
#  volassist addlog vol2 dsk10
```
The volume is ready for use.

4.2.2 Creating an LSM Volume Using a Striped Plex

Creating an LSM volume that uses a striped plex can be a multiple-step process, depending on whether you want mirrors and a DRL. Step 1 creates a volume with one plex, and the next steps add a mirror and a DRL to the volume. To increase performance for the volume, you can specify the disks for each plex to ensure that LSM creates these plexes on different disks, preferably on different buses.

Note

In general, you should not use LSM to stripe data if you also use a hardware controller to stripe data. In some specific cases such a configuration can improve performance but only if:

Most of the volume I/O requests are large (>= 1 MB).

The LSM volume is striped over multiple RAID sets on different controllers.

The LSM stripe size is a multiple of the full hardware RAID stripe size.

The number of LSM columns in each plex in the volume should be equal to the number of hardware RAID controllers. See your hardware RAID documentation for information about how to choose the best number of columns for the hardware RAID set.

By default, the volassist command creates columns for a striped plex on disks in alphanumeric order, regardless of their order on the command line.

To improve performance, you might want to create columns using disks on different buses. See Section 4.2.3 for more information about specifying the disk order for columns in a striped plex.

To create an LSM volume that uses striped plexes:

Create a volume with a single plex, optionally specifying disks, preferably on different buses:
```
# volassist [-g disk_group] make volume length \
layout=stripe [nstripe=number_of_columns] \
[stripeunit=data_unit_size] [disks]
```
The following example creates a 4 GB volume called vol_stripe that uses disks dsk2, dsk3 and dsk4 to create a three-column striped plex in a disk group called dg1:
```
# volassist -g dg1 make vol_stripe 4g \
layout=stripe nstripe=3 dsk2 dsk3 dsk4
```
The volume is created and started. If you want to add a mirror plex, continue with step 2.

Add a mirror plex to the volume, specifying disks not used in the first data plex and preferably on a different bus.
You can use the init=active option to prevent LSM from synchronizing the plexes. Plex synchronization is not necessary because the volume does not yet contain any data. Use this option only if the application that will use the volume always writes a block before it reads from that block.
```
# volassist [-g disk_group] mirror volume \
[init=active] layout=nolog disks
```
The following example creates a mirror plex for the volume vol_stripe, using disks dsk5, dsk6, and dsk7:
```
# volassist -g dg1 mirror vol_stripe \
init=active layout=nolog dsk5 dsk6 dsk7
```
Note

Because two plexes are used in the volume, 8 GB of free space is needed. Each plex uses 4 GB of disk space.

Add a DRL plex to the volume, specifying a disk that is not used by one of the data plexes:
```
# volassist addlog volume disk
```
The following example adds a DRL plex to vol_stripe on a disk called dsk10:
```
# volassist addlog vol_stripe dsk10
```
The volume is ready for use.

4.2.3 Creating an LSM Volume Using a Striped Plex (on Different Buses)

By default, LSM creates columns for a striped plex on the first available disks it finds in the disk group. This might result in a volume with columns that use disks on the same bus.

You can improve performance by creating a striped plex with columns that use disks on different buses. To do so, you must create the subdisks for each column.

Note

Each column of subdisks should be the same size and be a multiple of the data unit size so there is no wasted space. For example, a data unit size (stripe width) of 64 KB for a striped plex corresponds to 128 blocks (sectors), so the total of the subdisks in each column should be a multiple of 128.
If each column comprises one subdisk (the typical configuration), then the subdisk size should be a multiple of 128. If a column comprises two subdisks, one subdisk can be one sector and the other can be 127 sectors, both could be 64 sectors, or any other combination as long as the total is a multiple of 128. In the following example, there is one subdisk per column.

To create an LSM volume that uses a striped plex on different buses:

Create the subdisks on disks on different buses:

# volmake [-g disk_group] sd subdisk disk len=length

The following example creates subdisks on disks dsk2 and dsk3 (on bus 1), dsk4 and dsk5 (on bus 2), and dsk6 and dsk7 (on bus 3):

# volmake sd dsk2-01 dsk2 len=16m
# volmake sd dsk3-01 dsk3 len=16m
# volmake sd dsk4-01 dsk4 len=16m
# volmake sd dsk5-01 dsk5 len=16m
# volmake sd dsk6-01 dsk6 len=16m
# volmake sd dsk7-01 dsk7 len=16m

Create a striped plex, specifying the order of subdisks on which to create the columns:
```
# volmake [-g disk_group] plex plex layout=stripe \
stwidth=data_unit_size sd=subdisk,...
```
The following example uses the subdisks created in step 1 and lists them in alternating bus order to create a six-column striped plex called plex_01. The command line lists the subdisks in a pattern that alternates the bus order from bus 1 to 2, then bus 1 to 3, then bus 2 to 3:
```
# volmake plex plex_01 layout=stripe stwidth=64 \
sd=dsk2-01,dsk4-01,dsk3-01,dsk6-01,dsk5-01,dsk7-01
```

If you want to create a mirror plex and a DRL for the volume, complete this step. If the volume will have only one data plex, go to step 4.
1. Repeat step 1 to create subdisks on a different group of disks on different buses for the second data plex.
  The following example creates subdisks for the columns in the second data plex on disks dsk8 and dsk9 (on bus 4), dsk10 and dsk11 (on bus 5), and dsk12 and dsk13 (on bus 6):
```
# volmake sd dsk8-01 dsk8 len=16m
# volmake sd dsk9-01 dsk9 len=16m
# volmake sd dsk10-01 dsk10 len=16m
# volmake sd dsk11-01 dsk11 len=16m
# volmake sd dsk12-01 dsk12 len=16m
# volmake sd dsk13-01 dsk13 len=16m
```
2. Repeat step 2 to create the second data plex, specifying the order of subdisks on which to create the columns.
  The following example uses the subdisks created in step 3a and lists them in alternating bus order to create a six-column striped plex called plex_02. The command line lists the subdisks in a pattern that alternates the bus order from bus 4 to 5, then bus 4 to 6, then bus 5 to 6:
```
# volmake plex plex_02 layout=stripe stwidth=64 \
sd=dsk8-01,dsk10-01,dsk9-01,dsk12-01,dsk11-01,dsk13-01
```

Create the LSM volume, specifying the name of the data plex you created in step 2, and the additional data plex (if any) you created in step 3:
```
# volmake [-g disk_group] -U usage_type vol volume \
plex=plex ...
```
The following example creates an LSM volume called vol9 with a usage type of fsgen, using a plex called plex_stripe:
```
# volmake -U fsgen vol vol9 plex=plex_stripe
```
The following example creates an LSM volume called vol_mirr with a usage type of fsgen, using data plexes called plex_01 and plex_02:
```
# volmake -U fsgen vol vol_mirr plex=plex_01,plex_02
```

If the volume has mirror plexes, add a DRL plex to the volume on a disk that is not used by one of the data plexes:
```
# volassist addlog volume disk
```

Start the LSM volume:
```
# volume start volume
```
The volume is ready for use.

4.2.4 Creating an LSM Volume Using a RAID 5 Plex

By default, the volassist command creates columns for a RAID 5 plex on disks in alphanumeric order, regardless of their order on the command line.

To improve performance, you might want to create the columns on disks on different buses. See Section 4.2.5 for more information about specifying the disk order for columns in a RAID 5 plex.

The volassist command automatically creates a RAID 5 log plex for the volume.

To create an LSM volume that uses a RAID 5 plex, enter:

# volassist [-g disk_group] make volume length layout=raid5 \
[nstripe=number_of_columns] [stripeunit=data_unit_size] [disks]

The following example creates a 6 GB, six-column volume called vol6 in a disk group called dg1, using any available disks:

# volassist -g dg1 make vol6 6g layout=raid5 nstripe=6

4.2.5 Creating an LSM Volume Using a RAID 5 Plex (on Different Buses)

By default, LSM creates columns for a RAID 5 plex on the first available disks it finds in the disk group. This might result in a volume with columns that use disks on the same bus.

You can improve performance by creating a RAID 5 plex with columns that use disks on different buses. To do so, you must create the subdisks for each column.

Note

Each column of subdisks should be the same size and be a multiple of the data unit size so there is no wasted space. For example, a data unit size (stripe width) of 16 KB for a RAID 5 plex corresponds to 32 blocks (sectors), so the total of the subdisks in each column should be a multiple of 32.
If each column comprises one subdisk (the typical configuration), then the subdisk size should be a multiple of 32. If a column comprises two subdisks, one subdisk can be one sector and the other can be 31 sectors, both could be 16 sectors, or any other combination as long as the total is a multiple of 32. In the following example, there is one subdisk per column.

To create an LSM volume that uses a RAID 5 plex on different buses:

Create the subdisks on disks on different buses:
```
# volmake [-g disk_group] sd subdisk disk,offset,length 
```
The following example creates 1 MB subdisks for the data plex on disks called dsk6, dsk7, dsk8, and dsk9. In this example, disks dsk6 and dsk7 are on bus 1, and dsk8 and dsk9 are on bus 2:
```
# volmake sd dsk6-01 dsk6 len=1m
# volmake sd dsk7-01 dsk7 len=1m
# volmake sd dsk8-01 dsk8 len=1m
# volmake sd dsk9-01 dsk9 len=1m
```

Create the RAID 5 data plex, specifying the order of subdisks on which to create the columns:
```
# volmake [-g disk_group] plex plex layout=raid5 \
stwidth=data_unit_size sd=subdisk,...
```
The following example uses the subdisks created in step 1 to create a four-column RAID 5 data plex called plex-01:
```
# volmake plex plex-01 layout=raid5 stwidth=16 \
sd=dsk6-01,dsk8-01,dsk7-01,dsk9-01
```
Note that in this plex, the stripe alternates between subdisks on buses 1 and 2.

Create the LSM volume, specifying the data plex:
```
# volmake [-g disk_group] -U raid5 vol volume plex=plex
```
The following example creates an LSM volume called vol5 using the plex called plex-01:
```
# volmake -U raid5 vol vol5 plex=plex-01
```

Add a RAID 5 log plex to the volume, on a disk that is not used by the data plex:
```
# volassist addlog volume disk
```

Start the LSM volume:
```
# volume start volume
```
The volume is ready for use.

4.2.6 Creating an LSM Volume for Secondary Swap Space

If disk errors occur in the swap space, a system crash is likely to occur. You can create an LSM volume using mirrored concatenated plexes to protect against disk I/O errors in the secondary swap space. Do not create a DRL plex for swap volumes, because mirror resynchronization is not necessary, and a DRL plex on swap volumes will interfere with crash dumps.

To create an LSM volume for the secondary swap space:

Create an LSM volume without a log:

# volassist [-g disk_group] -U gen make volume length \ 
nmirror=n layout=nolog

The following example creates an LSM volume called vol_swap2 that uses two mirrors with no log:

# volassist -U gen make vol_swap2 128m nmirror=2 layout=nolog

Set the LSM volume with the start_ops=norecov option so LSM does not resynchronize the mirrors:
```
# volume set start_opts=norecov volume
```

Add the LSM volume as secondary swap space using the swapon command:
```
# swapon /dev/vol/volume
```

Add the LSM device special file to the swapdevice kernel attribute value within the vm: section of the /etc/sysconfigtab file. The following example shows the entry to change:
```
vm: 
swapdevice=/dev/disk/dsk1b, /dev/vol/volume
```

See the System Administration manual and the swapon(8) and sysconfig(8) reference pages for more information on adding additional swap space.

4.3 Configuring File Systems to Use LSM Volumes

After you create an LSM volume, you use it the same way you would use a disk partition. Because LSM uses the same interfaces as disk device drivers, you can specify an LSM volume in any operation where you can specify a disk or disk partition.

The following sections describe how to configure AdvFS and UFS to use an LSM volume.

4.3.1 Creating an AdvFS Domain on an LSM Volume

AdvFS treats LSM volumes as it does any other storage device. See AdvFS Administration for information on creating an AdvFS domain.

Note

You can add more LSM volumes to an existing AdvFS domain if the domain needs more storage by creating a new LSM volume and using the AdvFS addvol command to add the volume to the domain. See AdvFS Administration for more information.

4.3.2 Creating a UFS File System on an LSM Volume

To create a UFS on an LSM volume:

Create a UFS using the LSM disk group and volume name:
```
# newfs [options] /dev/rvol/disk_group/volume
```
The following example creates a UFS on an LSM volume called vol_ufs in the dg1 disk group:
```
# newfs /dev/rvol/dg1/vol_ufs
```
It is not necessary to specify the name of the disk group for LSM volumes in the rootdg disk group.
See the newfs(8) reference page for information on newfs options.

Use the LSM block special device name to mount the file system:
```
# mount /dev/vol/disk_group/volume /mount_point
```
The following example mounts the LSM volume called vol_ufs as mnt2:
```
# mount /dev/vol/dg1/vol_ufs /mnt2
```

4.4 Creating an LSM Volume for Existing Data

When you create an LSM volume for existing data on a disk or partition, LSM:

Converts the disk or partition to an LSM nopriv disk

Encapsulates the data in the disk or disk partition

Configures the disk or disk partition into an LSM volume in the rootdg disk group

You can encapsulate data in:

Disks or disk partitions, including UFS file systems (Section 4.4.1)

AdvFS domains (Section 4.4.2)

The boot disk (Section 3.4.3)

4.4.1 Creating a Volume from Disks or Disk Partitions

The encapsulation procedure configures disks and disk partitions, which can contain any kind of data including a UFS file system, into LSM nopriv disks using information in the disk label and in the /etc/fstab file. After the encapsulation, entries in the /etc/fstab file or in the /etc/sysconfigtab file are changed to use the LSM volume name instead of the block device name of the disk or disk partition.

If you encapsulate an entire disk (by not specifying a partition letter), such as dsk3, all the in-use partitions are encapsulated as one LSM nopriv disk.

To encapsulate a disk or disk partition:

Back up the data on the disk or disk partition to be encapsulated.

Unmount the disk or partition or take the data off line. If you cannot unmount the disk or partition or take the data off line, you must restart the system to complete the encapsulation procedure.

Create the LSM encapsulation script:
```
# volencap [-g disk_group] {disk|partition}
```
The following example creates an encapsulation script for a disk called dsk3:
```
# volencap dsk3
```
Note

Although you can encapsulate several disks or disk partitions at the same time, it is recommended that you encapsulate each disk or disk partition separately.

Complete the encapsulation process:
```
# volreconfig
```
If the encapsulated disk or disk partition is in use, the volreconfig command prompts you to restart the system.

Optional but recommended, move the volume off the nopriv disks to simple or sliced disks in the same disk group. See Section 5.1.6 for more information.

4.4.2 Creating a Volume from an AdvFS Domain

You can place an existing AdvFS domain into an LSM volume by either encapsulating the domain or migrating the domain to an LSM volume:

Encapsulating the domain creates an LSM volume on the same disk or disks that the domain already uses.
- If an AdvFS domain consists of one disk or partition, you can encapsulate the disk or partition using the procedure described in Section 4.4.1.
- If the AdvFS domain consists of multiple disks or partitions (requires the AdvFS Utilities License), you can encapsulate the AdvFS domain instead of the individual disk or partitions.
LSM creates an LSM volume for each AdvFS disk or partition in the domain.
Encapsulating a domain might require restarting the system if you cannot unmount the filesets before performing the encapsulation.

Migrating the domain creates an LSM volume on disks that you specify, moves the domain data to the new volume, and removes the domain from its original disks. The disks are no longer in use by the domain after the migration completes.
This operation does not require you to unmount filesets or restart the system, but temporarily uses additional disk space until the migration is complete.

When you encapsulate an AdvFS domain, LSM changes the links in the /etc/fdmns directory to point to the LSM volumes.

No mount point changes are necessary during encapsulation or migration, because the mounted filesets are abstractions to the domain. The domain can be activated normally after the encapsulation or migration process completes. Once the domain is activated, the filesets remain unchanged and the encapsulation or migration is transparent to AdvFS domain users.

4.4.2.1 Encapsulating an AdvFS Domain

To encapsulate an AdvFS domain:

Back up the data in the AdvFS domain with the vdump utility.

Unmount all filesets.
If the domain is in use (you cannot unmount the filesets), you can create the encapsulation script and run volreconfig when convenient to complete the encapsulation procedure.

Create the LSM encapsulation script:
```
# volencap domain
```
The following example creates an encapsulation script for an AdvFS domain called dom1:
```
# volencap dom1
```

Complete the encapsulation procedure:
```
# volreconfig
```
If the AdvFS domain is mounted, the volreconfig command prompts you to restart the system.
The /etc/fdmns directory is updated on successful creation of LSM volumes.

4.4.2.2 Migrating an AdvFS Domain

You can place any AdvFS domain (except for the root_domain) into an LSM volume.

Note on TruClusters

See the Cluster Administration manual for information on migrating an AdvFS domain in a cluster.

This operation uses a different disk than the disk on which the domain originally resides and therefore does not require a restart. You can specify:

The name of the volume (default is the name of the domain with the suffix vol)

The number of stripes and mirrors that you want the volumes to use
Striping improves read performance, and mirroring ensures data availability in the event of a disk failure.

You must specify LSM disks by their disk media names to create the volume for the domain. The disks that you specify must belong to the same disk group, because LSM volumes can use disks from only one disk group. There must be sufficient LSM disks and the disks must be large enough to contain the domain. See the volmigrate(8) reference page for more information on disk requirements and the options for striping and mirroring.

To migrate a domain into an LSM volume, enter:

# volmigrate [-g diskgroup] [-m num_mirrors] [-s num_stripes] domain disk_media_name ...

The volmigrate command creates a volume with the specified characteristics, moves the data from the domain into the volume, removes the original disk or disks from the domain, and leaves those disks unused. The volume is started and ready for use, and no restart is required.