Guidelines for creating volumes

Required information to create a volume

When you create a volume to store LUNs, you must specify its name and the number of disks to be used to create it.

The capacity and the number of disks you specify determine the size of the volume. For example, if you have 72-GB disks and you use seven disks to create a volume, six disks are used for data, and one is used for parity; the volume capacity is 432 GB. Assuming that a 72-GB disk results in 67.9 GB of physical capacity, six 72-GB disks provide 407.4 GB of storage capacity. The actual amount of physical storage capacity might vary, depending on the disk manufacturer.

You calculate the size of the volume by determining the type and the amount of data that will be stored in the LUNs on the volume. For more information, see Guidelines for calculating the size of a volume.

Optional information to create a volume

In addition to the number of disks, you can specify the size of the RAID group. For information about disk allocation or RAID groups and how to configure them, see the Data ONTAP 6.5 System Administration Storage Management Guide. For information about disk configurations for your filer model, see the System Configuration Guide.

Guidelines to use when creating volumes

NetApp strongly recommends that you create volumes using the following guidelines:

Do not create any LUNs on /vol/vol0.
When you first set up and configure the filer, Data ONTAP creates a /vol/vol0 root volume. This root volume is used by Data ONTAP to administer the filer.
Create a volume large enough to accommodate the LUNs that will be stored on the volume, using the information at Guidelines for calculating the size of a volume. At a minimum, create volumes using seven disks.
Ensure that the snapshot functionality is modified as follows:
- Set snap reserve to 0%.
- Turn off the automatic snapshot schedule.
Ensure that no other files or directories exist in a volume that contains a LUN.
If this is not possible and you are storing LUNs and files in the same volume, use a separate qtree to contain the LUNs.
If multiple hosts share the same volume, create a qtree on the volume to store all LUNs for the same host.
Ensure that the volume option create_ucode is enabled.
Data ONTAP requires that the path of a volume or qtree containing a LUN is in the Unicode format. This option is On by default when you create a volume, but it is important to verify that any existing volumes still have this option enabled before creating LUNs in them.

Setting the percentage of snap reserve space using the command line

To use the command line to set a percentage of snap reserve space on a volume and to verify what percentage is set, complete the following steps.

Step	Action
1	To set the percentage, enter the following command: snap reserve volname percent Note For volumes that contain LUNs and no snapshots, NetApp recommends that you set the percentage to zero. Example `snap reserve vol1 0`
2	To verify what percentage is set, enter the following command: *snap reserve [volname]* Example `snap reserve vol1` Result The following output is a sample of what is displayed: Volume vol1: current snapshot reserve is 0% or 0 k-bytes.

Step

Action

To set the percentage, enter the following command:

snap reserve volname percent

Note
For volumes that contain LUNs and no snapshots, NetApp recommends that you set the percentage to zero.

Example

snap reserve vol1 0

To verify what percentage is set, enter the following command:

snap reserve [volname]

Example

snap reserve vol1

Result

The following output is a sample of what is displayed:

Volume vol1: current snapshot reserve is 0% or 0 k-bytes.

Setting the percentage of snap reserve space using FilerView

To use FilerView to set a percentage of snap reserve space (or snapshot reserve space, as it appears in FilerView) on a volume and to verify what percentage is set, complete the following steps.

Step	Action
1	Launch FilerView, as described in Launching FilerView.
2	Click Volumes > Snapshots > Configure.
3	Select the volume you want to configure.
4	At the Snapshot Reserve field, enter 0 as the percentage of space the volume reserves for snapshots. Note For volumes that contain LUNs and no snapshots, NetApp recommends that you set the percentage to zero.
5	Click the Apply button.

Turning off the automatic snapshot schedule using the command line

To turn off the automatic snapshot schedule on a volume and to verify that the schedule is off using the command line, complete the following steps.

Step	Action
1	To turn off the automatic snapshot schedule, enter the following command: *snap sched volname* 0 0 0** Example `snap sched vol1 0 0 0` Result This effectively turns off the snapshot schedule because no times are specified for snapshots to be taken automatically. You can still take snapshots manually using the `snap` command.
2	To verify that the automatic snapshot schedule is off, enter the following command: *snap sched [volname]* Example `snap sched vol1` Result The following output is a sample of what is displayed: Volume vol1: 0 0 0

Step

Action

To turn off the automatic snapshot schedule, enter the following command:

snap sched volname 0 0 0

Example

snap sched vol1 0 0 0

Result

This effectively turns off the snapshot schedule because no times are specified for snapshots to be taken automatically. You can still take snapshots manually using the snap command.

To verify that the automatic snapshot schedule is off, enter the following command:

snap sched [volname]

Example

snap sched vol1

Result

The following output is a sample of what is displayed:

Volume vol1: 0 0 0

Turning off the automatic snapshot schedule using FilerView

To turn off the automatic snapshot schedule on a volume and to verify that the schedule is off using FilerView, complete the following steps.

Step	Action
1	Launch FilerView, as described in Launching FilerView.
2	Click Volumes > Snapshots > Configure.
3	Select the volume you want to configure.
4	At the Hourly Snapshot Schedule, ensure that no time slots are selected. For example, if a check appears at 8:00 AM, click it to deselect it.
5	Click the Apply button.

Verifying and modifying the volume option create_ucode using the command line

To use the command line to verify that the Create Unicode Format Directories By Default volume option is enabled, or to enable the option, complete the following steps.

Step	Action
1	To verify that the `create_ucode` option is enabled (On), enter the following command: *`vol status [`volname`] -v`* Example `vol status /vol1 -v` Result The following output is a sample of what is displayed: Volume State Status Options vol1 online normal nosnap=off, nosnapdir=off, minra=off, no_atime_update=off, raidsize=8, nvfail=off, snapmirrored=off, resyncsnaptime=60,create_ucode=on convert_ucode=off, maxdirsize=10240, fs_size_fixed=off, create_reserved=on raid_type=RAID4 Plex /vol/vol1/plex0: online, normal, active RAID group /vol/vol1/plex0/rg0: normal Note If you do not specify a volume, status on all volumes is displayed.
2	To enable the `create_ucode` option, enter the following command: *vol options volname* create_ucode on** Example `vol options vol1 create_ucode on`

Step

Action

To verify that the create_ucode option is enabled (On), enter the following command:

vol status [volname] -v

Example

vol status /vol1 -v

Result

The following output is a sample of what is displayed:

Volume  State   Status  Options

  vol1  online  normal  nosnap=off, nosnapdir=off,

                        minra=off, no_atime_update=off,

                          raidsize=8, nvfail=off, 
                        snapmirrored=off,

                        resyncsnaptime=60,create_ucode=on

                        convert_ucode=off,

                        maxdirsize=10240,

                        fs_size_fixed=off,

                        create_reserved=on

                        raid_type=RAID4 

 

       Plex /vol/vol1/plex0: online, normal, active

          RAID group /vol/vol1/plex0/rg0: normal

Note
If you do not specify a volume, status on all volumes is displayed.

To enable the create_ucode option, enter the following command:

vol options volname create_ucode on

Example

vol options vol1 create_ucode on

Verifying and modifying the volume option create_ucode using FilerView

To use FilerView to verify that the Create Unicode Format Directories By Default volume option to is enabled, or to enable the option, complete the following steps.

Step	Action
1	Launch FilerView, as described in Launching FilerView.
2	Click Volumes from the left panel.
3	Click Manage.
4	Locate the name of the volume you want to check, and click the Modify icon for that volume.
5	Locate the Create New Directories in Unicode field and select On if it is Off.
6	Click the Apply button.