Understanding data management

Creating volumes

About creating volumes

When you create a volume, you must provide the following information:

A name for the volume.
Data disks to include in the volume. You can specify these either by disk ID or by number of disks of a specified size.
Disks are formatted for either block or zoned checksum type. Spare disks are listed according to checksum types. Rules for using checksum types are in the next section, Checksum type usage.

You can accept the defaults for the following items or specify other values:

RAID group size. The default is 8 disks.
The language used for file names. The default is the language of the root volume.

Checksum type usage

A checksum type applies to an entire volume. A volume can have only one checksum type.

Checksum type for root volume on new filer

When you run the setup command on a new filer, the checksum type for the root volume is chosen for you.

Checksum type for new volumes

When you create a volume, the filer determines the checksum type of the volume.

If enough block checksum disks are available, the volume uses block checksums.
Otherwise, the volume uses zoned checksums.

To use block checksums when you create a new volume, you must have at least the same number of block checksum spare disks available as you specify in the vol create command.

No checksum type conversion

You cannot convert a disk from one checksum type to the other. You cannot convert a volume from one checksum type to another.

Checksum types for existing volumes

The following table shows the types of disks that you can add to an existing volume of each type.

Disk type	Block checksum volume	Zoned checksum volume
Block checksum	OK to add	OK to add
Zoned checksum	Do not add	OK to add

Volume naming conventions

You choose the volume names. The names must follow these naming conventions:

Begin with either a letter or an underscore (_)
Contain only letters, digits, and underscores
Contain no more than 255 characters

Creating a volume

To create a volume, complete the following steps.

Step	Action
1	At the system prompt, enter the following command: vol create vol-name [-r raid-group-size] [-l language_code] disk-list vol-name is the name for the new volume (without the /vol/ prefix). raid-group-size is the RAID group size you want. language_code specifies a language other than that of the root volume. See Language codes. disk-list is one of the following: ndisks[@disk-size] ndisks is the number of disks to use. It must be at least 2. disk-size is the disk size to use, in gigabytes. You must have at least ndisk available disks of the size you specify. `-d` disk_name1 disk_name2... disk_nameN disk_name1, disk_name2, and disk_nameN are disk IDs of one or more available disks; separate multiple disks with a space.
2	Enter the following command to verify that the volume exists as you specified: *vol status vol_name* -r** vol_name is the name of the volume whose existence you want to verify. Result: The system displays the RAID groups and disks of the specified volume on your filer.
3	If you have...	Then...
	An NFS-only filer	Go to Step 5.
	A CIFS-only or multiprotocol filer	Create shares that refer to the new volume to enable clients to access it, then go to Step 4.
4	If you have...	Then...
	A CIFS-only filer	You are done.
	A multiprotocol filer	Go to Step 5.
5	Update the system /etc/exports file with the new volume.
6	Run `exportfs`.
7	Add the appropriate mount point information to the /etc/fstab or /etc/vfstab file on clients that mount volumes from the filer.

Volume creation example

The following command creates a volume called newvol, with no more than eight disks in a RAID group, using the French character set, consisting of the disks with the disk IDs 8.1, 8.2, 8.3, and 8.4.

vol create newvol -r 8 -l fr -d 8.1 8.2 8.3 8.4.

Parameters to accept or change after volume creation

After you create a volume, you can accept the defaults for CIFS oplocks and security style settings or change the values. You should decide what to do as soon as possible after creating the volume. If you change the parameters after files are in the volume, they might become inaccessible to users because of conflicts between the old and new values. For example, UNIX files available under mixed security might not be available after you change to NTFS security.

CIFS oplocks setting

The CIFS oplocks setting determines whether the volume uses CIFS oplocks. The default is to use CIFS oplocks.

Security style

The security style determines whether the files in a volume use NTFS security, UNIX security, or both.

When you have a new filer, the default depends on what protocols you licensed, as shown in the following table.

Protocol licenses	Default volume security style
CIFS only	NTFS
NFS only	UNIX
CIFS and NFS	UNIX

When you upgrade to Data ONTAP 6.1 from Data ONTAP 5.0 or earlier, the default security style is multiprotocol.

When you change the configuration of a filer from one protocol to another, the default security style for new volumes changes as shown in the following table.

From	To	Default for new volumes	Note
NTFS	Multiprotocol	UNIX	The security styles of volumes are not changed.
Multiprotocol	NTFS	NTFS	The security style of all volumes is changed to NTFS.