SnapLock storage solution

What is SnapLock?

SnapLock is an advanced storage solution that provides an alternative to traditional optical WORM (write-once-read-many) storage systems for non-rewritable data. SnapLock is licensed, open-protocol functionality that works with application software to administer nonrewritable storage of reference data.

How SnapLock works

WORM data resides on SnapLock storage volumes that are administered much like regular storage volumes. SnapLock volumes operate in WORM mode and support standard file system semantics. Data on a SnapLock volume can be created and committed to WORM state by transitioning the data from a writable state to a read-only state.

Marking a currently writable file as read-only or marking a directory as read-only on a SnapLock volume commits the data as WORM. This commit process prevents the file from being altered or deleted by applications, users, or administrators.

Data that is committed to WORM state on a SnapLock volume is immutable and cannot be deleted. The only exceptions are empty directories and files that are not committed to a WORM state. Additionally, once directories are created, they cannot be renamed.

Licensing SnapLock functionality

SnapLock volumes can be licensed as SnapLock Compliance or SnapLock Enterprise. These two licenses are mutually exclusive and cannot be enabled at the same time.

SnapLock Compliance
A SnapLock Compliance volume is recommended for strictly regulated environments. This license enables basic functionality and restricts administrative access to files.
SnapLock Enterprise
A SnapLock Enterprise volume is recommended for less regulated environments. This license enables general functionality, and allows you to store and administer secure data.

You can add or remove the license for SnapLock functionality by using the license command. To add the license, enter

sys1> license add <code>

The following message is displayed:

A snaplock site license has been installed. Snaplock enabled.

To remove the license, enter

sys1> license delete snaplock

The following message is displayed:

Unlicensed snaplock. Snaplock disabled.

Creating a SnapLock volume

A SnapLock volume is created in the same way a standard filer volume is created. To create a SnapLock volume, you must have at least two new or data-free disks: a SnapLock volume and a parity disk to store data reconstruction information.

To specify a volume as SnapLock, use the -L parameter with the vol create command. For example:

vol create vol-name -L [-r raid-group-size] [-l language_code] 
 disk-list

vol-name is the name of the new volume (without the /vol/ prefix).

-L designates the volume as SnapLock. The -L option does not take an argument. Confirmation is required when you are creating a SnapLock volume.

raid-group-size is the RAID group size you specify. The default RAID group size is eight disks.

language_code specifies a language other than that of the root volume. The default is the language of the root volume.

disk-list is one of the following:

ndisks[@disk-size]
ndisks is the number of disks to use. The number must be at least 2.

disk-size is the disk size to use, in gigabytes. You must have at least ndisks 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. Use a space to separate multiple disks.

Volume status

You can use the vol status command to verify that the volume exists. The vol status command output displays the attribute of the SnapLock volume in the Options column. For example:

sys1> vol status

Volume State	Status	Options
vol0 online	normal	root
vol_name online	normal	snaplock

Autosupport

The filer sends Autosupport messages to Network Appliance Technical Support. These messages include event and log-level descriptions. SnapLock volume state and options are included in Autosupport output.

Replicating SnapLock volumes

You can replicate SnapLock volumes to another filer using the SnapMirror feature of Data ONTAP. If an original volume becomes disabled, SnapMirror ensures quick restoration of data. See the SnapMirror chapter in the Data Protection, Online Backup and Recovery Guide for more information.