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Understanding MultiStore

What MultiStore is  Top

MultiStore is an optional software product that enables you to partition the storage and network resources of a single storage system so that it appears as multiple storage systems on the network. Each "storage system" created as a result of the partitioning is called a vFilerTM unit. A vFiler unit, using the resources assigned, delivers file services to its clients as a storage system does.

The storage resource assigned to a vFiler unit can be one or more qtrees or volumes. The network resource assigned can be one or more base IP addresses or IP aliases associated with network interfaces. You can add or remove resources at any time.

Licensing MultiStore  Top

Because MultiStore is an optional software product, you must enable the software license for it. The name of the license is MultiStore.

Reasons for using MultiStore  Top

MultiStore is typically used for the following reasons:

MultiStore for server consolidation

The following scenarios illustrate how you can use MultiStore to consolidate servers:

MultiStore for service providers and enterprises

Service providers, such as Internet service providers (ISPs) and storage service providers (SSPs), can partition the resources of a storage system to create many vFiler units for client companies. Similarly, the information technology (IT) department of an enterprise can create vFiler units for various organizations, or customers, within the enterprise.

The administrator for each customer can manage and view files only on the assigned vFiler unit, not on other vFiler units that reside on the same storage system. In addition, there is no data flow between vFiler units. A customer using a vFiler unit can be assured that no sensitive information is exposed to other customers that store data on the same storage system.

For example, an SSP can create the following vFiler units on a storage system:

Although both CompanyA and CompanyB store data on the same storage system, network traffic for each company is restricted to the specified interface. The administrator at CompanyA, which uses NFS to access data, cannot use the showmount command on a UNIX client to view directories on the storage system that are outside the /vol/vol1 volume. Similarly, the administrator at CompanyB, which uses CIFS to access data, cannot browse the shares that are outside the /vol/vol2 volume.

See Chapter 3, Using vFiler Units in Different IPspaces for a more detailed discussion.

MultiStore for data migration

MultiStore enables you to migrate data from one storage system to another without extensive reconfiguration on the destination storage system.

Without MultiStore, you can use the SnapMirror technology to copy data from one storage system to another, but you then need to edit the files' access control lists (ACLs), local user group definitions, user mapping information, and so on, before users can access the data. If the data being copied is stored on a vFiler unit, however, all user, group, and ACL information is encapsulated in the vFiler unit. You re-create a vFiler unit on the destination storage system with the encapsulated information, and data can be served from the destination storage system without further reconfiguration. UNIX clients do not experience any disruption in service when the vFiler unit on the destination storage system starts serving data instead of the vFiler unit on the source storage system.

About the hosting storage system  Top

The storage system on which you create vFiler units is called the hosting storage system. The storage and network resources used by the vFiler units exist on the hosting storage system.

About the default vFiler unit  Top

When you license MultiStore, Data ONTAP automatically creates a default vFiler unit on the hosting storage system. The name of the default vFiler unit is vFiler0.

Initially, vFiler0 owns all the resources on the storage system. After you create additional vFiler units, vFiler0 owns the resources that are not owned by the vFiler units you create.

The default vFiler unit exists as long as the MultiStore license is enabled. On a storage system with the MultiStore license enabled, you cannot destroy vFiler0.

All information provided in this guide about the vFiler units is applicable to vFiler0, unless noted otherwise.

Some limitations of MultiStore  Top

MultiStore has the following limitations:

You can create 32 vFiler units on a storage system. The 33rd vFiler unit is vFiler0, which is created automatically when MultiStore is licensed on the storage system. vFiler0 continues to exist as long as MultiStore is licensed on the storage system.

In a cluster, you can create up to 32 vFiler units on each node of the cluster.

For more information about the vFiler unit limit, see Adjusting the vFiler unit limit.

  • Only Ethernet interfaces are supported for vFiler units.
  • Only the NFS, CIFS, Internet SCSI (iSCSI), HTTP, and FTP protocols are supported for the vFiler units.
  • Not all Data ONTAP commands are supported on the vFiler units.

    Hosting storage system's access to data contained in a vFiler unit  Top

    As the hosting storage system administrator, you do not have administrative, CIFS, or NFS access to the data owned by the vFiler units (other than data owned by the default vFiler unit, vFiler0). After you assign a qtree or volume to a vFiler unit, you lose access to the data in that qtree or volume.

    Example

    Before you create a vFiler unit with the /vol/vol1 volume, you can configure the /etc/exports file so that you can mount the /vol/vol1 volume. After you create the vFiler unit, an attempt to mount the /vol/vol1 volume from the hosting storage system results in the error message ".../vol/vol1 belongs to vFiler unit A, can't mount from vol0."

    To regain administrative control of storage owned by a vFiler unit, see Administering vFiler unit resources from the hosting storage system.

    Sample vFiler unit  Top

    A storage system named "toaster" has the MultiStore license enabled and is configured with three volumes, which are /vol/vol0, /vol/vol1, and /vol/vol2.

    Because the MultiStore license is enabled, a default vFiler unit, vFiler0, is created on toaster.

    On toaster, you can create a vFiler unit named vFiler1. You can assign the IP address 123.123.123.1, the qtree /vol/vol0/qtree1, and the volume /vol/vol1 to vFiler1. Traffic destined for vFiler1 uses the IP address 123.123.123.1, and all data served by vFiler1 is stored in the assigned qtree and volume.

    If /vol/vol0/qtree1 is the first path specified for vFiler1 on the vfiler create command line, this qtree becomes vFiler1's primary storage, containing the vFiler's /etc directory.

    The storage system named toaster is the hosting storage system for vFiler1. vFiler0 uses all the IP addresses created on toaster except 123.123.123.1 and the following resources for storage:

    For information about accessing a vFiler unit's file system using CIFS and NFS, see Accessing a vFiler unit's file system with CIFS and NFS.

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