Reduction of computational effort by using representative

This table lists the equivalent feature nomenclature for the operations and tasks

evaluated in this white paper. The list covers the two vendors with a brief description of the core functionality and descriptions for each vendor’s implementation of that

functionality. The cell will be blank if the vendor lacks an equivalent feature.

IBM Storwize V7000 EMC VNX5500 Description Physical Storage

Physical storage is used to configure and manage storage pools, internal and external storage, and MDisks, and to migrate existing storage to the system.

Internal Storage Internal storage is the RAID-protected storage that is directly attached to the Storwize V7000 system.

Storage Pool A storage pool is a collection of MDisks that jointly contain all of the data for a specified set of volumes.

Storage Pool

A storage pool is a means of storage allocation from any type of disk and can incorporate multiple tiers (Flash, FC, and SATA) in the same pool. Storage pools are defined by an administrator before the creation of any LUNs.

LUNs can be created at pool level; these pool LUNs are no longer bound to a single storage tier and can be spread to different storage tiers within the same pool.

Some or all of disks in a system, collected into a unit of or for virtual space. (The characteristics of such collections vary with vendor).

MDisks

A managed disk (MDisk) is a logical unit of

physical storage. MDisks are either arrays (RAID) from internal storage, or volumes from external storage systems. MDisks are not visible to host systems.

RAID Groups

A RAID group is a type of storage pool. It is a set of disks with a RAID type on which you create one or more LUNs with the same RAID type. The LUN is distributed equally across all the disks in the RAID group.

RAID group is the actual container for data

protection, where multiple LUNS or volumes are created and assigned to a host.

IBM Storwize V7000 EMC VNX5500 Description Volume

A volume is a logical disk that the system presents to the hosts. MDisks in a pool are split into

"extents" of the same size.

Volumes are created from the extents that are

available in the pool.

There are three types of volumes: striped, sequential, and image.

Application servers on the SAN access volumes, not MDisks or drives. To keep a volume accessible even when an MDisk on which it depends has become unavailable, a mirrored copy can be added to a selected volume. Each volume can have a maximum of two copies. Each volume copy is created from a set of extents in a storage pool.

LUN

A logical unit number (LUN) is a unique

identifier used to designate individual or collections of disk devices for address by a protocol associated with a SCSI, iSCSI, Fibre Channel (FC), or similar interface.

LUN or volume is a logical disk created from a storage pool and assigned to host. A LUN could reference an entire RAID set, a single hard disk, or multiple disks.

IBM Storwize V7000 EMC VNX5500 Description thin-provisioned volume has a virtual capacity plus a real capacity.

Virtual capacity is the volume storage capacity that is available to a host.

Real capacity is the storage capacity that is allocated to a volume copy from a storage pool.

In a fully allocated volume, the virtual capacity and real capacity are the same. In a thin-provisioned volume, however, the virtual capacity can be much larger than the real capacity.

Thin LUN

A pool LUN with a thin property. A thin LUN is able to have a subscribed user capacity that is greater than the user capacity of the shared pool.

Virtual provisioning/thin provisioning is a strategy for efficiently managing space in a storage area network (SAN) by allocating physical storage on an "as needed"

basis.

This strategy gives a host, application, or file system the illusion that it has more storage than is physically provided.

Physical storage is allocated only when the data is written, rather than when the application is initially configured.

IBM Storwize V7000 EMC VNX5500 Description FlashCopy

FlashCopy software lets you make an instant, point-in-time copy from a source volume to a target volume. Without it, if the data set changes during the copy operation, the resulting copy might contain data that is not consistent. More advanced FlashCopy functions allow operations to occur on multiple source and target volumes.

FlashCopy management operations are

coordinated to provide a common, single point-in-time for copying target volumes from their respective source volumes. This creates a consistent copy of data that spans multiple volumes. The FlashCopy function also allows multiple target volumes to be copied from each source volume. This can be used to create images from different points in time for each source.

Rollback/Restore Snapshot or Clones

If the rollback is performed while a snapshot is still active to this session, the snapshot writes will be copied to the source LUN.

If the snapshot is

deactivated, the original session data will be copied to the source LUN. of data protection, used in creating an instant, point-in-time copy of the source volumes or LUNS.

It is difficult to make a consistent copy of a data set that is constantly updated; point-in-time copy techniques help solve this problem.

IBM Storwize V7000 EMC VNX5500 Description Snapshot

The snapshot preset creates a point-in-time view of the production data. A snapshot is not intended to be an

independent copy, but is used to maintain a view of the production data at the time that the snapshot is created. Therefore, the snapshot holds only the data from regions of the production volume that have changed since the snapshot was created.

Clone

The clone preset creates an exact replica of the

volume, which can be changed without impacting the original volume. After the copy operation completes, the mapping that was created by the preset is

automatically deleted.

Backup

The backup preset creates a point-in-time replica of the production data. After the copy operation

completes, the backup view can be refreshed from production data with minimal copying of data from the production volume to backup volume.

SnapView Snapshot The defined virtual device that is presented to a host and enables visibility into running sessions. The snapshot will be defined under a source LUN in such a way that activation of that snapshot will only be allowed on any running sessions belonging to that same source LUN. A snapshot can only be assigned to a single session; thus, to have two active snapshots for the same source LUN, you must have two separate sessions running in which to activate two separate snapshots. Active snapshots are fully read and write-capable. Once the snapshot is

deactivated, however, all writes to the snapshot will be deleted.

SnapView Clone

Snap View clones are fully populated point-in-time copies of LUNs that allow incremental

synchronization between source and destination LUNs.

IBM Storwize V7000 EMC VNX5500 Description Reserved LUN Pool

Collection of LUNs used to support the pointer-based design of SnapView. As the first SnapView session is started on a given source LUN, a reserved LUN is assigned to the source LUN. If a SnapView session runs long enough for the assigned reserved LUN to be filled, the next available LUN in the reserved LUN pool will be assigned to the source LUN. Reserved LUNs are thus assigned on a per-source-LUN basis, such that source LUNs have a one-to-many relationship to their reserved LUNs.

Server writes made to an activated snapshot are also stored on a reserved LUN in the global reserved LUN pool. When you deactivate the snapshot, the reserved LUN space is freed and all snapshot writes are

destroyed.

IBM Storwize V7000 EMC VNX5500 Description FlashCopy Mappings

A FlashCopy mapping defines the relationship between a source volume and a target volume.

The FlashCopy feature makes an instant copy of a volume at the time that it is started. To create an instant copy of a volume, one must first create a mapping between the source volume (the disk that is copied) and the target volume (the disk that receives the copy).

The source and target volumes must be of equal size.

SnapView Session This is the process of defining the point-in-time designation by invoking copy-on-first-write activity for updates to the source LUN. Starting a session assigns a reserved LUN to the source LUN if no other sessions are running on this same source LUN.

Note that as far as this session is concerned, until a snapshot is activated, the point-in-time copy is not visible to any servers.

However, we are tracking the source LUN so we can, at any time in the future, activate a snapshot to this session in order to present the point-in-time image (when the SnapView session was started) to a host. As noted earlier, each source LUN can have up to eight sessions.

IBM Storwize V7000 EMC VNX5500 Description FlashCopy Consistency

Groups

A consistency group is a container for mappings.

Many mappings can be added to a consistency group. Enabling a single, consistent point-in-time copy across multiple volumes, consistency groups are important in scenarios, such as a database environment,

The consistency group is specified when the mapping is created. The consistency group can also be changed later.

When using a consistency group, prepare and start that group instead of the individual mappings.

This process ensures that a consistent copy is made of all the source volumes.

Mappings to control at an individual level are known as stand-alone mappings.

Storage Group

A storage group is a logical grouping of hosts and LUNS. The Storage Group option lets you place LUNs and hosts into a group so that the designated LUNs are accessible only to the particular hosts included in the storage group.

IBM Storwize V7000 EMC VNX5500 Description Remote Replication

The Metro Mirror and Global Mirror Copy Services features enable IT administrators to set up a relationship between two volumes, so that updates that are made by an application to one volume are mirrored on the other volume. The volumes can be in the same system (usually only for testing purposes) or on two different systems (usually at different physical locations).

RecoverPoint is a single solution that provides host-based and array-based solutions while replicating data from any SAN-based array to any other SAN-based array over existing Fibre Channel or IP network. It provides the ability to go back in time and recover data in a consistent state. It provides support for heterogeneous storage, hosts, networks, and SANs.