By Henry Baltazar  |  Posted 2004-12-13 Print this article Print

Network Appliance Inc.s Data OnTap 7G operating system widens the reach of the companys storage virtualization and management capabilities. The operating system, released last month, allows NetApp systems to manage heterogeneous storage and lets IT managers leverage NetApp virtualization and data protection technologies without replacing storage systems or undertaking expensive fork-lift upgrades.

All new NetApp systems will ship with Data OnTap 7G, and older appliances can be upgraded to it (company customers with maintenance contracts can upgrade for free). eWEEK Labs tested the operating system on a number of appliance systems at NetApps testing lab in Sunnyvale, Calif.

The storage virtualization space is crowded with vendors, including DataCore Software Corp., Softek Storage Solutions Corp., StoreAge Networking Technologies Ltd. and FalconStor Software Inc. However, NetApps mature NAS (network-attached storage) technologies should give it a leg up.

Data OnTap 7G has several features that will help IT managers enhance the use and availability of storage systems. For example, the virtualization capabilities effectively spread data across several disks, improving storage performance by using many spindles.

The operating systems FlexVol capability lets IT managers pool large storage units and allocate consolidated storage resources on demand.

Data OnTap 7G introduces a data container known as an aggregate.

In previous versions of Data OnTap, volumes were tied to physical storage entities, whether a single RAID set or a group of RAID sets. This was an inflexible scenario that made resource sharing difficult.

Aggregates combine all the physical storage resources managed by a NetApp appliance into a single virtualized storage pool, regardless of the types of storage in the pool.

Because a single aggregate can support several FlexVols, all the volumes on the aggregate can share the spindles in the storage pool to boost performance.

During tests, we found it easy to set up and manage FlexVol volumes. After creating the volumes, we could easily carve them into smaller pieces and allocate them to test servers.

Data OnTap 7G can increase and decrease volume sizes as needed, an important capability that IT managers can use to increase storage use. These resizing capabilities work well on file shares, but the resizing of LUNs (logical unit numbers) depends on the operating system and file system of the servers.

NetApps thin-provisioning functionality, new in the operating system and similar to the Capacity on Demand feature in Softek Storage Manager, gives IT managers the ability to create virtual storage. Using thin provisioning, IT managers can assign virtual storage space to a client and repurpose unused space.

For example, if a client asks for a terabyte of storage but uses only 500GB of it— a frustratingly common scenario—thin provisioning will allow the unused storage space to be claimed and assigned to another client. Should the original client need more storage, Data OnTap 7G can quickly and seamlessly add the storage on demand, without IT intervention.

The new FlexClone feature allows IT managers to create instantaneous file system replicas without storage overhead. During tests, we could mount the primary storage volume on a production server while mounting a clone of that volume on a test server.

Both servers could read from and write to the same volume without affecting each other. To accomplish this, Data OnTap 7G tracks changes in both volumes (the master and the clone). Using this feature, IT managers will be able to test new service patches and upgrades without disrupting production servers.

NetApps FlexClone is similar in function to the MultiView option from StoreAge.

Click here to read Labs review of StoreAge SVM 4.3. Although Data OnTap 7G does a good job of consolidating and managing storage, there is room for improvement. In the current version, heterogeneous disk pooling (pooling storage from different vendors) is not supported. As a result, an IT manager with, for example, both Hitachi Data Systems Corp. and EMC Corp. storage systems would have to use different appliances to manage them.

NetApp officials said heterogeneous disk pooling is planned for a future release of Data OnTap 7G.

In addition, the operating system does not allow clustering beyond two-node active-active failover. This should be adequate for most consolidation chores, but NetApp will need to support multinode clustering in the future to support larger clusters.

Senior Analyst Henry Baltazar can be reached at henry_baltazar@ziffdavis.com.

Check out eWEEK.coms for the latest news, reviews and analysis on enterprise and small business storage hardware and software.


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