Data Ontap 7G abolishes preallocation tyranny

Network Appliance has brought out the latest version of its Data Ontap software, which imposes a grid storage architecture on...

Network Appliance has brought out the latest version of its Data Ontap software, which imposes a grid storage architecture on NetApp devices by creating an abstraction layer between application servers, storage controllers and disc arrays.

Chris Bennett, NetApp's director of marketing, said Data Ontap 7G used a single global name space to give storage administrators a single view of storage resources and pooled processing power across the company's network-attached storage arrays.

A new FlexVol tool allows volumes or identifiable units of storage to be spread across disc spindles in a logical manner for greater resiliency and higher performance.

It also lets storage administrators set policies around storage provisioning so volumes can grow on the fly according to how much space business applications need. For example, a volume can present itself to an application server as 10Tbytes in size, but only contain 1Tbyte until the application calls for the additional capacity.

Mike Forman, IT director at Cadence Design Systems, said the flexible volumes would allow him to create more accurate charge-back models for his users. “You can assign a 500Gbyte logical unit number to a user and if he’s only using 50Gbyte you can take the other 450Gbyte and give it to someone else and the user never knows about it. We’ve been asking for this for years."

According to Bennett, utilisation rates are far higher because storage is not preallocated. Performance can almost double because the data is shared across disc array trays, allowing more than one engine to process I/O commands.

Bennett also said policies could be set to alert administrators when disk capacity usage reached specified thresholds, allowing them to add more physical storage.

Enterprise Strategy Group analyst Tony Asaro said NetApp’s “thin provisioning” software was unique in the sense that no other leading storage supplier currently offers it. “To me, it's one of the most useful things. This is one of the top things I recommend to storage vendors to support."

Release 7G of Data Ontap also includes the new FlexClone tool, which performs snapshots or point-in-time replication of data sets for test, development and simulation scenarios. Bennett said the snapshots, which require no disc space, could be manipulated and tested without affecting the initial data set.

He also said that the company's network-attached storage engine, the gFiler, could now serve up block-level data through a Fibre Channel or ISCSI protocol. ISCSI allows block-level data transfers to occur over ubiquitous Ethernet.

The latest version of the gFiler engine can also use arrays from Hewlett-Packard as its back-end storage as well as arrays from IBM and Hitachi.

FlexVol is bundled free with Data Ontap. FlexClone is separately licensed from around $6,000 (£3,238).

Lucas Mearian writes for Computerworld

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