NetApp makes a step toward grid

NetApp makes a step toward grid

Sometimes I wish I had a penny for every megabyte of enterprise storage that is not used or is a redundant copy.

If a storage genie granted my wish, I would quickly be rich because in many datacenters a significant amount of storage space is wasted. Usually, that's because volumes are unnecessarily large or because running parallel business processes demands multiple simultaneous and space-hogging copies.

Don't blame storage administrators for that waste: They do the best they can with the limited management tools that vendors provide. For those using Network Appliance gear, however, an unexpected and empowering Christmas present is coming.

Let's quickly recap why it's so common to waste storage. Part of the problem is that estimating the size of, say, a new database with any degree of accuracy is really difficult.

That translates to assigning the new database more space than is needed -- often twice as much or more -- rather than risk crashing an application because its database is out of space.

Obviously, it's better to waste some storage -- it's cheap, after all -- than risk disrupting business activities. After all, when the new database has been running for a while, its real storage demands become clear, and we can adjust its volume size accordingly, right?

Not quite. Most storage systems don't allow you to shrink a volume on the fly, so to recoup that wasted space, an admin would have to first create a smaller volume and then move over all the data from the original copy.

This is an easy process but one that quite possibly requires stopping the applications that use that volume. If you're still wondering why nobody cares to shrink a volume, go back two paragraphs and read that first sentence aloud again.

Back to Network Appliance: In November, the company announced Data ONTAP 7G, a new version of its flagship OS that promises dramatically improved storage provisioning tools.

In essence, 7G opens Data ONTAP to storage virtualization by proposing two technologies, FlexVol and FlexClone. The first is capable of creating virtual, hardware-independent volumes, whereas the second expedites the creation of volume copies and dramatically reduces the amount of duplicated data.

To understand how FlexVol works, imagine being able to create a volume 500GB in size without actually using any of that space until some data is copied to that virtual image. In essence, even if you overprovision a volume, there is no wasted space because what counts are the gigabytes you actually fill with data, not what you allocate.

FlexVol also makes the provisioning faster because Data ONTAP keeps an accurate inventory of the space available on physical storage, freeing the administrator from managing that activity, which translates into more accurate bookkeeping of storage resources.

Paradoxically, you can squeeze better performance from your hardware with FlexVol because virtual volumes can span multiple physical disks and arrays, spreading applications' I/Os over more spindles and controllers.

And finally, FlexVol can use every fragment of free space on your storage arrays, maximizing storage utilization to levels that human-driven provisioning could never reach.

FlexVol's sibling, FlexClone, is the logical complement to better storage administration because it extends the benefits of FlexVol to snapshots. FlexClone doesn't actually duplicate all data but will create a virtual clone with pointers at the original data so that you can make a copy of that 500GB volume in seconds.

You can modify the clone, which will use some actual disk space for the changed data only: FlexClone maintains a single copy of all data available to both the original volume and clone that has not changed. Considering that making multiple copies of the same data is quite common, FlexClone should cut the space occupied by clones significantly.

Unfortunately, FlexClone is not free: You will have to pay an additional license fee. But if you are a NetApp customer, FlexVol won't cost you anything because it comes with Data ONTAP 7G, which is a free update.

Although the FlexVol and FlexClone news is probably enough for anybody to digest, NetApp had a parallel announcement concerning gFiler, NetApp's Trojan horse into other vendors' SANs. In essence, the gFiler appliance opens those foreign devices to NetApp's powerful file sharing system and to its rich portfolio of storage management applications.

This separate announcement is essentially a quiet reminder that if you have gFiler, the benefits of 7G are also available on other vendors' hardware. Plus, NetApp expanded gFiler support to more arrays, including models from Hewlett-Packard and IBM, to its original lineup of Hitachi Data Systems and Sun Microsystems devices.

That takes care of the latest news from NetApp. But I am now reconsidering attempts to find that storage genie. If FlexVol becomes popular, my chances of getting rich on the penny plan will become very slim. FlexClone takes away even more of my possible riches.

Oh well, there goes my chance of making Bill Gates green with envy.

Mario Apicella is a senior analyst at the InfoWorld Test Center.

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