Insider Reports Thin Provisioning Risks

By Mary Jander October 26, 2007, 2;30 PM

While thin provisioning offers a convenient way to add storage quickly, it's not suitable for environments where rapid and regular storage consumption is the rule, according to the latest report from Byte and Switch Insider, a subscription research service affiliated with this publication.

"Fooling users and applications into thinking they have more storage capacity available to them than they actually do can cause problems. If they fill the actual physical storage at once, disk and application errors will occur, leading to significant downtime," writes author Martin Courtney in "Thin Provisioning & SANs: A Cure for Server Sprawl?"

This is hardly the first time thin provisioning, the technique whereby applications consume storage only as they write blocks or groups of blocks to a particular volume, has been issued a warning label. Guest author Tim Arland of Forsythe Solutions Group makes a similar point in his latest column, where he discourages users of OLTP apps from deploying the technology. And judging by readers' responses to his suggestions, the risks of thin provisioning are a concern for potential users.

All thin provisioning products on the market today, according to this month's Insider report, offer the ability to set thresholds on the use of physical storage, so administrators can stay ahead of any actual storage shortfall. Some leading-edge products offer a variety of alerts via email, pager, and SMS to make sure the message gets through.Problems may occur if an entire virtual storage pool created by thin provisioning software or firmware is suddenly and unexpectedly filled (by somebody quickly copying a large amount of data to disk in one go). If that happens, the thresholds can be swamped before the storage manager is able to add more physical capacity.

In the future, products may reduce this risk by recognizing when applications or processes are consuming too much storage and throttling back their consumption to avoid disaster.

The risks of thin provisioning don't negate its benefits. According to the report, the technique is especially suited to coping with the "server sprawl" that results when virtual machines are created to handle processing demands on the fly.

Nonetheless, many storage managers remain wary of thin provisioning as it now exists. As time passes, the report states, enhancements that involve better automated responses to potential problems should help create more user confidence in the technique.

Companies covered in this report include: 3PAR Inc.; Cloverleaf Communications Inc.; Compellent Technologies Inc.; DataCore Software Corp.; EMC Corp. (NYSE: EMC); EqualLogic Inc.; Hewlett-Packard Co. (NYSE: HPQ); Hitachi Data Systems Corp. (NYSE: HIT); Sun Microsystems Inc. (Nasdaq: SUNW); Intransa Inc.; LeftHand Networks Inc.; Network Appliance Inc. (Nasdaq: JAVA); and Pillar Data Systems Inc.Get more details and/or purchase the report here.

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