Zero is Thin Provisioning’s New Calling Card

No one likes to be thought of as a “zero” but that is exactly how 3PAR wants the industry to perceive the newest management features on its InServ storage systems. The adoption and integration of thin provisioning into 3PAR’s storage systems already give it a competitive edge. But today’s announcement of its new Thin Engine, a “zero” out algorithm that facilitates  the adoption and preservation of thinly provisioned volumes in new and existing deployments may prompt even more companies to zero in on the savings that 3PAR’s systems can deliver.

EMC, IBM, HP, Hitachi, and Dell are often touted as the primary enterprise storage vendors with up to 70% or more of the storage market depending on whose numbers you believe while others such as 3PAR make up about 2% of the total storage market. But that tide could be changing as noted in a recent article which states, “a comparison with EMC and other enterprise storage array competition implies that 3PAR is gaining market share.”

So what’s the reason for this? The article goes on to state, “The company’s (3PAR’s) virtualized InServ arrays compete for enterprise storage business with EMC Symmetrix, HDS USP, HP EVA and XP, and IBM’s DS8000 and XIV products. InServ products stand out for their early and strong focus on thin-provisioning and their popularity with service providers.”

It seems that more companies in this tough economic environment are realizing the benefits of using thin provisioning and the ability for a storage array to provision capacity on a pay-as-needed basis. It improves capacity utilization, simplifies storage administration costs and lowers cost of ownerships while cutting the huge up front costs associated with traditional monolithic storage systems.

The rub for many companies is that if they are just starting out with thin provisioning, that is not so difficult. Data centers can simply introduce 3PAR into their environments for new applications, allocate some thinly provisioned volumes to these applications and away they go only consuming capacity as new writes are done on the volumes. The more data centers can just slap in some thinly provisioned volumes and off they go–consuming capacity as new writes are done on the volumes. The difficult part is getting off of the fat volumes that they are already using and migrating to thin volumes so they can take advantage of thin provisioning, which can often be the majority of their deployed capacity. The challenge has been that a storage technology refresh requires a terabyte-for-terabyte replacement of capacity.    

Since many companies have not had this luxury of starting off thin, 3PAR has, in today’s announcement, released four new products that will make it easier for companies to adopt thin provisioning even if they are already using fat volumes and then stay thin. The significance of these new products means that a technology refresh of a 200TB installation might only require 50TB of new capacity. That’s an impressive savings in an area, tech refresh, that has typically been left out of capacity reduction efforts. Also as part of the announcement, 3PAR is providing new industry direction for companies to help them build thin ecosystems within their environments.

  • Getting Thin. The goal of getting thin (not to be confused with simply starting out thin) requires converting fat volumes to thin volumes. Moving existing volumes to 3PAR’s thin volumes requires block-level migrations but until now the problem with this approach is that every block on the source volume is copied whether or not it contains data. A tech refresh was precisely a terabyte-for-terabyte project. 

This then leaves3parThinProvisioning thumb new volumes on 3PAR systems over provisioned even after the migration is complete.The announcement of today’s 3PAR Thin Conversion product changes this. 3PAR leverages industry standard block migration technology but now performs an inline zero detection using its Gen2 ASIC and virtualizes unused space from the fat volume with its Thin Engine as volumes are copied to a 3PAR array. This analysis, done at wire speeds, maps free space and only lays down written data on disk.  The end result is a tech refresh that occupies far less capacity, costs a lot less, uses less power, and takes up less space.

The fat to thin migration using 3PAR’s Thin Conversion is a simple 2-step process. A quick check of the file systems and related volumes give you a quick sense of the capacity savings. Zeros are then written within the file system to any unused space which lets the 3PAR ASIC detect what blocks are used and unused. Then as data is ingested by the 3PAR InServ system, it will only map and lay down blocks that contain actual data. 3PAR has found this method works as fast as the migration occurs, usually just minutes for most volumes.

  • Staying Thin. Keeping volumes thin over time can be as difficult as getting them thin in the first place. What can occur in environments with thin unfriendly file systems is that applications write out new data and then quickly delete it. The writes consume the available capacity but when data is deleted, the file system may not efficiently reuse  the freed blocks and are “stuck” in the thin volume. This is also seen in applications that have lots of transient data that is written and then quickly deleted, or in the deletion of very old snapshots.

To address this, 3PAR’s new Thin Persistence and Thin Copy Reclamation features use the Thin Engine to reclaim these freed blocks when data is deleted. Thin Persistence is ideal for keeping your VMware VMs thin by running utilities like Windows SDelete or the equivalent inside your VMs on a regular or utilization-trigged basis.  It can also keep your VMware datastores thin by using VMfktools to zero out the VMDKs of VMs you are about to delete. The Thin Engine in Thin Persistence reclaims the capacity automatically as these tools are run.  It can also be used periodically like Thin Conversion where zeros are written across deleted space in the file system which in turn, frees the associated capacity.

Thin Persistence can be turned on and off on a volume by volume and can be scheduled to run whenever – weekly, monthly, quarterly, or immediately after other scheduled tasks take place which in turn triggers the ASIC in the 3PAR system to de-allocate the underlying capacity.

Thin Copy Reclamation is similar to Thin Persistence but is used on copy volumes. Because 3PAR maintains the copy space mapping, as data is deleted, the Thin Engine immediately knows about the deletion and can actually un-map the capacity as it occurs. This means, when a snapshot that’s been around too long for example and has grown in size, the capacity can be immediately freed from thin copies and used elsewhere.

  • Demand Thin. About a year ago, 3PAR announced a partnership with Symantec to jointly develop a thin API to leverage standard SCSI commands that would allow a host file system to inform 3PAR at a volume level which blocks were freed when files were deleted. This approach, which relies on a standard SCSI command called WRITE-SAME, is mirrored in the T
    10
    SCSI standard for thin provisioning.

To encourage the “thin data center,” 3PAR is actively prodding its file system partners to take advantage of this new thin provisioning API. It should be no surprise that the very first product built on this emerging standard is Thin Reclamation for Veritas Storage Foundation, given 3PAR’s work with Symantec on the API. This product will leverage the API for communication between the VxFS file system and the Thin Engine within the 3PAR array so that as files are deleted on 3PAR thin volumes, Storage Foundation will inventory the block list and then push that block list to the 3PAR array which it will then use to free up that capacity.

In this economic environment everyone is looking for new ways to add value without sacrificing the features they need. Today’s Thin Conversion, Thin Copy Reclamation, Thin Persistence, and Thin Reclamation announcements from 3PAR do so in a most innovative and simple way. By providing a utility that zeros out blocks that no longer contain data, not only does it contribute to saving money and easily recovering unused storage on thinly provisioned volumes, it gives companies a whole new way to look at the value of zero.

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