What is Hybrid Storage, and How Does It Compare to Traditional VAAI?

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1 Server Virtualization and Industry Leading Hybrid Storage: Better Together Version 1.0: February 2013 Contents Introduction... 1 VAAI for better efficiency and better cost... 2 VM-aware for better insight... 5 Hybrid for better performance and capacity... 6 Deduplication with no compromises for better capacity, flexibility and cost... 7 No comprises connectivity for better integration... 8 Summary... 9

2 Introduction It s reality: The de facto standard platform for new server-based workloads is no longer a physical hardware device, but is now a software-led instance of a hardware device commonly referred to as a virtual machine (VM). In other words, organizations are taking a virtual first approach with regard to the deployment of new server workloads and relying on traditional single-application physical servers only when there is a specific reason to do so. As a result of this new reality, and as hypervisor capabilities continue to increase, organizations are pushing the capabilities of their virtual environments like never before. Bigger workloads that just a few years ago would have defaulted to physical infrastructures are now being deployed on monster-sized virtual machines. Mission-critical applications that used to demand their own isolated compute and storage resources are now being pushed into the ever-expanding virtual environment and living with both the pros and the cons of this non-physical environment. In traditional server consolidation virtualization projects, it was not uncommon to see host server RAM become exhausted long before other resources, such as processing power. However, as these new and more substantial workloads find their way into the hypervisor managed environment, another critical resource one that didn t used to garner much attention among mainstream companies has become a second resource challenge: disk performance as measured in IOPS. Fortunately for organizations everywhere, there is a readily available solution to this growing resource challenge. Hybrid storage arrays have taken the storage marketplace by storm and are the solution when it comes to the most mundane all the way to the most complex server virtualization needs. There are four key features that make the right hybrid storage array the best choice for your server virtualization solution. Storage: Better Together Revision 1.0 February

3 VAAI for better efficiency and better cost With the release of vsphere 4.1, VMware more fully recognized the growing need to more deeply link the hypervisor with expensive storage arrays. As customers began to push the hypervisor to even greater levels than in the past, it became clear that the status quo would be a major hindrance for growing virtual environments. How did this happen? As organizations moved more and more workloads away from their physical confines to the virtualization layer, a multitude of new management opportunities began to appear. For example, consider something as simple as cloning a virtual machine. In a software-led world, such an operation is commonplace, particularly because the hypervisor layer makes it possible to create easily accessible virtual machine templates. In considering what goes into a clone, it s really just a large file copy. But that seemingly simple cloning operation, when performed in a traditional environment, is actually quite complex and resource intensive. Here s an overview of the process. 1. The vsphere host contacts the storage array and begins locating the contents that are to be cloned. 2. On a block-by-block basis, that content is transferred over the storage communications network to the vsphere host, where it undergoes some processing. 3. The vsphere host then writes each block back to the storage array. The storage communications fabric plays an integral role in this process as blocks make their way up the fabric to the vsphere server and back down the fabric to a second storage location. It s entirely possible that such an operation, performed at the wrong time, could have a detrimental impact on the overall performance of the virtual environment. For example, suppose this operation took place during a retailer s holiday season and managed to disrupt customer order entry. Such an even could be catastrophic from a financial perspective. That s where VMware vsphere Storage APIs Array Integration (VAAI) comes in. VAAI, which is sometimes is referred to as "hardware offloading," is a set of API primitives that allow the hypervisor to more directly control certain storage functionality, which can minimize the chances of a significant impact on the fabric during clone, Storage vmotion and other significant data move and copy operations. In the previous scenario, the clone operation could be completely offloaded to an array that supports the appropriate VAAI primitives. When this happens, the vsphere host provides Storage: Better Together Revision 1.0 February

4 the array with enough pertinent information and the entire clone happens within the confines of the array. However, VAAI doesn t stop there. There are a number of additional VAAI capabilities that came with vsphere 4.1 and, with the release of vsphere 5, VMware added a number of additional API primitives for storage vendors. A complete list of the various primitives provided by VAAI is found in the table below. Name Purpose Block NFS vsphere 4.1 vsphere 5 Atomic Test & Set (ATS) / Hardware Locking Cloning Blocks / Full Copy, Extended Copy Zeroing File Blocks / Block Zeroing / Write Same Out of Space / Thin Provisioning Stun* SCSI UNMAP / Dead Space Reclamation Quota Exceeded Behavior / TP Soft Threshold TP LUN Reporting / Report Thin Capacity NFS Full File Clone / Hardware Snap NFS Space Reservation / Zeroedthick Files NFS Extended Statistics / Extended Statistics NFS Space Reclaim / Space Reclamation NFS Fast File Clone / Linked Clone Offload Provides for granular locking of block storage devices, making operations more efficient -- Offloads a clone or copy operation directly to the array, away from the hypervisor Offloads the task of zeroing new blocks for expanding thinly provisioned storage -- Allows graceful handling of out of space provisions in the event thinly provisioned space runs out Allows reclamation of freed up space on thinly provisioned volumes -- Provides proactive alerts to help administrators avoid running out of volume space Tells vsphere the thin provisioning status for a volume Offloads a clone or copy operation directly to the array, away from the hypervisor Enables the creation of thick VMDK files, enabling reservation of all space needed by a VMDK -- Enables visibility into space usage on NAS data stores (thin provisioning) Allows reclamation of freed up space on thin provisioned volumes -- Enables the creation of virtual machine snapshots to be offloaded to the storage array - Fully Supported - Undocumented - Not Supported --- Not Applicable *The Out of Space / Thin Provisioning Stun primitive was partially introduced in vsphere 4.1, but was undocumented. Storage: Better Together Revision 1.0 February

5 As organizations look for new storage to support ongoing server virtualization needs, it s important to remember that VAAI support is not found in all storage systems. VAAI support is an optional service that storage vendors can choose to implement in their arrays in order to enable a number of direct benefits. With a solution that provides full VAAI support, there are tremendous direct and indirect benefits that can be had, including: achieving greater levels of virtual machine density on hosts since the hosts are relieved of processing responsibility for many move and copy operations. a storage communications fabric that is not subjected to peak demand on as frequently, thus enabling production workloads to continue operating without interruption or constraint. gaining proactive insight into disk capacity issues that could affect production, and therefore allow you to keep services available. the potential to deploy improved disaster recovery services without having to negatively impact vsphere host systems. These are all laudable goals. Organizations seeking to maximize their virtual environment in every possible way to achieve maximum return on investment would do well to ensure that the storage environment supports VAAI. For new arrays, determining VAAI support is generally an easy task the vendor can simply answer the question. However, since VAAI is a software construct, support can be added to firmware updates for existing storage arrays, too. As such, even if the array a company buys today doesn t support all of the VAAI primitives that are necessary, support for those missing primitives may be added in a future update. An organization should check with their storage vendor to see if support exists in their equipment. A hypervisor combined with VAAI-enabled storage = A better choice. The Tegile story As of this writing, Tegile supports all of the block- and NFS-level VAAI primitives supported by vsphere 5.1. Storage: Better Together Revision 1.0 February

6 VM-aware for better insight VAAI can help the hypervisor achieve higher levels of control over the storage layer, which can translate into a more productive and less expensive environment. But there s more to be gained when there is even tighter integration between the hypervisor layer and storage. In recent years, the concept of procuring storage that is aware of the virtualization layer has gained traction and has become, for many, an important consideration. Dubbed virtualization-aware or VM-aware storage, this new paradigm brings virtualization administrators benefits that help ensure the long-term health of the virtual environment and enable more timely resolution of performance-related issues that may arise in the environment. VM-aware storage brings to life the following possibilities: Once vsphere is connected to VM-aware storage, an administrator can quickly and easily correlate virtual machine and storage performance characteristics. Such correlation enables administrators to immediately identify vampire virtual machines that might be consuming more resources than expected and potentially be having a negative impact on other workloads. The figure shown below is an example of statistics that can be gathered from a Tegile array. With such insight, administrators can begin to gain an understanding about storage performance (read and write IOPS) on a per-virtual machine basis. Besides the aforementioned troubleshooting benefit, such information can be invaluable when it comes to workload planning efforts. In addition, understanding the impact that storage operations have on the storage fabric is critical to understanding whether the fabric is suitable for existing workloads. As such, with VM-aware storage, the storage is able to provide read and write throughput figures on a per-vm basis. Because every organization uses storage differently, the exact benefits from deduplication and compression may vary. With VM-aware storage, administrators can understand such details right down to the virtual machine level. The Tegile story Tegile s line of storage arrays come out of the box with VM-Aware management capabilities, making them a full partner in workload performance assessment and troubleshooting. Storage: Better Together Revision 1.0 February

7 Hybrid for better performance and capacity When one views the storage market, there are three classes of storage available for enterprises to purchase. The table below provides a quick overview of the various types of storage along with pros and cons for each type. As is quickly evident after a short study, it becomes obvious that hybrid delivers the most balanced capacity vs. performance opportunity for server virtualization projects. Moreover, for those organizations that find it necessary to add capacity to an existing hybrid array, Tegile s line of arrays can be easily Type Pros Cons Traditional Hard Disk Drives All Flash Storage Hybrid Storage Massive capacity at a low cost (low $/GB) Massive performance (very low $/IOPS) Balanced approach for both $/GB and $/IOPS Very low performance (very high $/IOPS) Low capacity at a high cost (high $/GB) None expanded with additional hard disk-based storage to meet the most demanding capacity needs. Certainly, traditional hard disk drives and allflash-based storage solutions have their place and serve an important purpose in niche needs. Traditional hard disk drive based storage remains the prime choice when capacity trumps all and when performance is not important. For example, this kind of storage remains important for archiving and backups needs. In these kinds of scenarios, the cost per gigabyte is the primary driver and high levels of performance are certainly not required. The downside is that it takes hundreds of disks to meet the performance capabilities of just one solid state disk. On the other side of the performance spectrum lies the all flash storage array. In these hardware devices, all storage is solid state and carries with it a very high cost per gigabyte. These devices, too, have their place in high end analytics and in other scenarios in which the cost per IOPS is vastly more important than the cost per gigabyte. The tradeoff, though, is that all-flash arrays are severely compromised when it comes to capacity. Enter the hybrid storage array. The emergence of the hybrid storage array has become the answer to many organizations storage woes. By leveraging expensive solid state disks in such a way as to accelerate traditional hard disk drives, hybrid storage arrays have brought a solution that perfectly balances the need for speed with the need for capacity. The Tegile story Tegile believes in no compromise customer choice. To this end, Tegile has an all-flash array with a hybrid twist in which users can deploy an all flash array from Tegile, but optionally add expansion shelves of spinning disk to resolve the capacity challenge of all-flash arrays. No compromise. Full flexibility. Storage: Better Together Revision 1.0 February

8 Deduplication with no compromises for better capacity, flexibility and cost Deduplication has become one of today s storage arrays' most popular and necessary features, particularly as flash-based storage has grown in customer acceptance. After all, that impressive solid state storage device carries with it an equally impressive price tag and not in a good way! Deduplication is a feature which takes data that may repeat many times on a storage device and stores it just once. So, if there are one thousand identical blocks on a storage device, only one of those blocks would be stored, and the remainder would be replaced with pointers to the single copy of the data in the deduplication table. Depending on the duplicity of the data, deduplication can have significant capacity benefits. As one considers the kinds of workloads that are found in the data center, it becomes clear that there is ample opportunity for deduplication to have a major impact. Hybrid storage already provides a relatively low cost per gigabyte, but with deduplication that spans both the solid state and the hard disk-based storage in the array, that cost per gigabyte figure can plummet very quickly while, at the same time, the cost per IOPS remains steady. Not all hybrid solutions are created equal, though. For organizations considering hybrid storage, it s critical to ensure that the solution s deduplication feature actually covers both the flash and the hard disk-based storage. There are hybrid solutions on the market where deduplication occurs only on solid state disks in the array and not the hard disks. This technique will yield only very minimal deduplication results since it operates only on the low capacity drives while ignoring the high capacity disks. If an organization is in the market for storage for their server virtualization storage system, then they should ensure that they choose a solution that takes a no-compromises approach to deduplication and that it deduplicates all disks, not just a few. Doing so yield additional return on investment in the form of increased usable capacity. Regardless of solution, deduplication of the solid state disks can actually result in a performance increase in the array. The reason being, as more data is able to be stored and cached on the solid state disks, more data is able to use that extremely high-speed storage. The Tegile story All of Tegile s arrays provide full solid state disk and hard disk deduplication with no compromise. In addition, Tegile s arrays allow administrators to disable deduplication on a volume by volume basis for workloads that do not benefit from the technology. Storage: Better Together Revision 1.0 February

9 No compromises connectivity for better integration It s true that there are many, many storage solutions on the market today, but many of them are shackled with unpleasant compromises that force organizations to have to make tradeoffs in order to implement the solution that they need. Does the solution your organization intends to purchase support your needs? Here are a few questions you should ask: Do you need Fiber Channel or do you need iscsi? Do you need NAS support or do you need an array that provides block level connectivity? Do you need NFS or do you need CIFS/SMB support? The answer to all of these questions should be, It doesn t matter. The selected storage solution should provide you with a no-compromises set of features that don't require the you to try to define in advance every single need that you may face for the life of the solution. By choosing a solution that doesn t force technology limited compromise, you can change technology course midstream perhaps change from Fiber Channel to iscsi without having to replace the storage array. In addition, a hybrid storage array that falls into the no compromise category enables a wider array of customers to choose the solution. When it comes to how the various connectivity methods integrate with the hypervisor layer, you will find that it doesn t matter that much. All modern hypervisors support the range of physical (Fiber Channel & iscsi) and virtual (NFS & CIFS/SMB) connectivity methods. The Tegile story All of Tegile s arrays support the full spectrum of connectivity solutions, including Fiber Channel, iscsi, NFS, and CIFS/SMB. Storage: Better Together Revision 1.0 February

10 Summary Server virtualization remains the primary use case for today s storage environments and, due to their high cost, organizations need to find ways to maximize the return on investment for these pieces of equipment. By investing in the right market-leading hybrid storage array, organizations can enjoy the better together benefits that accompany hybrid arrays when coupled with the vsphere hypervisor. For a true no-compromise storage solution that is the perfect companion for any server virtualization environment, consider Tegile s award-winning line of arrays. To learn more about Tegile Zebi storage solutions for server virtualization, please visit or call us at: Toll Free Follow us on Twitter: The words Tegile and Zebi are trademarks of Tegile Systems, Inc. All other marks belong to their respective owners. Tegile Systems, Inc Storage: Better Together Revision 1.0 February