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Top Nine Storage Concepts Every Virtualization Administrator Should Understand

Dell Software points out nine storage concepts today's virtualization administrators should understand if they are going to manage the virtual environment effectively.

Storage configuration is a foundational element of a modern data center environment, yet storage remains a complex challenge for many organizations. Without storage, the virtual environment cannot operate, since there would be no place for the machines to exist. At the same time, the storage configuration can make or break infrastructure performance and availability, so it's important that configuration be right for the virtual environment.

As organizations continue to leverage innovative technologies to modernize the data center, the roles of IT administration are beginning to converge, with responsibilities expanding into new domains. Yesterday's 'silo' administrator is quickly becoming today's 'infrastructure administrator,' a next-generation role requiring a broad spectrum of knowledge across multiple IT domains. As part server administrator, virtual environment manager, network engineer, and storage architect, today's infrastructure administrator needs the skills to build, maintain and manage high performing data center infrastructure solutions. It's the administrator's job to create a flexible infrastructure in which capacity can be scaled up or down as business requirements change, while concentrating simultaneously on data center cost optimization.

As a leading provider of storage tools for the enterprise, Dell Software has identified nine storage concepts an infrastructure administrator needs to understand to holistically manage the virtual environment.

Top Nine Storage Concepts for Virtual Environments:

1. What are VAAI and ODX and why are they so popular and important?

Both VMware vStorage APIs for Array Integration (VAAI) and Microsoft Offloaded Data Transfer (ODX) have features that allow organizations to maximize their storage investments, although VAAI is considered slightly more mature. Both VAAI and ODX aim to place more responsibility for handling overall storage operations on the storage infrastructure, without constantly having to involve the host. As virtualization-specific technologies that can introduce significant storage-related performance gains in the data center, VMware VAAI and Microsoft ODX are becoming increasingly common, and are powerful constructs that can improve storage operation performance by orders of magnitude.

2. What are the best ways to measure various aspects of the storage environment?

Storage capacity is often considered the most important metric for measuring the storage environment. But, while ensuring the environment has enough physical storage capacity to meet workload requirements is important, it's equally important to track metrics related to performance. When storage performance becomes problematic, the workloads running on that storage can behave erratically, causing a negative effect on the business. Performance statistics that should be tracked regularly include latency - the time it takes for an entire storage operation to take place - and IOPS, the number of Input/Output Operations per Second (IOPS) that can take place.

3. How do different kinds of hard drives differ from one another?

The type of storage deployed into the data center directly affects both the overall potential availability of applications, and the organization's ability to acquire sufficient storage to meet capacity needs. Three of the options available when it comes to choosing hard drives for a server or storage array are:

  • Serial ATA (SATA) disks, the capacity workhorses of the IT industry. They are available in capacities of up to 4 TB, but are at the bottom of the food chain when it comes to performance and overall reliability.
  • Near Line SAS (NL-SAS) disks, in which the actual disk platters are enterprise grade SATA platters, and the connector is of the SAS variety. This combination allows customers to enjoy SATA's capacity benefits while also enjoying some advanced features afforded by the SAS connector.
  • Serial Attached SCSI (SAS) disks, a staple in the data center when it comes to enterprise level storage. Compared to SATA and NL-SAS disks, SAS disks are both faster and an order of magnitude more reliable, but they lack the capacity of SATA units.

4. What is solid-state storage and why is it important?

Solid state is the fourth hard drive option for a server or storage array. Expensive solid-state storage has been available for quite some time. Solid-state disks are less expensive today, but remain the most expensive type of storage when it comes to capacity. They are much more affordable when performance is the primary metric. Because they have no moving parts, solid-state disks sport low latency and very good random access performance. They are reliable, require less power than rotating disks, and experience no physical wear and tear or mechanical breakdowns, but they are smaller than hard disks, and are only good for a finite number of erase/rewrite cycles before they are effectively dead.

5. What different RAID levels are available and what is the impact of each?

RAID can stand for Redundant Array of Inexpensive Disks, or Redundant Array of Independent Disks, depending on the source. Either way, RAID, although an aging technology, continues to play a vital role in the data center. Available RAID levels include levels 0, 1, 5, 6, 10, and 50. With the exception of RAID 0, the purpose of each level is to protect your data from hardware failure. RAID 0, which sometimes is used to boost overall storage performance, affords no data protection. For virtualization administrators who must rely on RAID technology for underlying storage, the choice of RAID level carries long-term ramifications, so it's important to thoroughly understand the pros and cons of each.

6. How do enterprise level storage features play important roles in virtualization?

Enterprise-class storage features can have a significant impact on how the environment operates, and require careful consideration. Three of these features include:

  • Thin provisioning, which allows administrators to overprovision virtual server storage capacity without actually wasting any storage space. Downsides include physical disk space constraints and a potential performance penalty.
  • Deduplication, which provides significant benefits to organizations that want to maximize the return on investment for their storage environments. The deduplication engine attempts to match patterns in blocks and files with existing data. When a match is found, the deduplication engine simply writes a pointer to the original copy of the data instead of creating a duplicate, so storage capacity need is reduced
  • Encryption, which is critically important to security of the virtual environment. Some storage arrays protect the data while it's at rest, which means theft of the array, or of an individual drive, can't leave the organization at risk. Good encryption techniques keep companies from falling victim to preventable storage compromises.

7. What is Microsoft's contribution to the storage arena? Microsoft added many new features to the operating system of Windows Server 2012 that are designed to help organizations reduce their storage spend. They include:

  • Storage space - aggregates all available and supported storage into a single pool or storage. This feature can help organizations that can't afford a traditional SAN gain access to centrally managed storage at a much lower cost.
  • TRIM/UNMAP - Windows Server 2012 implements an UNMAP capability that allows the thin provisioning process to reclaim previously used space that has since become unused.
  • Deduplication - added to the operating system in Windows Server 2012. It's a post-process deduplication method that works on a file basis by breaking files down into small chunks and running these chunks through the deduplication engine.
  • iSCSI Target Software, also built into the operating system of Windows Server 2012, includes storage spaces support, 4K sector disk support and Server Message Block (SMB) 3.

8. What storage transport mechanisms are available? The storage transport is one of the most challenging decisions for a virtualization administrator, and the storage choice will directly impact how the virtual machines are created. Choices include:

  • Direct Attached Storage, directly attached to servers and possibly consisting of hard drives plugged directly into slots in the server, or an external storage device connecting to the server with SAS cables, for example. Direct attached storage is useful for a small environment.
  • Network attached Storage (NAS), generally file-based devices that operate using SMB or NFS over TCP/IP networks. NAS devices are typically standalone appliances that reside on the network and, in most cases, can be used to store virtual machines.
  • Storage Area Networks (SANs), used in data centers for a long time to provide robust, highly available shared storage environments. The three primary types of SANs include iSCSI, Fiber Channel, and Fiber Channel over Ethernet (FCoE)

9. What different kinds of storage arrays are on today's market? There is a type of storage out there for just about every need. Balancing understanding of the different types of storage arrays with the organization's specific needs will help administrators make the right choice. Storage arrays on the market today include:

  • Hard disk-based arrays, excellent for capacity, poor for performance
  • Hybrid storage arrays, very good for both capacity and performance
  • All Flash storage arrays, poor for capacity, excellent for performance
  • Server-side flash, poor for capacity, excellent for performance

Leveraging a Triple-A approach for smooth, effective storage infrastructure management:

Once the concepts of storage configuration and optimization have been mastered, the next step is to keep the storage infrastructure running smoothly so that it fully supports both virtual and physical data center infrastructure. A Triple-A approach - incorporating predictive analytics, actionable advice, and intelligent automation - will lead to a flexible infrastructure in which capacity can be scaled up or down as business requirements change, while simultaneously focusing on data center cost optimization.

Learn more about Foglight for Virtualization solutions, and how a Triple-A approach will help a virtualization administrator to become a true cross-domain infrastructure administrator.

'As the virtualization manager's role edges more and more toward managing the infrastructure as a whole, it's crucial for that individual to have broad knowledge of all aspects of the infrastructure. The virtualization environment requires storage to operate, and the infrastructure's performance and availability are closely tied to the storage configuration, as well. We offer these nine storage concepts to help the infrastructure manager gain the knowledge necessary to keep the storage infrastructure running smoothly, so that it fully supports both the physical and virtual data center infrastructure.' -- John McNelly, Product Marketing Manager, Dell Software

Check out this whitepaper:

'Top Nine Storage Concepts Every Virtualization Administrator Should Understand,' Dell Software white paper:
Published Tuesday, July 30, 2013 6:59 AM by David Marshall
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