Condusiv Technologies Blog

Condusiv Technologies Blog

Blogging @Condusiv

The Condusiv blog shares insight into the issues surrounding system and application performance—and how I/O optimization software is breaking new ground in solving those issues.

VMware Advises on Defrag

by Brian Morin 27. July 2016 01:40

VMware: Defrag or Not?

Dave Lewis sent in a question, “There is such a quandary about disk fragmentation in the VMware environment. One says defrag and another says never. Who's right? This has been a hard subject to track and define.”

I’m going to debunk “defragging” in a minute, but if you read VMware’s own best practice guide on improving performance (found here), page 17 reveals “adding more memory” as the top recommendation while the second most important recommendation is to “defrag all guest machines.”

As much as VMware is aware that fragmentation impacts performance, the real question is how relevant is the task of defragging in today’s environment with sophisticated storage services and new mediums like flash that should never be defragged? First of all, no storage administrator would defrag an entire “live” disk volume without the tedious task of taking it offline due to the impact that change block activity has against services like replication and thin provisioning, which means the problem goes ignored on HDD-based storage systems. Second, organizations who utilize flash can do nothing about the write amplification issues from fragmentation or the resulting slow write performance from a surplus of small, fractured writes.

The beauty behind V-locity® I/O reduction software in a virtual environment is that fragmentation is never an issue because V-locity optimizes the I/O stream at the point of origin to ensure Windows executes writes in the most optimum manner possible. This means large, contiguous, sequential writes to the backend storage for every write and subsequent read. This boosts the performance of both HDD and SSD systems. As much as flash performs well with random reads, it chokes badly on random writes. A typical SSD might spec random reads at 300,000 IOPS but drop to 23,000 IOPS when it comes to writes due to erase cycles and housekeeping that goes into every write. This is why some organizations continue to use spindles for write heavy apps that are sequential in nature.

When most people think of fragmentation, they think in terms of it being a physical layer issue on a mechanical disk. However, in an enterprise environment, Windows is extracted from the physical layer. The real problem is an IOPS inflation issue where the relationship between I/O and data breaks down and there ends up being a surplus of small, tiny I/O that chews up performance no matter what storage media is used on the backend. Instead of utilizing a single I/O to process a 64K file, Windows will break that down into smaller and smaller chunks….with each chunk requiring its own I/O operation to process.

This is bad enough if one virtual server is being taxed by Windows write inefficiencies and sending down twice as many I/O requests as it should to process any given workload…now amplify that same problem happening across all the VMs on the same host and there ends up being a tsunami of unnecessary I/O overwhelming the host and underlying storage subsystem.

As much as virtualization has been great for server efficiency, the one downside is how it adds complexity to the data path. This means I/O characteristics from Windows that are much smaller, more fractured, and more random than they need to be. As a result, performance suffers “death by a thousand cuts” from all this small, tiny I/O that gets subsequently randomized at the hypervisor.

So instead of taking VMware’s recommendation to “defrag,” take our recommendation to never worry about the issue again and put an end to all the small, split I/Os that are hurting performance the most.

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Defrag | Diskeeper | General | virtualization | V-Locity

The Student Enrollment Blues

by Scott Thomas 21. January 2014 06:58

It was a bad day for Steve Bettoni, Tech Support and IT Procurement Officer of Stockport College. Steve is responsible for the infrastructure that supports the college's enrollment apps, SAP, and Exchange, so you can imagine his level of anxiety on enrollment day—the busiest day for any education institution—when the system crashed and the finance director got involved.

Steve's team had already spent hours, days, and weeks troubleshooting helpdesk calls related to poor application performance. The team virtualized to get more from legacy systems, but with the increase in I/O traffic, application response time began to suffer.

Steve heard about Condusiv’s V-locity acceleration software and its ability to solve the toughest application performance challenges without adding new hardware. A bit skeptical, he decided to evaluate the solution—and dropped enrollment processing times from 15 minutes down to 5. Convinced of what V-locity could do for their applications, he deployed on other VMs and saw a 522% improvement with SAP and 85% improvement with Exchange.

Read the full story: Stockport College case study.

NEW V-locity 4 VM Accelerator Improves VM Performance by up to 50%

by Jeff Medina 10. December 2012 10:00

Today we are very excited to announce the release of V-locity 4 VM Accelerator. With this latest release, V-locity increases VM and application performance by up to 50% and does so without any additional storage hardware.

Let’s face it - in today’s world of virtual environments, we generate a tremendous amount of data and it’s only the beginning. In fact, findings included in a recent study by IDC titled “Extracting Value from Chaos” predict that in the next ten years we will create 50 times more information and 75 times more files.

The impact of this data explosion on server virtualization can often lead to I/O bottlenecks. This is because a physical server running multiple virtual machines (VMs) must often carry out far more I/O operations than one server running a single workload, and typical virtualization environments emulate I/O devices that run less efficiently than native I/O devices.

In essence, virtualization acts like a funnel, combining and mixing many disparate I/O streams, sending out to the disk what becomes a very random I/O pattern. To make matters worse, the more VMs are added, the more the issue is compounded as more I/O is "randomized." All of this has a very negative affect on storage performance, and renders time-honored techniques such as read-ahead buffers and caching algorithms far less effective than in conventional physical environments.

Storage I/O is the most critical issue in a virtualized environment, and can cause organizations to spend a great deal on storage, purchasing more and more disk spindles, but often using only a fraction of their capacity because of performance issues. The outcome is that, due to issues relating to performance bottlenecks in the storage infrastructure, some applications are deemed unable to be virtualized; however, a properly tuned storage environment might have accommodated those applications. So what’s the alternative? The answer is V-locity 4 VM Accelerator. 

V-locity 4 VM Accelerator provides:

  • Increased application performance up to 50%
  • Up to 50% faster access to frequently accessed files
  • Faster I/O performance without the cost of additional storage hardware
  • Increased VM density per physical server up to 50%
  • Extended hardware lifespan by eliminating unnecessary I/Os
  • Automatic and real-time operation for true “Set It and Forget It®” management 

What makes V-locity 4 so effective is its powerful toolkit of proactive technologies, including IntelliWrite,® V-Aware,® CogniSAN,® InvisiTasking® and the new IntelliMemory® RAM caching technology.

New! IntelliMemory™ Caching Technology
IntelliMemory intelligent caching technology boosts active data, improving I/O response time up to 50% or more while also eliminating unnecessary I/O operations from getting into the network or storage.

Improved! IntelliWrite® Technology
IntelliWrite automatically prevents the operating system from breaking files into pieces and writing those pieces in a performance penalized manner. This proactive approach improves performance up to 50% or more while preventing any negative impact to snapshots replication, data deduplication or thin provisioning growth. As this proactive approach happens at the server level, the network and shared storage simply has less I/O operations to transfer and process.

New! Performance Benefit Analyzer
The Performance Benefits Analyzer helps document the performance benefits of V-locity. The benefit analyzer looks at your current system performance, then compares these results to those after using V-locity to provide a detailed report showing specific improvements and benefits to your system.

V-Aware® Technology
V-Aware detects external resource usage from other virtual machines on the virtual platform and eliminates resource contention that might slow performance.

CogniSAN® Technology
CogniSAN detects external resource usage within a shared storage system, such as a SAN, and allows for transparent optimization by not competing for resources utilized by other VMs over the same storage infrastructure. And it does this without intruding in any way into SAN-layer operations.

InvisiTasking® Technology
InvisiTaksing allows all the V-locity 4 "background" operations within the VM to run with zero resource impact on current production.

Set It and Forget It®
Automatic and real-time operation.

For more details and a FREE trial, visit www.condusiv.com/products/v-locity or call a sales representative at 1-800-829-6468.

Space Reclamation, Above and Below

by Damian 7. November 2011 09:29

Thin provisioning is a fairly hot topic in the storage arena, and with good reason. Many zones within the business and enterprise see massive benefit from the scalability of thin provisioning, and it can be a cost saver besides. However, the principle of thin provisioning suffers some unique maladies at both client and storage levels.

Some storage arrays include a feature permitting thin provisioning for their LUNs. This storage layer thin provisioning occurs below the virtual platform storage stack, and essentially means scalable datastores. Horizontal scaling of data stores adds a new tier of agility to the storage ecosystem that some businesses absolutely require.

LUN thin provisioning shouldn’t be confused with Virtual Disk TP, which works at a file level (not array). Thin provisioned VMs can expand based on pre-determined use cases, adding an extra degree of flexibility to storage density. Intelligently combining TP at multiple tiers yields some pretty neat capacity results.

Datastore thin provisioning has been the source of some concern for storage administrators with regards to recovery from over-provisioning. When virtual disks are deleted or copied away from a datastore, the array itself is not led to understand that those storage blocks are now free. You can see how this can lead to needless storage consumption.

vSphere 5 from VMware introduced a solution for this issue. The new vSphere Storage APIs for Array Integration (VAAI) for TP uses the SCSI UNMAP command to tell the storage array that space previously occupied by a VM can be reclaimed. This addresses one aspect of the issue with thin VM growth.

Files are not simply being written to a virtual disk, they’re also deleted with regularity. Unfortunately, there is no associated feature within virtual platforms or Windows to inform the storage array that blocks can be recovered from a thin disk which should have contracted after deletions. Similar to the issue above, this leads to unnecessary storage waste.

With the release of V-locity 3 in 2011, we introduced a new Automatic Space Reclamation engine. This engine automatically zeroes out “dead” free space within thin virtual disks, without requiring that they be taken offline and with no impact on resource usage. So what does this mean? Thin VMs can be compacted, actually reclaiming the deleted space to the storage array for dynamic use elsewhere. The thin virtual disks themselves are kept slimmed down within datastores, giving more control back to the storage admins governing provisioning.

Space Reclamation with V-locity

You can read more about VAAI for TP in vSphere 5 on the VMware blog here.

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virtualization | VMware | Windows 7

The Summer Blockbuster Sequel: V-locity 3.0

by Michael 24. June 2011 07:00

Coming Soon: V-locity 3.0 (virtual platform optimizer)  has some fantastic new features in it we're sure you’ll like, including:

+Full Support for ESXi Server (in addition to existing support for ESX and Hyper-V)

+Reduced installation effort for ESX Servers (no installation on Host)

+New CogniSAN technology (for storage area networks)

+New V-Aware technology (for any virtualization platform)

+Automatic zeroing of free space (for thin/dynamic virtual disks)

+Added support for virtualization platforms such as XenServer, RHEV, Oracle VM and more

We are just a few short weeks from releasing it, and could use your help. If your interested in catching a “sneak peak” (our final release candidate build), and are interested and able to install, evaluate and then comment (fill out a 10 minute online survey) on this software, simply fill-out a Non-Disclosure Agreement (NDA) located here.

Fax the signed NDA to:
Fax: 818-252-5514

Please add the following to the Fax cover page:
Attn: Field Test Administrator/V-locity Field Test

Alternatively you can email the signed NDA (scan in the pages with your signature) to our Field Test administrator. Please add "V-locity Field Test" in the subject line.

UPDATE July 28, 2011:

Congrats to Benjie Henderson, Virtualization Architect at SS&C, winner of the iPad2 raffle held for release candidate testers! 

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Hyper-V | SAN | virtualization | V-Locity | VMware

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