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.

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! 

Tags: , , , , ,

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

Finding Latencies in your VM/SAN Infrastructure

by Michael 30. March 2011 11:10

Okay, so you've bought, installed, connected, configured, and then tuned/optimized your new storage virtualization solution, but somehow there are still latencies with apps (e.g. SQL).

You've run the Storage Area Network (SAN) vendor utilities that:

  • did not see any contention on the disks in the RAID group(s). 
  • noted that the average I/O to physical disks did not exceed a reasonable number of I/O's per second on each volume in the meta device.
  • checked the utilization of the port that the Host Bus Adaptor (HBA) is zoned to and did not see any performance issues.
  • noted the switch port that the HBA is connected to is not saturated or reporting any errors.

And basically surmised "at this time we do not see any issue on the array or with the SAN in reference to this server."

However....

When running PerfMon within Windows, it continues to uncover latencies in the 100ms+ range. What the hayel!

This is when it's important to consider what those SAN optimization and reporting tools are providing. SANs can optimize storage from HBA-to-spindle. Above the HBA other factors cause latencies outside the scope or control of the SAN, and ultimately it is the App/User Experience that needs to be addressed.

So, it's time to look further up the storage stack.

Here is a great chart (borrowed from VMware here):

The chart helps simplify that SAN and even VM based latency monitoring and storage optimization do not account for latencies that may exist in the Guest Operating System (GOS). They are only aware of, and able to optimize I/O from the point they receive the traffic to the physical storage.

Monitoring performance in Windows does not go away simply because you've left direct attached storage (DAS) and physical servers to go virtual. There are numerous causes for poor performance on the GOS side, from poorly written apps, to incorrect configurations, to bad partitioning strategies, file system fragmentation and more. Pretty much all the issues that could cause poor Windows I/O performance on physical servers with DAS, still exist.

It's important to continue to use GOS based solutions to determine application latency such as PerfMon, which can support counters for popular apps (like SQL).

To evaluate if file fragmentation is a potential cause, track these metrics with Perfmon. Fragmentation will show up in the logical disk statistics referred to in the document. You can also use a freeware solution from Diskeeper Corporation; called Disk Performance Analyzer for Networks (DPAN) to collect file fragmentation statistics from any Windows system (physical or virtual) on your LAN/WAN.  You can download DPAN here.

Sample DPAN Report:

Tags:

Defrag | SAN

Best Practices for Storage Area Network (SAN) Defragmentation

by Michael 29. March 2011 02:30

Overview:

As high performing storage solutions based on block protocols (e.g. iSCSI, FC), SANs excel at optimizing block access. SANs work at a storage layer underneath the operating systems file system; usually NTFS when discussing Microsoft Windows®. That dictates that a SAN is unaware of “file” fragmentation and unable to solve this issue.


Fig 1.0: Diagram of Disk I/O as it travels from Operating System to SAN LUN.

With file fragmentation causing the host operating system to generate additional unnecessary disk I/Os (more overhead on CPU and RAM) performance suffers. In most cases the randomness of I/O requests, due to fragmentation and concurrent data requests, the blocks that make up the file will be physically scattered in uneven stripes across a SAN LUN/aggregate. This causes even greater degradation in performance.


Fig 1.1: Sample Windows Performance Monitor Report from fragmented SAN-attached NTFS volume.

Fortunately there are simple solutions to NTFS file system fragmentation; fragmentation prevention and defragmentation. Both approaches solve file fragmentation at the source, the local disk file system.

IntelliWrite® “The only way to prevent fragmentation before it happens™”

IntelliWrite is an advanced file system driver that leverages and improves upon modern Windows’ file system “Best Fit” file write design in order to write a file in a non-fragmented state on the initial write. Intelligently writing contiguous files to the disk provides four principal benefits above and beyond defragmentation, including:

  • Prevents most fragmentation before it happens
  • Better file write performance
  • An energy friendly approach to improving performance, as defragmentation is not required for files handled by IntelliWrite
  • 100% compatibility with copy-on-write technologies used in advanced storage management solutions (e.g. snapshots)

While eliminating fragmentation improves performance. it is important to properly configure and account for advanced SAN features.

With the increasing popularity of SANs, we've included instructions in the Diskeeper installation to ensure users properly configure Diskeeper:

We suggest reading this full document before executing any of the recommended configurations. These instructions apply to V-locity (used on VMs as well).

Best Practices:

Highlights:

Implementing Diskeeper on a SAN is simple and straightforward. There are two principal concepts to ensuring proper configuration and optimal results:

  • Ensure IntelliWrite is enabled for all volumes.
  • Find a time to schedule Automatic Defragmentation (more details below)
Details:

If you are implementing any of the following SAN based technologies such as Thin Provisioning, Replication, Snapshots, Continuous Data Protection (CDP) or Deduplication, it is recommended to follow these guidelines.

Defragmentation can cause unwanted side effects when any of the above referenced technologies are employed. These side effects include:

With SAN replication:
Likelihood of additional data replication traffic.

With Snapshots/CDP:
Likelihood of additional storage requirements for data that defragmented/moved and snapshot-related performance lag.

With Thin Provisioning:
Likelihood of additional storage requirements for data that defragmented/moved.

With Deduplication:
Potential for additional deduplication overhead. Also note that deduplication can be used to remove duplicate blocks incorrectly allocated due to defragmentation. This process can therefore be used to reclaim over-provisioned space.

This is why it is important to enable the fragmentation prevention (IntelliWrite) and change the Automatic Defragmentation to occur during non-production periods to address the pre-existing fragmentation:

During Installation, disable Automatic Defragmentation;


Uncheck the “Enable Automatic Defragmentation” option during installation.

Upon installation ensure IntelliWrite is enabled on all volumes (default). IntelliWrite was specifically designed to be 100% compatible with all advanced SAN features, and should be enabled on all SAN LUNs. IntelliWrite configuration is enabled or disabled per volume, and can be used in conjunction with Automatic Defragmentation, or exclusively.


To ensure IntelliWrite is enabled, right click a volume(s) and select the feature.


Then confirm “Prevent Fragmentation on this volume” is selected, and click “OK” to complete.

Once installed, enable Automatic Defragmentation for any volumes that are not mapped to a SAN LUN. This may include the System Partition (e.g. C:\).


To enable Automatic Defragmentation, right click a volume(s) and select the feature.


Then check “Enable Automatic Defragmentation on the selected volumes” and click “OK” to complete.

If you are not using any advanced SAN features, it is recommended to enable Automatic Defragmentation for all days/times. However, note that pre-existing fragmentation will require significant effort from Diskeeper to clean up. This effort will generate disk I/O activity within the SAN.

Therefore, if existing fragmentation is significant, initially schedule Diskeeper to run during off-peak hours. As Diskeeper has robust scheduling capability, this is easily configured.


To enable Automatic Defragmentation during non-production periods, right click a volume(s) and select the feature.


Then check “Enable Automatic Defragmentation on the selected volumes”. Diskeeper is then scheduled by using your mouse to highlight over the 30 minute blocks in the interactive weekly calendar.

The above example disables defragmentation Monday through Friday. It also disables defragmentation Saturdays and Sundays except between 7pm until 3:30am the following morning. This would afford 17 hours of defragmentation availability per week. Immediately following these scheduled defragmentation periods is when SAN maintenance for advanced features should be addressed (e.g. thin reclamation, deduplication).

Should accommodating SAN maintenance be difficult (e.g. limited maintenance windows)using a weekly optimization process, very granular scheduling is also available with Diskeeper. Note, maintenance windows are not required in order to implement and benefit from IntelliWrite.


To schedule for specific non-reoccurring dates and times in the future, select the “Turn Automatic Defragmentation on or off based on specific dates” option. Click any multitude of dates and times using Shift-Select or Ctrl-Select. Once done, click OK to complete.

If you are implementing the above mentioned advanced technologies and your SAN provides hot block optimization / data tiering, it is also recommended to disable I-FAAST® (Intelligent File Access Acceleration Sequencing technology). I-FAAST sequences hot “files” (not blocks) in a Windows volume, after determining hardware performance characteristics. The sequencing process creates additional movement of data for those advanced SAN features, and is therefore generally recommended to disable when similar SAN solutions are in place.


To disable I-FAAST, right click a volume(s) and select the feature.

Note, I-FAAST requires Automatic Defragmentation be enabled. Also note that I-FAAST is disabled by default in Diskeeper 2011 in certain cases. Also note that I-FAAST generates additional disk I/Os and will therefore cause an increase in the aforementioned Automatic Defragmentation side effects.

Once pre-existing fragmentation has been removed, increase the periods in which Diskeeper actively optimizes the Windows file systems. With real-time defragmentation and InvisiTasking® technology, Diskeeper immediately cleans up fragmentation (that is not prevented by IntelliWrite). This minimal ongoing optimization generates only invisible, negligible I/O activity.

New features in Diskeeper 2011 to improve SAN performance:

Diskeeper 2011 introduces SAN specific solutions. These default solutions automate many of the configurations required for SAN-attached servers.

Diskeeper 2011’s new Instant Defrag™ technology dramatically minimizes I/O activity, and exponentially speeds up defragmentation. The Instant Defrag engine is provided fragmentation information, in real-time, by the IntelliWrite file system filter driver (those fragments that it does not prevent). Without the traditional need to run a time and resource intensive whole-volume fragmentation analysis, Instant Defrag can address the recently fragmented files as they occur. This dynamic approach prevents a buildup of fragmentation, which could incur additional I/O overhead to solve at a later date/time.

Diskeeper 2011’s new Efficiency Mode (default) maximizes performance, while minimizing disk I/O activity. By focusing on efficiency and performance and not on presenting a “pretty disk” visual display, Diskeeper 2011 minimizes negative side effects (e.g. reduce snapshot storage requirements or thin LUN growth, etc..) while maximizing performance benefits. It is a SAN-optimized defrag mode and our recommended solution for SAN-attached Windows volumes.

By default, Efficiency Mode also disables proprietary file placement features such as I-FAAST.

Also, by default, Diskeeper 2010/2011 moves data to lower NTFS clusters, and hence generally “forward” on SAN LUNs.

Best Practices Summary:
  • Ensure IntelliWrite is enabled for all volumes.
  • Automatic Defragmentation should be enabled at all times for all direct attached storage volumes.
  • Use Efficiency Mode of Diskeeper 2011.
  • Schedule Automatic Defragmentation on SAN LUNs, based on use of advanced SAN features.
  • Run SAN processes such as space reclamation and/or deduplication on recently defragmented LUNs using advanced SAN features.

Want this in PDF form. Get it here: Best Practices for using Diskeeper on Storage Area Networks.pdf (3.00 mb)

Tags: , , , , ,

Defrag | Diskeeper | SAN

Diskeeper Receives U.S. Army Certificate of Networthiness

by Colleen Toumayan 9. March 2011 04:10

Diskeeper Corporation, Innovators in Performance and Reliability Technologies, announced that its Diskeeper 2010 performance software has received the Certificate of Networthiness (CoN) from the U.S. Army Network Enterprise Technology Command. The Certificate of Networthiness signifies that Diskeeper performance software is configured to the current Army Golden Master baseline and complies with all U.S. Army and Department of Defense (DoD) standards for security, compatibility and sustainability. A CoN is required for all enterprise software products deployed in the Army Enterprise Infrastructure Network and used by the U.S. Army, all National Guard, Army Reserve and DoD organizations that use the Army Enterprise Infrastructure.

Tags:

Defrag | Diskeeper | SAN

Faster Backups/Archiving/Dedupe/DR success with Diskeeper and V-locity

by Colleen Toumayan 27. January 2011 03:29

"Spokane Regional Health District uses CommVault Simpana backup/archiving/disaster recovery software installed on a dedicated server with 37TB of SAS attached storage.

                                                                                       

We perform daily full and incremental backups of all our servers. The data backup is disk-to-disk-to-tape and is deduplicated as it is saved on the SAS storage. The deduplication process can create a very large number of file fragments, sometimes over 1,540,000 fragments on a 2TB disk array. With Diskeeper EnterpriseServer automatic defrag running the response time of the arrays is approaching 0.02 second delay due to fragmentation. This has reduced our backup time by approximately 25 percent for any D2D2T job. 

SRHD also uses Microsoft Hyper-V and currently has 31 virtualized servers running on an Intel Modular Server. There are 72TB of storage available to the Modular Server via SAS connections featuring dual path IO. All of the data on the SAS arrays is maintained in RAID 60 logical disk drives. Since setting up V-locity, which has built-in support for VHD (virtual hard disks), with automatic defragmentation, our VHDs very seldom show any fragmentation. 

                                                         

The solutions also have the intelligence to monitor disk IO and the defragmentation will pause to prevent IO latency affecting performance. They are set and forget applications which perform a very well without impact on our server response times."

-Larry Smith, Spokane Regional Health District

Tags:

Defrag | Diskeeper | SAN | V-Locity

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