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.

Solving the IO Blender Effect with Software-Based Caching

by Spencer Allingham 5. July 2018 07:30

First, let me explain exactly what the IO Blender Effect is, and why it causes a problem in virtualized environments such as those from VMware or Microsoft’s Hyper-V.



This is typically what storage IO traffic would look like when everything is working well. You have the least number of storage IO packets, each carrying a large payload of data down to the storage. Because the data is arriving in large chunks at a time, the storage controller has the opportunity to create large stripes across its media, using the least number of storage-level operations before being able to acknowledge that the write has been successful.



Unfortunately, all too often the Windows Write Driver is forced to split data that it’s writing into many more, much smaller IO packets. These split IO situations cause data to be transferred far less efficiently, and this adds overhead to each write and subsequent read. Now that the storage controller is only receiving data in much smaller chunks at a time, it can only create much smaller stripes across its media, meaning many more storage operations are required to process each gigabyte of storage IO traffic.


This is not only true when writing data, but also if you need to read that data back at some later time.

But what does this really mean in real-world terms?

It means that an average gigabyte of storage IO traffic that should take perhaps 2,000 or 3,000 storage IO packets to complete, is now taking 30,000, or 40,000 storage IO packets instead. The data transfer has been split into many more, much smaller, fractured IO packets. Each storage IO operation that has to be generated takes a measurable amount of time and system resource to process, and so this is bad for performance! It will cause your workloads to run slower than they should, and this will worsen over time unless you perform some time and resource-costly maintenance.

So, what about the IO Blender Effect?

Well, the IO Blender Effect can amplify the performance penalty (or Windows IO Performance Tax) in a virtualized environment. Here’s how it works…

 

As the small, fractured IO traffic from several virtual machines passes through the physical host hypervisor (Hyper-V server or VMware ESX server), the hypervisor acts like a blender. It mixes these IO streams, which causes a randomization of the storage IO packets, before sending out what is now a chaotic mess of small, fractured and now very random IO streams out to the storage controller.

It doesn’t matter what type of storage you have on the back-end. It could be direct attached disks in the physical host machine, or a Storage Area Network (SAN), this type of storage IO profile couldn’t be less storage-friendly.

The storage is now only receiving data in small chunks at a time, and won’t understand the relationship between the packets, so it now only has the opportunity to create very small stripes across its media, and that unfortunately means many more storage operations are required before it can send an acknowledgement of the data transfer back up to the Windows operating system that originated it.

How can RAM caching alleviate the problem?

 

Firstly, to be truly effective the RAM caching needs to be done at the Windows operating system layer. This provides the shortest IO path for read IO requests that can be satisfied from server-side RAM, provisioned to each virtual machine. By satisfying as many “Hot Reads” from RAM as possible, you now have a situation where not only are those read requests being satisfied faster, but those requests are now not having to go out to storage. That means less storage IO packets for the hypervisor to blend.

Furthermore, the V-locity® caching software from Condusiv Technologies also employs a patented technology called IntelliWrite®. This intelligently helps the Windows Write Driver make better choices when writing data out to disk, which avoids many of the split IO situations that would then be made worse by the IO Blender Effect. You now get back to that ideal situation of healthy IO; large, sequential writes and reads.

Is RAM caching a disruptive solution?

 

No! Not at all, if done properly.

Condusiv’s V-locity software for virtualised environments is completely non-disruptive to live, running workloads such as SQL Servers, Microsoft Dynamics, Business Information (BI) solutions such as IBM Cognos, or other important workloads such as SAP, Oracle and the such.

In fact, all you need to do to test this for yourself is download a free trialware copy from:

www.condusiv.com/try

Just install it! There are no reboots required, and it will start working in just a couple of minutes. If you decide that it isn’t for you, then uninstall it just as easily. No reboots, no disruption!


Help! I hit “Save” instead of “Save As”!!

by Gary Quan 19. June 2018 06:30

Need to get back to a previous version of a Microsoft Office file before the changes you just made?  Undelete has you covered with its Versioning feature.

Have you or your users ever made some changes to a Word document, Excel spreadsheet, or a PowerPoint presentation, saved it and then realized later that what was saved did not contain the previous work? For example, and a true story, a CEO was working on a PowerPoint file he needed for a Board of Directors presentation that afternoon. He had worked about 4 hours that morning making changes and he was careful to periodically save the changes as he worked. The trouble was the last changes he saved had a large part of his previous changes accidentally overwritten.  The CEO then panicked as he just lost a majority of the 4 hours of work he just put in and was not sure he could redo it in time for his presentation deadline. He immediately called up his IT Manager who indicated the nightly backups would not help as they would not contain any of the changes he made that morning. The IT Manager then remembered he had Undelete installed on this file server. This was mainly to recover accidentally deleted files, but he recalled a Versioning feature that would allow recovery of previous versions of Microsoft Office files. He was then able use Undelete to retrieve the previous version of the CEO’s PowerPoint presentation and recover the work he did that morning. The CEO was extremely happy, and the IT Manager was a ‘hero’ to the CEO!

Another very common scenario is users making edits to original files and then selecting “Save” instead of “Save As” and then the original files are now gone. As an example, a customer had a budget file in Excel and several people had accessed it throughout the day. At some point, someone had inadvertently made multiple changes to it for his department, including deleting sections that were not relevant to his department all the while thinking he was working in his own Save-As copy. Boy, were the other department heads upset! The way our IT Admin customer tells the story it sounded like a riot was about to erupt! Well, he swoops in just in time and recovers the earlier version in minutes and saves the day. We hear stories daily about Word document overwrites that IT Admins are able to recover the previous versions of in just a few minutes, saving users hours of having to recreate their work.

While the most popular functionality of Undelete is the ability to recover accidentally deleted files instantly with the click of a mouse, the Undelete Versioning feature is certainly the runner up, so we wanted to remind users, or prospective users, that it’s also here to save the day for you, too.

The Undelete Versioning feature will automatically save the previous versions of specific file types, including Microsoft Office files. The default is to save the last 5 versions, but this is settable.  Undelete then allows you to see what and when versions were saved and are then easily recoverable. A vital data protection feature to have.

If you already have Undelete Server installed on your file servers, check out the Versioning feature. If you have any of your own “hero” stories you would like to share, email custinfo@condusiv.com

If you don’t have Undelete Server or Undelete Pro yet, you can purchase them from your favorite online reseller or you can buy online from our store http://www.condusiv.com/purchase/Undelete/

 

Tags:

Data Protection | Data Recovery | File Recovery | General | Success Stories | Undelete

How to Recover Lost or Deleted Files BEFORE Resorting to Outsourced Data Recovery

by Gary Quan 1. November 2017 05:46

Here’s a nightmare scenario…a user accidentally deletes irreplaceable or valued files from a network share, and there is no way to recover the data because:

>The file was created or modified then deleted AFTER the last valid backup/snapshot was taken.

>There is NO valid backup or snapshot to recover the data.

>There was NO real-time recovery software like Condusiv’s Undelete® already installed on the file server

>Sending the disk to a professional data recovery center is COSTLY and TIME-CONSUMING.

What do you do? Well, you may be in luck with a little known feature in Condusiv’s Undelete software product known as “Emergency Undelete.” On NTFS (New Technology File system) formatted volumes, which is the default file system used by Windows, there is an unfamiliar characteristic that can be leveraged to recover your lost data.

When a file gets deleted from a Windows volume, the data has not yet been physically removed from the drive. The space where that file data was residing is merely marked as “deleted” or available for use. The original data is there and will remain there until that space is overwritten by new data. That may or may not happen for quite a while. By taking the correct steps, there is an extremely good chance that this ‘deleted’ file can still be recovered. This is where Emergency Undelete comes in.

Emergency Undelete can find deleted files that have not yet been over-written by other files and allow you to recover them. To increase your chances of recovering lost data, here are some best practices to follow as soon as the files have been accidentally deleted.

1. Immediately, reduce or do away with any write activity on the volume(s) you are trying to recover the deleted files from. This will improve your chances of recovering the deleted files.

2. Get Condusiv’s Undelete to leverage its Emergency Undelete feature.  Emergency Undelete is part of the Undelete product package.

3. REMEMBER: You want to prevent any write activity on the volume(s) you are trying to recover the deleted files from, so if you are trying to recover lost files from your system volume, then do one of the following:

a. Copy the Undelete product package to that system, but to a different volume than the one you are recovering lost files from. Run the Undelete install package and it will allow you to run Emergency Undelete directly to recover the lost files.

  

b. If you do not have an extra volume on that system, then place the Undelete product package on a different system, run it and Emergency Undelete will allow you to place the Emergency Undelete package onto a CD or a USB memory stick. You can then place the CD/Memory stick on the system you need to recover from and run it to recover the lost files.

 

 

Now if the lost files do not reside on the system volume, you can just place the Undelete product package on the system volume, run it and select to run Emergency Undelete directly to recover the lost files.

4. When recovering the lost files, recover them to a different volume.

These same steps will also work on FAT (File Allocation Table) formatted storage that is used in many of the memory cards in cameras and phones. So, if some irreplaceable photos or videos were accidentally deleted, you can use these same steps to recover these too. Insert the memory card onto your Windows system, then use Emergency Undelete to recover the lost photos. 

Emergency Undelete has saved highly valuable Microsoft Office documents and priceless photos for thousands of users. It can help in your next emergency, too.

 

Tags:

Data Protection | Data Recovery | Undelete

Recently Discovered SSD Vulnerabilities Could Cripple Global Markets with Data Corruption if Exploited by Attackers

by Brian Morin 15. June 2017 10:38

Recently discovered multi-level cell (MLC) solid-state drive (SSD) vulnerabilities by researchers from Carnegie Mellon University, Seagate, and the Swiss Federal Institute of Technology in Zurich, reveal the first-ever security weakness of its kind against MLC SSDs that store much of the world’s data. Two different types of malicious attacks are reported to corrupt data, leaving much of the world’s data currently exposed while organizations search for answers.

If security experts and data protection experts didn’t have enough to worry about already, the latest discovery from Carnegie Mellon University has set off brand new alarms that could be far more crippling than the recent WannaCry virus or any ransomware attack. In this case, data is not infected or held hostage, but is lost entirely - not even the host SSD hardware can be salvaged after such an attack. This is not simply alarming to organizations that stand the most to lose like financial institutions, but we’re talking about real lives here if patient care is compromised as we saw earlier this month at hospitals across the UK.

In a recently published report by researchers from Carnegie Mellon University, Seagate, and the Swiss Federal Institute of Technology in Zurich, there are two types of malicious attacks that can corrupt data and shorten the lifespan of MLC SSDs – a write attack (“program interference”) and a read attack (“read disturb”). Both attacks inundate the SSD with a large number of operations over a short period of time, which can corrupt data, shorten lifespan, and render an SSD useless to store data in a reliable manner into the future. However, both attacks rely upon native read and write operations from the operating system to the solid-state drive, which is circumvented by Condusiv® I/O reduction software on Windows systems (V-locity®, SSDkeeper®, Diskeeper® 16).

The only reason this story has been covered lightly by the media and not sensationalized across headlines is because no one has died yet or lost a billion dollars. This is a new and very different kind of vulnerability. Protection from this kind of an attack is not something that can be addressed by traditional lines of defense like anti-virus software, firmware upgrades, or OS patches. Since it is cost prohibitive for organizations to “rip-and-replace” multi-cell SSDs with single-cell SSDs, they are forced to rely on data sets that have been “backed-up.” However, what good is restoring data to hardware that can no longer reliably store data?

By acting as the “gatekeeper” between the Windows OS and the underlying SSD device, Condusiv I/O reduction software solutions perform inline optimizations at the OS-level before data is physically written or read from the solid-state drive. As a result, Condusiv’s patented technology is the only known solution that can disrupt “program interference” write operation attacks as well as “read disturb” read operation attacks that would attempt to exploit SSD vulnerabilities and corrupt data. While most known for boosting performance of applications running on Windows systems while extending the longevity of SSDs, Condusiv solutions go a step further as the only line of defense against these malicious attacks.

Condusiv’s patented write optimization engine (IntelliWrite®) mitigates the first vulnerability, “program interference,” by disrupting the write pattern that would otherwise generate errors and corrupt data. IntelliWrite eliminates excessively small writes and subsequent reads by ensuring large, clean contiguous writes from Windows so write operations to solid-state devices are performed in the most efficient manner possible on Windows servers and PCs. An attack could only be successful in the rare instance of limited free space or zero free space on a volume that results in writes occurring natively, circumventing the benefit of IntelliWrite.

Condusiv’s second patented engine (IntelliMemory®) disrupts the second vulnerability, “read disturb,” by establishing a tier-0 caching strategy that leverages idle, available memory to serve hot reads. This renders the “read disturb” attack useless since the storage target for hot reads becomes memory instead of the SSD device. A “read disturb” attack could only be successful in the rare instance that a Windows system is memory constrained and has no idle, available memory to be leveraged for cache.

While organizations use Condusiv software on Windows systems to maintain peak performance and extend the longevity of their SSDs, they can trust Condusiv to protect against malicious attacks that would otherwise corrupt user data and bring great harm to their business and service to customers.

Help! I deleted a file off the network drive!!

by Robin Izsak 31. October 2013 08:01

What if the recycle bin on your clients could be expanded to include file servers? And what if you could enable your users to recover their own files with self-service recovery? You would never have to dig through backups to restore files again, or schedule incessant snapshots to protect data.

One of the most persistent—and annoying—help desk calls is to help users recover files accidentally deleted off network drives, or support users who ‘saved over’ a PowerPoint they need for a meeting—in 15 minutes.

There are some pretty serious holes in true continuous data protection: First, any data that was created between backups might not be recoverable. Second, who wants to dig through backups anyway? Third, you’d have to schedule an insane amount of snapshots to protect every version of every file. Fourth, the Windows recycle bin doesn’t catch files deleted off a network drive, which is how most of us work in the real world—networks, clouds—not local drives.

Check out our latest guide that explains the gap between backup and the Windows recycle bin, and how to bridge that gap with Undelete® to ensure continuous data protection and self-service file recovery.

Meet the recycle bin for file servers. You’re welcome.

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