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Diskspd performance testing

Deploying a new system requires a rigorous process in order to ensure stability and performance. In order to keep the cycle time of that process to a minimum, automation is key. The more thorough your checklist is, the less chance for surprises once your system is up and running with mission critical workload. The goal of this particular post is to focus on the storage performance testing piece that goes into preparing a new system for rollout.

The only exception that comes to mind at this point in time is Exchange. If you want the absolute latest version, you will need to download the source code from the GitHub site here and compile the code yourself.

After covering this process, the post will then provide a concrete example of how you would tackle IO baselining for a SQL Server workload. The first step in planning a good storage test suite for your storage is to understand it.

To give you a sense of what you might want to consider while reviewing your storage platform, here are some of the things that will influence how you will be testing and the test results you will obtain:. Again, in the spirit of selecting the right tests to perform against your storage platform, you need to have a good understanding of the IO patterns of the applications that will run on top of it. You need to identify the following:.

This step in the process should be straightforward. It boils down to launching the script built in the previous step and wait for all the test cases to complete. Once you have run the tests using diskspd. While testing your storage platform, you will most likely discover things that are not working as expected.

This will result in configuration changes along the way. The key things to understand here are the following:. The goal here is to be methodical. If you introduce multiple changes at the same time, you run into the possibility that one of those changes causes a regression in performance. The goal here is to be able to pull those numbers quickly in the event of a performance issue. When that happens, simply re-run your automated performance tests and compare with the previous results.

I will now guide you through a simple example of how you would apply the process above. This means the IOs are mostly random reads with a bit of sequential writes for log operations. Based on our understanding of the workload and the hardware, we need to create diskspd tests that will generate random reads that are typical to SQL Server and sequential write tests to accommodate the log operations IO.

This translates to the following tests:.

Customizing tests

Note this switch is only used in the first test as all subsequent tests will reuse the file created by the first test. Once your diskspd commands have been prepared and save in a batch or PowerShell script file, simply run the tests.

I recommend running the test a few times to let the. This section is useful to look at exactly which test was being run for this particular result file.

We can see where the test file was located, the IO block size used, the number of threads if the test was a read or a write test and the test duration. This is the first section that starts to show interesting data. Here you can see how many threads were used but also how many processors were available at the time of the test.This site uses cookies for analytics, personalized content and ads.

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diskspd performance testing

My contributions. DiskSpd: A Robust Storage Performance Tool A feature-rich and versatile storage performance tool, DiskSpd combines robust and granular IO workload definitions with flexible runtime and output options, creating an ideal tool for synthetic storage subsystem testing and validation.

Downloaded 19, times. Favorites Add to favorites. Category Storage. Sub-category Files. License Custom. Tags PerformanceStorageTesting. This script is tested on these platforms by the author. It is likely to work on other platforms as well. If you try it and find that it works on another platform, please add a note to the script discussion to let others know.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

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If nothing happens, download the GitHub extension for Visual Studio and try again. In addition to the tool itself, this repository hosts measurement frameworks which utilize DiskSpd.

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Analyzing I/O Subsystem Performance Glenn Berry

Sign up. Branch: master. Find file. Sign in Sign up. Launching Xcode If nothing happens, download Xcode and try again. Latest commit. Latest commit 6d88fb9 Mar 27, What's New? Among other things, this allows buffered write-through to be specified -Sbw.

Includes an analysis script which provides the linear model for each off of the results. You signed in with another tab or window.

Reload to refresh your session. You signed out in another tab or window. Pull request for 2. Sep 28, Mar 26, How do you know what level of performance to expect from your tiered storage spaces in Windows Server, and how can you tell whether the storage tiers are delivering the needed performance after you deploy your workloads?

This topic describes how to run a series of performance tests against synthetic workloads, using DiskSpd. When you test the performance of a newly created tiered storage space, your goal should be to baseline ideal storage tiers performance by testing the performance of the SSD tier only. For optimal performance, the SSD tier should be large enough to accommodate the entire working set all active data of workloads that use the space. Storage Tiers Optimization, which is performed at a.

During a phased migration, the Storage Tier Optimization Report can provide diagnostics for determining the SSD tier capacity and Storage Tiers Optimization frequency needed to meet performance requirements of the workloads. There's really no way to accurately predict performance of both the SSD tier and the HDD tier working together by using a synthetic workload. For that, you will need to use the Storage Tier Optimization Report and monitor performance counters for Storage Spaces, including those for the Storage Tiers object and the Storage Write Cache object, to characterize daily activity of the deployed workloads as they become stable and predictable.

The DiskSpd. DiskSpd provides flexible options for emulating performance behavior of synthetic random or sequential workloads. It can be used to test the performance of physical disks, partitions, or files in a storage subsystem.

Additional DiskSpd documentation, in both. Be sure to use DiskSpd version 2. It's a good idea always to install the latest release before you run DiskSpd tests. To provide enough data to fully exercise the underlying SSDs, DiskSpd will create a 64 GB data file, the size of an average virtual machine. To exercise all layers of the storage stack during testing, the tests are run on a virtual machine deployed to the storage space.

We test the performance of the SSD tier only, to find out the high end of potential performance of a tiered storage space. To get accurate performance data for the SSD drives, each run of the DiskSpd command includes a 5-minute warmup time followed by 10 minutes of data collection.

diskspd performance testing

If you shorten the warmup time, you might be observing SSD drive initialization, before the drives reach a steady state. And, of course, the longer the sampling period, the greater the reliability of your results will be and the less variability if you repeat a test.

That will tell you the top performance that the physical disks are capable of for the same synthetic workload, without the overhead introduced by each additional layer of the storage stack. You can do this before you create the storage pool, you can remove a disk from the pool for testing, or you can test an extra SSD of the same model.

Our tests are run on a clustered file server configured as a scale-out file server SOFSwith the configuration described in the following table. You will see references to these configurations in the procedures.

Before you prepare for the DiskSpd tests, we assume that you already have a new storage space that you want to test, and that you have completed the following tasks:.The SQLPerformance. CrystalDiskMark was recently rewritten to use Microsoft DiskSpd for its testing, which makes it an even more valuable tool for your initial storage subsystem testing efforts. It is extremely useful for synthetic storage subsystem testing when you want a greater level of control than that available in CrystalDiskMark.

Now, we are going to dive a little deeper into how to actually use Microsoft DiskSpd to test your storage subsystem without using CrystalDiskMark 4. In order to do this, you'll need to download and unzip DiskSpd. To make things easier, I always copy the desired diskspd. In most cases you will want the bit version of DiskSpd from the amd64fre folder. Once you have the diskspd. You will also want to specify the test file location and the file name for the results at the end of the line.

Here is an example command line:. It will save the results of the test to a text file called DiskSpeedResults. Figure 1: Example command line for DiskSpd. Running the test starts with a default five second warm up time before any measurements actually startand then the actual test will run for the specified duration in seconds with a default cool down time of zero seconds.

When the test finishes, DiskSpd will provide a description of the test and the detailed results. By default this will be a simple text summary in a text file using the file name that you specified, which will be in the same directory as the diskspd executable. Figure 2: Example DiskSpd test results. The first section of the results gives you the exact command line that was used for the test, then specifies all of the input parameters that were used for the test run which include the default values that may not have been specified in the actual command line.

Next, the test results are shown starting with the actual test time, thread count, and logical processor count. The CPU section shows the CPU utilization for each logical processor, including user and kernel time, for the test interval. The more interesting part of the test results comes next. The results for each thread should be very similar in most cases. Rather than initially focusing on the absolute values for each measurement, I like to compare the values when I run the same test on different logical drives, after changing the location of the test file in the command linewhich lets you compare the performance for each logical drive.

The last section of the test results is even more interesting. It shows a percentile analysis of the distribution of the latency test results starting from the minimum value in milliseconds going up to the maximum value in milliseconds, broken out for reads, writes, and total latency. The reason why the values for the higher percentile rows are the same is because this test had a relatively low number of total operations.

What you want to look for in these results is the point where the values make a large jump. Figure 3: Latency results distribution.

DiskSpd: A Robust Storage Performance Tool

As you can see, running DiskSpd is actually pretty simple once you understand what the basic parameters mean and how they are used. Not only can you run DiskSpd from an old-fashioned command line, you can also run it using PowerShell. The more complicated part of using DiskSpd is analyzing and interpreting the results, which is something I will cover in a future article. It is a completely different testing tool. Nice post.

I like to use Diskspd for testing basic storage performance on slow SQL server systems. It is fast, easy to use, and the results are usually pretty clear: Very high latency, low number of IOPS, etc.

Should the SQL Server be idle when this is used? I am looking to test new storage and want to benchmark our existing SAN in production and then compare to the same tests performed on evaluation storage that my organisation will be looking to purchase. Should I have the production SQL instances shutdown and no other work being performed on then whilst testing? Nice 1! Been having issues with our SAN. SAN Team will be reconfiguring for better results.The following sections explain how you can use the DiskSpd parameters to customize tests so that they more closely emulate the performance factors that your environment requires.

The default measured test duration is 10 seconds. The actual measured test duration may be slightly longer than the requested time because of additional thread synchronization and precision of the operating system's sleep methods. The actual duration of the test is reported as part of the results.

The default warm up duration is 5 seconds and can be changed using the -W parameter for example, -W10 sets a second warm up. A cool-down period can be specified using the -C parameter; for example, -C5 adds a 5 second cool-down period. The default cool-down time is 0 seconds. A use case for cool-down is to ensure that, especially in multi-system tests, all instances of DiskSpd are active during each instance's measurement period.

Specify a cool-down which is at least as long as the time taken to launch the DiskSpd instances on the systems providing the test. To control software operating system and hardware caching, use the -S parameter. There are five modifiers that can be applied:. The -Sh parameter disables both software caching and hardware write-caching and has the same constraints that apply to disabling software caching.

The combination of -Suw is equivalent.

diskspd performance testing

Write-through may be independently specified with -Sw. Stated in isolation, this the same as explicitly using -Sbw for cached write-through. Devices with persistent write caches — certain enterprise flash drives and most storage arrays — will complete write-through writes when the write is stable in cache. The -Sr parameter is specific to running tests over remote file systems such as SMB and disables the local cache while leaving the remote system's cache enabled.

This can be useful when investigating the remote file system's wire transport performance and behavior, allowing a wire-limited read test to occur without needing extremely fast storage subsystems.

Storage Performance Baseline with Diskspd

This can be combined with w -Srw to specify write-through on the server. These hints are generally applicable only to files and only if software caching is enabled for the test. They are equivalent to using the following flags with the Windows CreateFile function:. Please see the operating system documentation for the CreateFile function for the behavioral definitions of these options.

Note that the random access and sequential-only hints indicate access patterns which are exclusive of the other and combining them may result in unusual behavior. The temporary file attribute only takes effect if the file is newly created see Create test files automatically and has the effect of delaying background cache writes until memory pressure requires progress or the file is closed.

diskspd performance testing

In conventional use, this allows a spill file to be created on the assumption that it will be quickly deleted, avoiding all writes. This may be useful in focused performance tests for similar reasons. The default value is 64KiB. All offsets are aligned to the size specified with the -r parameter.

If you use the -r parameter without specifying the size, offsets are block-aligned. The block size is set with the -b parameter. If both -r and -s are specified, -r overrides -s. If multiple threads operate on a single target, the threads will operate independently and the target will see multiple sequential streams. If the optional interlocked i qualifier is used, -sia single interlocked offset is shared between all threads operating on a given target.But if you want to use it, and to avoid some traps that will invalidate your testing, here are some tips.

So be aware of this. This is no longer required with DiskSPD. Such as -Z 1G for example. If you use -Z by itself then it will generate just zeros. To get the most out of your testing I would recommend that you test different IO patterns, different IO sizes, different amount of outstanding IO, and across a single and multiple drive letters.

Be aware that specifying too many outstanding IO operations will just overload the operating system queues and does not allow you to measure the underlying storage subsystem at all. Usually the SCSI driver will have a limited queue depth per drive of 32, potentially higher depending on if you are in a virtual or physical environment and what driver you are using.

The Windows Storport driver has a queue depth limit per drive of If you exceed any of these limits your performance suffers and your latency spikes. This tries to reduce the queue depth contention that would otherwise result. This will allow you to cover your bases in terms of some of the common IO sizes that you will see in your database.

The IO size is set to 64kb in this case -b64k. If you have a striped volume made up of a number of physical disk devices you can use more threads per file.

We disable hardware and software caching with -h, and we measure latency statistics with -L. You will need to use another tool to gather CPU performance data, such as Perfmon. If you want to make your testing more realistic you might want to grab the details from using a tool such as procmon in Windows, or if in a VMware environment vscsiStats. But to get an indication of storage performance, tools such as DiskSPD are useful, even though they do not give an accurate or full picture of performance that will impact applications.

Once you have a baseline you can use it as a point of comparison against any changes or upgrades for your system, and when changing platforms. But to ensure validity of testing you should limit the number of variables between tests and data sets. All rights reserved. Not to be reproduced for commercial purposes without written permission.

Someone asked me about DiskSpd recently and I had no idea what it […]. This site uses Akismet to reduce spam. Learn how your comment data is processed. April 29, Menu Skip to content. Like this: Like Loading James Youkhanis August 9, at am Permalink. Can i run microsoft disk speed on a current production server?

Will it impact my servers? It depends on your architecture. It could impact existing servers. Best to run it off hours.

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