Tag: locality of reference

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I/O, I/O how well do you know good bad ugly server storage I/O iops?

How well do you know good bad ugly I/O iops?

server storage i/o iops activity data infrastructure trends

Updated 2/10/2018

There are many different types of server storage I/O iops associated with various environments, applications and workloads. Some I/Os activity are iops, others are transactions per second (TPS), files or messages per time (hour, minute, second), gets, puts or other operations. The best IO is one you do not have to do.

What about all the cloud, virtual, software defined and legacy based application that still need to do I/O?

If no IO operation is the best IO, then the second best IO is the one that can be done as close to the application and processor as possible with the best locality of reference.

Also keep in mind that aggregation (e.g. consolidation) can cause aggravation (server storage I/O performance bottlenecks).

aggregation causes aggravation
Example of aggregation (consolidation) causing aggravation (server storage i/o blender bottlenecks)

And the third best?

It’s the one that can be done in less time or at least cost or effect to the requesting application, which means moving further down the memory and storage stack.

solving server storage i/o blender and other bottlenecks
Leveraging flash SSD and cache technologies to find and fix server storage I/O bottlenecks

On the other hand, any IOP regardless of if for block, file or object storage that involves some context is better than those without, particular involving metrics that matter (here, here and here [webinar] )

Server Storage I/O optimization and effectiveness

The problem with IO’s is that they are a basic operations to get data into and out of a computer or processor, so there’s no way to avoid all of them, unless you have a very large budget. Even if you have a large budget that can afford an all flash SSD solution, you may still meet bottlenecks or other barriers.

IO’s require CPU or processor time and memory to set up and then process the results as well as IO and networking resources to move data too their destination or retrieve them from where they are stored. While IO’s cannot be eliminated, their impact can be greatly improved or optimized by, among other techniques, doing fewer of them via caching and by grouping reads or writes (pre-fetch, write-behind).

server storage I/O STI and SUT

Think of it this way: Instead of going on multiple errands, sometimes you can group multiple destinations together making for a shorter, more efficient trip. However, that optimization may also mean your drive will take longer. So, sometimes it makes sense to go on a couple of quick, short, low-latency trips instead of one larger one that takes half a day even as it accomplishes many tasks. Of course, how far you have to go on those trips (i.e., their locality) makes a difference about how many you can do in a given amount of time.

Locality of reference (or proximity)

What is locality of reference?

This refers to how close (i.e., its place) data exists to where it is needed (being referenced) for use. For example, the best locality of reference in a computer would be registers in the processor core, ready to be acted on immediately. This would be followed by levels 1, 2, and 3 (L1, L2, and L3) onboard caches, followed by main memory, or DRAM. After that comes solid-state memory typically NAND flash either on PCIe cards or accessible on a direct attached storage (DAS), SAN, or NAS device. 

server storage I/O locality of reference

Even though a PCIe NAND flash card is close to the processor, there still remains the overhead of traversing the PCIe bus and associated drivers. To help offset that impact, PCIe cards use DRAM as cache or buffers for data along with meta or control information to further optimize and improve locality of reference. In other words, this information is used to help with cache hits, cache use, and cache effectiveness vs. simply boosting cache use.

SSD to the rescue?

What can you do the cut the impact of IO’s?

There are many steps one can take, starting with establishing baseline performance and availability metrics.

The metrics that matter include IOP’s, latency, bandwidth, and availability. Then, leverage metrics to gain insight into your application’s performance.

Understand that IO’s are a fact of applications doing work (storing, retrieving, managing data) no matter whether systems are virtual, physical, or running up in the cloud. But it’s important to understand just what a bad IO is, along with its impact on performance. Try to identify those that are bad, and then find and fix the problem, either with software, application, or database changes. Perhaps you need to throw more software caching tools, hypervisors, or hardware at the problem. Hardware may include faster processors with more DRAM and faster internal busses.

Leveraging local PCIe flash SSD cards for caching or as targets is another option.

You may want to use storage systems or appliances that rely on intelligent caching and storage optimization capabilities to help with performance, availability, and capacity.

Where to gain insight into your server storage I/O environment

There are many tools that you can be used to gain insight into your server storage I/O environment across cloud, virtual, software defined and legacy as well as from different layers (e.g. applications, database, file systems, operating systems, hypervisors, server, storage, I/O networking). Many applications along with databases have either built-in or optional tools from their provider, third-party, or via other sources that can give information about work activity being done. Likewise there are tools to dig down deeper into the various data information infrastructure to see what is happening at the various layers as shown in the following figures.

application storage I/O performance
Gaining application and operating system level performance insight via different tools

windows and linux storage I/O performance
Insight and awareness via operating system tools on Windows and Linux

In the above example, Spotlight on Windows (SoW) which you can download for free from Dell here along with Ubuntu utilities are shown, You could also use other tools to look at server storage I/O performance including Windows Perfmon among others.

vmware server storage I/O
Hypervisor performance using VMware ESXi / vsphere built-in tools

vmware server storage I/O performance
Using Visual ESXtop to dig deeper into virtual server storage I/O performance

vmware server storage i/o cache
Gaining insight into virtual server storage I/O cache performance

Wrap up and summary

There are many approaches to address (e.g. find and fix) vs. simply move or mask data center and server storage I/O bottlenecks. Having insight and awareness into how your environment along with applications is important to know to focus resources. Also keep in mind that a bit of flash SSD or DRAM cache in the applicable place can go along way while a lot of cache will also cost you cash. Even if you cant eliminate I/Os, look for ways to decrease their impact on your applications and systems.

Where To Learn More

View additional NAS, NVMe, SSD, NVM, SCM, Data Infrastructure and HDD related topics via the following links.

Additional learning experiences along with common questions (and answers), as well as tips can be found in Software Defined Data Infrastructure Essentials book.

Software Defined Data Infrastructure Essentials Book SDDC

What This All Means

>Keep in mind: SSD including flash and DRAM among others are in your future, the question is where, when, with what, how much and whose technology or packaging.

Ok, nuff said, for now.

Gs

Greg Schulz – Microsoft MVP Cloud and Data Center Management, VMware vExpert 2010-2017 (vSAN and vCloud). Author of Software Defined Data Infrastructure Essentials (CRC Press), as well as Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press), Resilient Storage Networks (Elsevier) and twitter @storageio. Courteous comments are welcome for consideration. First published on https://storageioblog.com any reproduction in whole, in part, with changes to content, without source attribution under title or without permission is forbidden.

All Comments, (C) and (TM) belong to their owners/posters, Other content (C) Copyright 2006-2024 Server StorageIO and UnlimitedIO. All Rights Reserved. StorageIO is a registered Trade Mark (TM) of Server StorageIO.

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Is SSD dead? No, however some vendors might be

Storage I/O trends

Is SSD dead? No, however some vendors might be

In a recent conversation with Dave Raffo about the nand flash solid state disk (SSD) market, we talked about industry trends, perspectives and where the market is now as well as headed. One of my comments is, has been and will remain that the industry has still not reached anywhere near full potential for deployment of SSD for enterprise, SMB and other data storage needs. Granted, there is broad adoption in terms of discussion or conversation and plenty of early adopters.

SSD and in particular nand flash is anything but dead, in fact in the big broad picture of things, it is still very early in the game. Sure, for those who cover and crave the newest, latest and greatest technology to talk about, nand flash SSD might seem old, yesterday news, long in the tooth and time for something else. However, for those who are focused on deployment vs. adoption such as customers, in general, nand flash SSD in its many packaging options has still not yet reached its full potential.

Despite the hype, fanfare from CEOs or their evangelist along with loyal followers of startups that help drive industry adoption (e.g. what is talked about), there is still lots of upside growth in the customer drive industry deployment (actually buying, installing and using) for nand flash SSD.

What about broad customer deployments?

Sure, there are the marquee customer success stories that you need a high-capacity SAS or SATA drive to hold the YouTube videos, slide decks, press releases for.

However, have we truly, reached broad customer deployment or broad industry adoption?

Hence, I see more startups coming into the market space, and some exiting on their own, via mergers and acquisition or other means.

Will we see a feeding frenzy or IPO craze as with earlier hype cycles of technologies, IMHO there will be some companies that get the big deal, some will survive as new players running as a business vs. running to be acquired or IPO. Others will survive by evolving into something else while others will join the where are they now list.

If you are a SSD startup, CEO, CxO, or marketer, their PR, evangelist or loyal follower do not worry as the SSD market and even nand flash is far from being dead. On the other hand, if you think that it has hit its full stride, you are missing either the bigger picture, or too busy patting yourselves on the back for a job well done. There is much more opportunity out there and not even all the low hanging fruit has been picked yet.

Check out the conversation with Dave Raffo along with comments from others here.

Related links on storage IO metrics and SSD performance
What is the best kind of IO? The one you do not have to do
Is SSD dead? No, however some vendors might be
Storage and IO metrics that matter
IO IO it is off to Storage and IO metrics we go
SSD and Storage System Performance
Speaking of speeding up business with SSD storage
Are Hard Disk Drives (HDD’s) getting too big?
Has SSD put Hard Disk Drives (HDD’s) On Endangered Species List?
Why SSD based arrays and storage appliances can be a good idea (Part I)
IT and storage economics 101, supply and demand
Researchers and marketers dont agree on future of nand flash SSD
EMC VFCache respinning SSD and intelligent caching (Part I)
SSD options for Virtual (and Physical) Environments Part I: Spinning up to speed on SSD
SSD options for Virtual (and Physical) Environments Part II: The call to duty, SSD endurance
SSD options for Virtual (and Physical) Environments Part III: What type of SSD is best for you?
SSD options for Virtual (and Physical) Environments Part IV: What type of SSD is best for your needs

Ok, nuff said for now

Cheers Gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press, 2011), The Green and Virtual Data Center (CRC Press, 2009), and Resilient Storage Networks (Elsevier, 2004)

twitter @storageio

All Comments, (C) and (TM) belong to their owners/posters, Other content (C) Copyright 2006-2012 StorageIO and UnlimitedIO All Rights Reserved

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More storage and IO metrics that matter

It is great to see more conversations and coverage around storage metrics that matter beyond simply focusing on cost per GByte or TByte (e.g. space capacity). Likewise, it is also good to see conversations expanding beyond data footprint reduction (DFR) from a space capacity savings or reduction ratio to also address data movement and transfer rates. Also good to see is increase in discussion around input/output operations per section (IOPs) tying into conversations from virtualization, VDI, cloud to Sold State Devices (SSD).

Other storage and IO metrics that matter include latency or response time, which is how fast work is done, or time spent. Latency also ties to IOPS in that as more work arrives to be done (IOPS) of various size, random or sequential, reads or writes, queue depths are an indicator of how well work is flowing. Another storage and IO metric that matters is availability because without it, performance or capacity can be affected. Likewise, without performance, availability can be affected.

Needless to say that I am just scratching the surface here with storage and IO metrics that matter for physical, virtual and cloud environments from servers to networks to storage.

Here is a link to a post I did called IO, IO, it is off to storage and IO metrics we go that ties in themes of performance measurements and solid-state disk (SSD) among others. Also check out this piece about why VASA (VMware storage analysis metrics) is important to have your VMware CASA along with Windows boot storage and IO performance for VDI and traditional planning purposes.

Check out this post about metrics and measurements that matter along with this conversation about IOPs, capacity, bandwidth and purchasing discussion topics.

Related links on storage IO metrics and SSD performance
What is the best kind of IO? The one you do not have to do
Is SSD dead? No, however some vendors might be
Storage and IO metrics that matter
IO IO it is off to Storage and IO metrics we go
SSD and Storage System Performance
Speaking of speeding up business with SSD storage
Are Hard Disk Drives (HDD’s) getting too big?
Has SSD put Hard Disk Drives (HDD’s) On Endangered Species List?
Why SSD based arrays and storage appliances can be a good idea (Part I)
IT and storage economics 101, supply and demand
Researchers and marketers dont agree on future of nand flash SSD
EMC VFCache respinning SSD and intelligent caching (Part I)
SSD options for Virtual (and Physical) Environments Part I: Spinning up to speed on SSD
SSD options for Virtual (and Physical) Environments Part II: The call to duty, SSD endurance
SSD options for Virtual (and Physical) Environments Part III: What type of SSD is best for you?
SSD options for Virtual (and Physical) Environments Part IV: What type of SSD is best for your needs

Ok, nuff said for now

Cheers Gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press, 2011), The Green and Virtual Data Center (CRC Press, 2009), and Resilient Storage Networks (Elsevier, 2004)

twitter @storageio

All Comments, (C) and (TM) belong to their owners/posters, Other content (C) Copyright 2006-2012 StorageIO and UnlimitedIO All Rights Reserved

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What is the best kind of IO? The one you do not have to do

What is the best kind of IO? The one you do not have to do

data infrastructure server storage I/O trends

Updated 2/10/2018

What is the best kind of IO? If no IO (input/output) operation is the best IO, than the second best IO is the one that can be done as close to the application and processor with best locality of reference. Then the third best IO is the one that can be done in less time, or at least cost or impact to the requesting application which means moving further down the memory and storage stack (figure 1).

Storage and IO or I/O locality of reference and storage hirearchy
Figure 1 memory and storage hierarchy

The problem with IO is that they are basic operation to get data into and out of a computer or processor so they are required; however, they also have an impact on performance, response or wait time (latency). IO require CPU or processor time and memory to set up and then process the results as well as IO and networking resources to move data to their destination or retrieve from where stored. While IOs cannot be eliminated, their impact can be greatly improved or optimized by doing fewer of them via caching, grouped reads or writes (pre-fetch, write behind) among other techniques and technologies.

Think of it this way, instead of going on multiple errands, sometimes you can group multiple destinations together making for a shorter, more efficient trip; however, that optimization may also take longer. Hence sometimes it makes sense to go on a couple of quick, short low latency trips vs. one single larger one that takes half a day however accomplishes many things. Of course, how far you have to go on those trips (e.g. locality) makes a difference of how many you can do in a given amount of time.

What is locality of reference?

Locality of reference refers to how close (e.g location) data exists for where it is needed (being referenced) for use. For example, the best locality of reference in a computer would be registers in the processor core, then level 1 (L1), level 2 (L2) or level 3 (L3) onboard cache, followed by dynamic random access memory (DRAM). Then would come memory also known as storage on PCIe cards such as nand flash solid state device (SSD) or accessible via an adapter on a direct attached storage (DAS), SAN or NAS device. In the case of a PCIe nand flash SSD card, even though physically the nand flash SSD is closer to the processor, there is still the overhead of traversing the PCIe bus and associated drivers. To help offset that impact, PCIe cards use DRAM as cache or buffers for data along with Meta or control information to further optimize and improve locality of reference. In other words, help with cache hits, cache use and cache effectiveness vs. simply boosting cache utilization.

Where To Learn More

View additional NAS, NVMe, SSD, NVM, SCM, Data Infrastructure and HDD related topics via the following links.

Additional learning experiences along with common questions (and answers), as well as tips can be found in Software Defined Data Infrastructure Essentials book.

Software Defined Data Infrastructure Essentials Book SDDC

What This All Means

What can you do the cut the impact of IO

  • Establish baseline performance and availability metrics for comparison
  • Realize that IOs are a fact of IT virtual, physical and cloud life
  • Understand what is a bad IO along with its impact
  • Identify why an IO is bad, expensive or causing an impact
  • Find and fix the problem, either with software, application or database changes
  • Throw more software caching tools, hyper visors or hardware at the problem
  • Hardware includes faster processors with more DRAM and fast internal busses
  • Leveraging local PCIe flash SSD cards for caching or as targets
  • Utilize storage systems or appliances that have intelligent caching and storage optimization capabilities (performance, availability, capacity).
  • Compare changes and improvements to baseline, quantify improvement

Ok, nuff said, for now.

Gs

Greg Schulz – Microsoft MVP Cloud and Data Center Management, VMware vExpert 2010-2017 (vSAN and vCloud). Author of Software Defined Data Infrastructure Essentials (CRC Press), as well as Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press), Resilient Storage Networks (Elsevier) and twitter @storageio. Courteous comments are welcome for consideration. First published on https://storageioblog.com any reproduction in whole, in part, with changes to content, without source attribution under title or without permission is forbidden.

All Comments, (C) and (TM) belong to their owners/posters, Other content (C) Copyright 2006-2024 Server StorageIO and UnlimitedIO. All Rights Reserved. StorageIO is a registered Trade Mark (TM) of Server StorageIO.