Storage bus cache on Storage Spaces (2023)

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Applies to: Windows Server 2022

The storage bus cache for standalone servers can significantly improve read and write performance, while maintaining storage efficiency and keeping the operational costs low. Similar to its implementation for Storage Spaces Direct, this feature binds together faster media (for example, SSD) with slower media (for example, HDD) to create tiers. By default, only a portion of the faster media tier is reserved for the cache.

ResiliencyCache type
None (Simple space)Read and write
Mirror accelerated parityRead

If your system does not require resiliency or has external backups, the storage bus cache will support both read and write caching. For resilient systems, the storage bus cache will only serve as a read cache and it is recommended to pick ReFS Mirror-accelerated parity as the volume resiliency. This combination improves random read performance as data is read from the parity tier and cached on the faster mirror tier. The mirror tier also provides write caching capabilities if the Provision Mode is set to Shared (default).

Storage bus cache on Storage Spaces (1)

In this tutorial, you learn about:

  • What the storage bus cache is
  • How to enable the storage bus cache
  • Managing the cache after deployment


Storage bus cache on Storage Spaces (2) Consider storage bus cache if:

  • Your server runs Windows Server 2022; and
  • Your server has 2 media/ drive types, one of which must be HDD (for example: SSD+HDD or NVMe+HDD); and
  • Your server has the Failover Clustering feature installed

Storage bus cache on Storage Spaces (3) You can't use storage bus cache if:

  • Your server runs Windows Server 2016 or 2019; or
  • Your server has an all flash configuration; or
  • You server is a member of a Failover Cluster


This feature requires your server to have the Failover Clustering feature installed but your server cannot be a part of a Failover Cluster.

(Video) Testing Storage Spaces Parity on Server 2022, Has performance been improved?

Feature overview

This section explains what each configurable field of the storage bus cache is and applicable values.


The output should resemble below when not enabled:

ProvisionMode : SharedSharedCachePercent : 15CacheMetadataReserveBytes : 34359738368CacheModeHDD : ReadWriteCacheModeSSD : WriteOnlyCachePageSizeKBytes : 16Enabled : False


For general use, default settings are recommended. Any changes must be made prior to enabling the storage bus cache.

Provision Mode

This field determines if the entire faster media tier or only a portion of it will be used for caching. This field cannot be modified after enabling the storage bus cache.

  • Shared (default): The cache will only take up a portion of the faster media tier. The exact percentage is configurable by the Shared Cache Percentage field below.
  • Cache: Dedicate majority of the faster media tier to caching as opposed to only a portion. The implementation is similar to the storage bus cache in Storage Spaces Direct.

This field is only applicable when the Provision Mode is set to Shared. The default value is 15% and the field can be set from 5% to 90%. A value over 50% is not recommended when using mirror accelerated parity volumes as there needs to be a balance between the cache and the mirror tier.


This field refers to the state of the storage bus cache and can either be True or False.

Advanced fields


Changes to these fields are not recommended. Adjustments after enabling the storage bus cache cannot be made.

(Video) Windows 11/10 Storage Spaces: Use ReFS, build resiliency and data protection

  • Cache metadata reserve bytes: The amount of disk space (in bytes) reserved for Storage Spaces. This field is only applied if the Provision Mode is Cache.

  • Cache mode HDD: The default is to allow the HDD capacity devices to cache reads and writes. For Simple spaces, this setting can be set to ReadWrite or WriteOnly.

  • Cache mode SSD: For future use when all flash systems are supported. The default is to allow the SSD capacity devices to cache writes only.

  • Cache page size KBytes: This field can be set to 8, 16 (default), 32 and 64.

Enable storage bus cache in PowerShell

This section is a step-by-step guide on how to enable the storage bus cache for your stand-alone server in PowerShell.

  1. Import the module

    Import-Module StorageBusCache 
  2. Configure storage bus cache settings

    Default settings are recommended, skip this step to continue with the defaults.


    If configuration is needed, do so before enabling the storage bus cache. Refer to Feature overview section for details of the fields.

    (Video) How I setup and use Storage Spaces parity in Windows 10

  3. Check the drive status


    The output should resemble the image below, where the Number column shows values under 500 and the CanPool column shows True for all non-boot drives.

    Storage bus cache on Storage Spaces (4)

  4. Enable storage bus cache


    This step will:

    • Create a storage pool with all the available drives
    • Bind the fast and slow media and form the cache
    • Add the storage bus cache with default or custom settings

    You can run Get-StoragePool to see the name of the storage pool and Get-PhysicalDisk again to see the effects of enabling storage bus cache. The output should resemble the image below, where the Number column shows values over 500 (indicating the drive is claimed by the storage bus) and the CanPool column now shows False for all non-boot drives. If the ProvisionMode was set to Cache prior to enabling, the Usage column will show as Journal for the faster drives.

    Storage bus cache on Storage Spaces (5)

  5. Check the storage bus cache state

    Check that the fields are correct and the Enabled field is now set to true.


    The output should resemble below:

    (Video) Storage Spaces Direct Overview

    ProvisionMode : SharedSharedCachePercent : 15CacheMetadataReserveBytes : 34359738368CacheModeHDD : ReadWriteCacheModeSSD : WriteOnlyCachePageSizeKBytes : 16Enabled : True

Now the storage bus cache has been successfully enabled, the next step is to create a volume.

Create a volume

Volumes with resiliency:

The PowerShell cmdlet below creates a 1TiB mirror-accelerated parity volume with a Mirror:Parity ratio of 20:80, which is the recommended configuration for most workloads. For more information, see Mirror-accelerated parity.

New-Volume –FriendlyName "TestVolume" -FileSystem ReFS -StoragePoolFriendlyName Storage* -StorageTierFriendlyNames MirrorOnSSD, ParityOnHDD -StorageTierSizes 200GB, 800GB

Volumes without resiliency:

The PowerShell cmdlet below creates a 1TB Simple volume that cannot tolerate any disk failure. Both read and write caching is supported.

New-Volume -FriendlyName "TestVolume" -FileSystem ReFS -StoragePoolFriendlyName Storage* -ResiliencySettingName Simple -Size 1TB

Making changes after enabling storage bus cache

After running Enable-StorageBusCache, the Provision mode, Shared cache percent, Cache metadata reserve bytes, Cache mode HDD, Cache mode SSD, and Cache page size cannot be modified. Limited changes can be made to the physical setup, below are some common scenarios.

Adding or replacing capacity drives (HDDs)

Once the drive has been manually added, run the cmdlet below to finish the intake process.


Adding or replacing cache drives (NVMes or SSDs)

There is no cmdlet to unbind/rebind existing bindings and balance out the relationship. The steps below will cause the existing read cache to be lost.


Check and balance cache and capacity bindings

Use the following cmdlet to check the existing cache and capacity bindings.


In the example below, the first column lists out capacity drives and the third column lists out the cache drives that they are bound to. Follow the instructions in Adding or replacing cache drives to balance, the existing cache will not be preserved.

Storage bus cache on Storage Spaces (6)

Storage bus cache FAQ

This section answers frequently asked questions about the storage bus cache on Windows Server 2022

Why does the Failover Clustering feature need to be installed when the server is not a part of a Failover Cluster?

This feature is designed for standalone servers but built on top of the storage bus layer (SBL) cache for Storage Spaces Direct. The Failover Clustering feature needs to be installed as clustering components are needed.

(Video) 04. How to configure Storage Spaces on Windows Server 2016 (Step by Step guide)

Will the storage bus cache work with an all flash configuration?

No, this feature will only work when there are two media types, one of which must be HDD. This will not work with RAID, SAN, or all flash systems.

How can the storage bus cache settings be change?

See example below for changing the Provision mode from Shared (default) to Cache. Note that default settings are recommended and any changes should be made before the storage bus cache is enabled.

Set-StorageBusCache -ProvisionMode Cache


What is storage bus cache? ›

Storage bus cache is a read and write caching technology that attempts to speed up transfers through a tiering system that uses faster drives, such as SSD, on the server for the cache.

What is the difference between storage pool and storage spaces? ›

Storage pools — A group of physical disks, which allows you to manage and use the combined disk space of all physical disks in the pool. Storage Spaces — Virtual disks (VDs) created from free disk space in a storage pool. You can configure each Storage Space VD with a specific resiliency layout and storage tiers.

What is the shared cache percent in storage bus cache? ›

Shared cache percentage

The default value is 15% and the field can be set from 5% to 90%. A value over 50% is not recommended when using mirror accelerated parity volumes as there needs to be a balance between the cache and the mirror tier.

How will you manage the storage spaces? ›

Go to the taskbar, type Storage Spaces in the search box, and select Storage Spaces from the list of search results. Select Change settings > Physical drives to see all the drives in your pool. Find the drive you want to remove and select Prepare for removal > Prepare for removal.

What is the purpose of cache storage? ›

A cache's primary purpose is to increase data retrieval performance by reducing the need to access the underlying slower storage layer. Trading off capacity for speed, a cache typically stores a subset of data transiently, in contrast to databases whose data is usually complete and durable.

What are the 5 types of storage? ›

Types of storage devices
  • SSD and flash storage. Flash storage is a solid-state technology that uses flash memory chips for writing and storing data. ...
  • Hybrid storage. ...
  • Cloud storage. ...
  • Hybrid cloud storage. ...
  • Backup software and appliances.

Does cache take up a lot of space? ›

It helps apps load faster by keeping temporary files such as thumbnails, scripts, and video snippets on your phone instead of loading them from the web each time. But cached data can quickly fill up your phone's storage.

What is a good cache ratio? ›

What is a Good Cache Hit Ratio? As a general rule of thumb - a cache hit ratio of 80% and higher is a good result as it means that most of the requests are served from the cache. Anything below 80% on static websites indicates an inefficient caching policy.

What is a good cache size? ›

Disk caches smaller than 10 MB do not generally perform well. Machines serving multiple users usually perform better with a cache of at least 60 to 70 MB. The point at which enlarging the cache further does not really improve performance depends on the factors mentioned previously, and is difficult to predict.

How can I improve my storage performance? ›

Seven tips to improve data storage efficiency
  1. Improve the storage network. ...
  2. Implement server-side flash. ...
  3. Deploy a network cache. ...
  4. Consider a cloud-enabled network cache. ...
  5. Implement SDS with a small flash array. ...
  6. Optimize applications. ...
  7. Buy a new all-flash or hybrid array. ...
  8. In summary.
Aug 3, 2016

What are the 3 most important things about storage areas? ›

When looking for a good storage facility, you need to find one with these qualities. The facility needs to be able to keep out pests, thieves, temperature, and humidity while providing insurance, pickup services, and a wide range of unit sizes.

What are the three basic aspects of storage management? ›

As the computation proceeds, the storage block is disintegrated into smaller elements through allocation, recovery, and reuse.

What happens if you clear storage cache? ›

Your cache is stored on your Computer or Phone in a temporary directory - these files take up a bit of space on your disk, so by clearing your cache you are deleting those temporary files which frees up a bit of space on your device.

What happens when you clear cache in storage? ›

This will delete all user data stored within an app, not just the temporary cache files. The app itself won't be deleted, but it will be reset, meaning you'll need to sign in again and set any preferences.

Where is cache memory located? ›

It is located outside the CPU and is shared by all the cores of a CPU. Its memory size ranges from 1 MB to 8 MB. Although it is slower than L1 and L2 cache, it is faster than Random Access Memory (RAM).

What are the types of memory cache memory? ›

There are two different types of cache memory: primary and secondary. Primary cache memory is found on the CPU itself whereas secondary cache memory is found on a separate chip close to the CPU.

What type of storage is cache? ›

cache memory, also called cache, supplementary memory system that temporarily stores frequently used instructions and data for quicker processing by the central processing unit (CPU) of a computer. The cache augments, and is an extension of, a computer's main memory.

What are the 2 types of caching? ›

Four Major Caching Types and Their Differences
  • Web Caching (Browser/Proxy/Gateway): Browser, Proxy, and Gateway caching work differently but have the same goal: to reduce overall network traffic and latency. ...
  • Data Caching: ...
  • Application/Output Caching: ...
  • Distributed Caching:

What are the two basic storage methods for the storage structure? ›

Two kinds of storage structures are familiar from everyday life: stack and queue.

What is the 5 primary storage? ›

read only memory (ROM) random access memory (RAM) flash memory. cache memory.

What are the 8 units of storage? ›

Units of storage
Megabyte1024 kilobytes
Gigabyte1024 megabytes
Terabyte1024 gigabytes
Petabyte1024 terabytes
3 more rows

Is it OK to delete cache files on Android? ›

Clearing your Android app cache can help fix speed issues and free up storage space. If you need more storage, clear the cache of the apps that take up the most space. Clearing your app cache every few months will help streamline your phone and keep it from getting too full.

Should I delete cache storage? ›

Cache data can slow down your phone's browsing performance since it takes up storage space in your device, so it's good to clear it out regularly.

Is it okay to delete cache memory? ›

Clearing your cache on Android can free up valuable space and resolve issues with your phone's battery, speed, and security. Old cached data can corrupt, causing larger performance problems. If a particular app receives an update, the cached data from a previous version can cause conflict.

Is it OK to delete Windows cache files? ›

So if you clear your browser's cache and temporary internet files regularly, this helps your computer or device run optimally—and doing so can help fix certain problems, like a website loading slowly, or formatting issues on a web page.

What happens if you delete all cache files? ›

What Happens After Clearing Android Cache? After you clear cached files, you'll regain some storage space and the app will continue to work as normal. However, since you erased the data used for optimal performance, some elements (like those mentioned above) will load more slowly the next time you use the app.

What happens when you delete your cache? ›

After you clear cache and cookies: Some settings on sites get deleted. For example, if you were signed in, you'll need to sign in again. If you turn sync on in Chrome, you'll stay signed into the Google Account you're syncing to in order to delete your data across all your devices.

Does deleting cache files do anything? ›

What Will Clearing Cached Data Do? Most devices have some form of cache cleanup. New data comes in, and older information is removed. This system ensures that your device isn't bogged down by so much storage that it can't tackle anything new.


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