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Storage Spaces Overview

Published: February 29, 2012

Updated: April 9, 2014

Applies To: Windows 8, Windows 8.1, Windows Server 2012, Windows Server 2012 R2



This topic discusses Storage Spaces, a technology in Windows and Windows Server that enables you to virtualize storage by grouping industry-standard disks into storage pools, and then create virtual disks called storage spaces from the available capacity in the storage pools. This topic provides an overview of the technology and new Storage Spaces functionality in Windows Server 2012 R2.

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Storage Spaces enables cost-effective, highly available, scalable, and flexible storage solutions for business-critical (virtual or physical) deployments. Storage Spaces delivers sophisticated storage virtualization capabilities, which empower customers to use industry-standard storage for single computer and scalable multi-node deployments. It is appropriate for a wide range of customers, including enterprise and cloud hosting companies, which use Windows Server for highly available storage that can cost-effectively grow with demand.

With Storage Spaces the Windows storage stack has been fundamentally enhanced to incorporate two new abstractions:

  • Storage pools. A collection of physical disks that enable you to aggregate disks, expand capacity in a flexible manner, and delegate administration.

  • Storage spaces. Virtual disks created from free space in a storage pool. Storage spaces have such attributes as resiliency level, storage tiers, fixed provisioning, and precise administrative control.

Storage Spaces is manageable through the Windows Storage Management API in Windows Management Instrumentation (WMI) and Windows PowerShell, and through the File and Storage Services role in Server Manager. Storage Spaces is completely integrated with failover clustering for high availability, and it is integrated with CSV for scale-out deployments.

Storage Spaces includes the following features:

  • Storage pools. Storage pools are the fundamental building blocks for Storage Spaces. Storage administrators are already familiar with this concept, obviating the need to learn a new model. They can flexibly create storage pools based on the needs of the deployment. For example, given a set of physical disks, an administrator can create one pool (by using all the available physical disks) or multiple pools (by dividing the physical disks as required). Furthermore, to maximize the value from storage hardware, the administrator can combine hard disks and solid-state drives (SSDs) in the same pool, using storage tiers to move frequently accessed portions of files to SSD storage, and using write-back caches to buffer small random writes to SSD storage. Pools can be expanded dynamically by simply adding additional drives, thereby seamlessly scaling to cope with unceasing data growth.

  • Resilient storage. Storage Spaces provides three storage layouts (also known as resiliency types):

    • Mirror. Data is duplicated on two or three physical disks, increasing reliability, but reducing capacity. This storage layout requires at least two disks to protect you from a single disk failure, or at least five disks to protect you from two simultaneous disk failures.

    • Parity. Data and parity information are striped across physical disks, increasing reliability, but somewhat reducing capacity. This storage layout requires at least three disks to protect you from a single disk failure and at least seven disks to protect you from two disk failures.

    • Simple (no resiliency). Data is striped across physical disks, maximizing capacity and increasing throughput, but decreasing reliability. This storage layout requires at least one disk and does not protect you from a disk failure.

    Additionally, Storage Spaces can automatically rebuild mirror and parity spaces in which a disk fails by using dedicated disks that are reserved for replacing failed disks (hot spares), or more rapidly by using spare capacity on other drives in the pool. Storage Spaces also includes background scrubbing and intelligent error correction to allow continuous service availability despite storage component failures. In the event of a power failure or cluster failover, the integrity of data is preserved so that recovery happens quickly and does not result in data loss.

  • Continuous availability. Storage Spaces is fully integrated with failover clustering, which allows it to deliver continuously available service deployments. One or more pools can be clustered across multiple nodes within a single cluster. Storage spaces are accessed by one node, and the storage will seamlessly fail over to a different node when necessary (in response to failure conditions or due to load balancing). Integration with CSVs permits scale-out access to data.

  • Storage tiers. Storage Spaces in Windows Server 2012 R2 combines the best attributes of SSDs and hard disk drives (HDDs) by enabling the creation of virtual disks comprised of two tiers of storage – an SSD tier for frequently accessed data, and a HDD tier for less-frequently accessed data. Storage Spaces transparently moves data at a sub-file level between the two tiers based on how frequently data is accessed. As a result, storage tiers can dramatically increase performance for the most used (“hot”) data by moving it to SSD storage, without sacrificing the ability to store large quantities of data on inexpensive HDDs.

  • Write-back cache. Storage Spaces in Windows Server 2012 R2 supports creating a write-back cache that uses a small amount of space on existing SSDs in the pool to buffer small random writes. Random writes, which often dominate common enterprise workloads, are directed to SSDs and later are written to HDDs.

  • Operational simplicity. The Windows Storage Management API, WMI, and Windows PowerShell permit full scripting and remote management. Storage Spaces can also be easily managed through the File and Storage Services role in Server Manager. Storage Spaces also provides notifications when the amount of available capacity in a storage pool hits a configurable threshold.

  • Multitenancy. Administration of storage pools can be controlled through access control lists (ACLs) and delegated on a per-pool basis, thereby supporting hosting scenarios that require tenant isolation. Storage Spaces follows the familiar Windows security model; therefore, it can be fully integrated with Active Directory Domain Services.

The following table describes some of the major changes in Storage Spaces. For more detailed information, see What's New in Storage Spaces in Windows Server 2012 R2.

 

Feature/functionality New or updated? Description

Storage tiers

New

Automatically moves frequently accessed data to faster (SSD) storage and infrequently accessed data to slower (HDD) storage.

Write-back cache

New

Buffers small random writes to SSD storage, reducing the latency of writes.

Parity space support for failover clusters

New

Enables you to create parity spaces on failover clusters.

Dual parity

New

Stores two copies of the parity information on a parity space, helping protect you from two simultaneous disk failures while optimizing for storage efficiency.

Automatically rebuild storage spaces from storage pool free space

New

Greatly decreases how long it takes to rebuild a storage space after a disk failure by using spare capacity in the pool instead of a single hot spare.

Storage Spaces has the following requirements:

  • Windows Server 2012 R2, Windows Server 2012, Windows 8.1, or Windows 8

  • Serial ATA (SATA) or Serial Attached SCSI (SAS) connected disks, optionally in a just-a-bunch-of-disks (JBOD) enclosure

    RAID adapters, if used, must have all RAID functionality disabled and must not obscure any attached devices, including enclosure services provided by an attached JBOD.

    noteNote
    Consumers can use USB drives with Storage Spaces, though USB 3 drives are recommended to ensure a high level of performance. USB 2 drives will decrease performance – a single USB 2 hard drive can saturate the bandwidth available on the shared USB bus, limiting performance when multiple drives are attached to the same USB 2 controller. When using USB 2 drives, plug them directly into different USB controllers on your computer, do not use USB hubs, and add USB 2 drives to a separate storage pool used only for storage spaces that do not require a high level of performance.

  • For shared-storage deployments on failover clusters:

    • Two or more servers running Windows Server 2012 R2 or Windows Server 2012

    • Requirements as specified for failover clustering and Cluster Shared Volumes (CSV)

    • SAS connected JBODs that comply with Windows Certification requirements

      For a list of certified JBODs, see the Windows Server Catalog.

    • Identical SAS HBAs that are certified for use with Storage Spaces

      These HBAs are connected to all JBOD enclosures in the file server cluster, and can’t have built-in RAID functionality.

For information about using Storage Spaces to host virtual machines for large scale Hyper-V workloads, see Provide cost-effective storage for Hyper-V workloads by using Windows Server.

For additional related information, see the following resources.

 

Content type References

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