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Windows Server 2012 and Windows 8 Feature Storage Spaces

storage spaces file services

Windows Server 2012 and Windows 8 Feature Storage Spaces

Imagine the benefits of centralized storage with the ease it provides a protocol for file sharing. Redundancy, flexibility, performance, and all you see is a shared directory. Dream or reality?

Centralized data storage, which allows for easy management of data redundancy, flexibility and above all, adequate performance, the desire is by almost every serious company. In doing so, even it does not matter whether it is a company with five or maybe 500 employees, the company is engaged in the development of software, or something else. For centralized storage of data will need to be a proper system, and most often it is a SAN (Storage Area Network).

storage area network san what it is

Take for example a company that specializes in software development and that, typically, has a multitude of virtual servers for development and testing. A large number of virtual servers requires a number of physical servers to move them, but requires a central storage system in order to better manage natural resources. If we connect the physical servers in the cluster, the virtual servers can be easily moved between physical without undue copying virtual disks, freeing up some servers to run demanding tests almost immediately. Of course, the above scenario is not possible without a central storage system that is usually expensive and time consuming to adjust, but the advent of Microsoft Windows Server 2012 that could change.

SAN storage area network

New Functionality in Windows Server 2012 and Windows 8 – Storage Spaces

The latest Microsoft operating system Windows Server 2012 and Windows 8 brings a host of new features, among which, within a storage subsystem, hiding one very interesting technology called Storage Spaces. It is a technology that enables storage virtualization by separating the logical from the physical level in a way that the physical resources or disks created groups that storage pools, each of which can then create a virtual first and then logical drives for storage. Storage Spaces are all about provisioning storage based on a pooled model. By using Storage Spaces, you have the ability to organize storage in a different way. You may combine various types of storage for a single use.  The primary advantage of Storage Spaces is that you no longer need to manage single disks, but you can instead manage them as one unit.

The idea is not new, has been implemented in many commercial storage systems with the restriction that it is possible to combine only the components of the same manufacturer – a well-known vendor lock-in.

On the other hand, you may combine various types of storage for a single use. Microsoft allows the storage pool is formed by using disks of any manufacturer, and the disks can be used SAS or SATA, and even a USB interface and can be mechanically or SSD’s. Here it should be that the entire pool disks adjust the weakest component, so it is advisable to use the same pool disks similar characteristics.

It is also possible to use SAS JBOD  (Serial Attached SCSI Just-a-Bunch-Of-Disks) devices directly connected to the server. If the drives connected to the RAID controller, all RAID functionality must be excluded because Storage Spaces is not compatible with systems that bring an additional level of abstraction when accessing disks.

Storage Spaces is the role in Windows Server 2012 and is available immediately after installing the system, and adding the role, and is supported in full (GUI) and the basic (core) version. Managing Storage Spaces is possible via the Server Manager, under File and Storage Services if you use the GUI or via PowerShell commands.

storage space console attach disk manual

Storage Spaces – Limitations and Benefits

Some of the benefits of Storage Spaces include the ability to:

  •  Obtain and manage easily reliable and scalable storage with reduced cost
  • Use PowerShell to manage Storage Spaces for Windows 8 clients or Windows Server 2012
  • Aggregate individual drives into storage pools, managed as a single entity
  • Utilize inexpensive simple storage with or without external storage
  • Provision storage as needed from pools of storage you’ve created
  • Grow storage pools on demand
  • Designate specific drives as hot spares
  • Delegation of administration by specific pool
  • Use diverse types of storage in the same pool: SATA, SAS, SCSI,USB.
  • Use existing tools for backup/restore, as well as VSS for snapshots
  • Automatic repair for pools containing hot spares with  storage capacity to cover what was lost
  • Management can be local, through MMC , remote, or PowerShell.

It is also possible to use Storage Spaces with Failover Clusters. However, use with clusters has a limitation to Serial Attached SCSI (SAS) as a storage medium. Failover clustering does not support  Storage Spaces using other storage technologies. The performance of this technology depends on the performance capabilities of the storage that are choosed  to pool together.

With this  in mind, below are some limitations:

  • Not supported on boot, system, or CSV volumes
  • Drives must be 10GB or larger
  • Add only un-formatted/un-partitioned drives
  • When you introduce a drive into a storage pool, the contents of the drive being added will be lost.
  • A simple storage pool must consist of at least one drive
  • Three drive minimum for using Parity
  •  A mirrored pool must have at least 2 drives. For 3-way mirroring there is an obvious need for more
  • Fibre-channel and iSCSI are not supported
  • All drives in a pool must use the same sector size
  • Storage must be storport.sys compatible
  • Virtual disks to be used with a failover cluster that emanate from a storage pool must use the NTFS file system. ReFS or third-party file systems may be used for other purposes

storage spaces storage pool

Storage Spaces Features and how does Storage Spaces work?

To configure  Storage Spaces, you must consider the features before you implement virtual disks. Features are:

- Storage Layout - Defines the number of disks from the storage pol that are allocated. Options are:

  1.              Simple spaces that has data striping, but no redundancy.
  2.             Two-way and three-way mirror spaces maintain two or three copies  of data they host
  3.             Parity space resembles a simple spaces.

- Data sector size - A storage pool’s sector size is set the moment it is created. If the list of drives being used contains only 512 and 512e drives, the pool is defaulted to 512e.

- Cluster Disk requirement – This defines how the drive is allocated to the pool, Options are:

  1. Data-store - This is the default allocation when any drive is added to a pool.
  2. Manual  -  Administrators can choose to specify manual as the usage type for drives added to a pool.
  3. Hot-Spare - Drives added as “Hot-Spares” to a pool are reserve drives that are not used in the creation of storage space.

-  Provisioning schemes - You can provision a virtual disk by using two schemes:

  1. Thin Provisioning space- It is a mechanism that enables storage to be easily allocated on a just-enough and just-in-time basis.
  2. Fixed ( Thick ) Provisioning space, the difference is that the storage capacity is allocated up front, at the time that the space is created.

The volumes that you create within a storage pool are basically virtual disks, thay are located on the storage pool that you may then partition, format, and assign drive letters. Storage Spaces maintains the health of these drives and any selected  redundancy. Storage Spaces stores metadata on every volume within the storage pool that defines how data will be stored within the pool.

If you  look at the device stack for a disk on occasion within a debugger, you would notice that access to a virtual disk that is part of a storage pool also use the SpacePort.sys device driver.  This is a necessary driver to provide the Storage Spaces functionality within Windows OS. You may find this driver within Device Manager listed under Storage controllers as Microsoft Storage Spaces Controller. Furthermore , when you look at an some disk device with the System Information tool under System Tools, you will notice the model as Microsoft Storage Space Device.

file and storage services storage pools

Typical provisioning for a volume that uses all available space is named  as thick provisioning. It is possible to use thin provisioning with Storage Spaces which allows larger allocation of virtual drives than available space. With thin provisioning, blocks are only used from the pool as used by virtual disks. With thick provisioning, virtual disks will use and map all available space from the storage pool. However, be aware that when using thin provisioning, important is to monitor disk usage closely to avoid the reality of an overcommitted pool. You may still add additional space to the pool as needed by adding additional disk drives.  Also note that thin provisioning is not supported with failover clusters.