When creating a storage space how many disks are needed when setting up parity for resiliency settings in a storage pool?

Storage Spaces provide some level of fault tolerance (resiliency). If one disk in the pool fails no data is lost and a failed disk can be easily replaced. To a certain extent this function is identical to RAID (redundant array of independent disks) Level 1 (“mirror”) and Level 5 (striping with distributed parity). But unlike RAID Storage Spaces allow us to combine disks of any type and size. However, if you are already using a hardware or software RAID, then switching to Storage Spaces makes no sense since you will not get any benefits (data protection or performance).

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• Which storage space resiliency type offers no data protection when a drive fails?
• What is Resiliency type?
• When creating a storage space how many disks are needed when setting up parity for resiliency settings in a storage pool?
• Which tool in Windows should you use to manage storage spaces?

Storage Spaces can be used to store of files' history and system image backups, temporary (configured as simple) or really important files (configured as 2-way mirror or parity). The function works with NTFS-formatted drives and allows you to set special permissions for files and folders or enable content encryption (BitLocker is also supported). Windows 8/8.1/10 recognizes relatively new ReFS file system so this format can also be selected when creating Storage Spaces.

Unlike traditional drives Storage Spaces do not need to be defragmented. There is also no need to use disk check on them. In case of any problems Windows immediately notify you. If one of the physical disks becomes damaged just disconnect it, restore and add it to the pool again.

If you combine disks with similar performance (two identical internal hard drives) the overall speed of reading speed increases significantly. While the write speed slightly drops. When combining internal and external disks the read & write speeds are slightly higher than the slowest disk in the storage pool.

Although Windows 8, 8.1 and 10 allow you to mix disks of different sizes it is recommended to use disks of the same size to avoid of disk space waste. For instance, by connecting one 300 Gb disk and one 750 Gb disk in a double-sided mirror you get 525 Gb disk space (virtual disk). The calculation is the following: (300 + 750) / 2 - to ensure resiliency only half of the total disk space is available when using a 2-way mirror. The remaining space is used for data backup. But since mirroring implies that all disks in the storage pool contain the same data the actual usable space is limited to 300 Gb (the smallest physical disk in the pool simply cannot store more data). This means that an additional 450 Gb on a 750 Gb disk is not used and we are not able to store more than 300 Gb unless you add the disk(s) with a capacity that is sufficient to provide resiliency in case of failure of the largest disk. Of course you can remove small disks and replace them with more capacious ones later - but only one at a time to avoid data loss.

Storage Spaces can be easily connected (in any order) to any other computer with Windows 8/8.1/10 but earlier versions of Windows do not support Storage Spaces - for them, as we said, this is an unrecognized partition.

And finally it is important to note that the system disk (on which the operating system is installed) cannot be added to Storage Spaces logic.

1. Column
2. TECHNOLOGY Q&A

By J. Carlton Collins, CPA

Q. My computer has three 1 TB hard drives, but I have 1.5 TBs of data that won't fit on a single drive. In this case, should I replace one of my drives with a larger hard drive or just purchase a new computer?

A. I assume your goal is to organize all your data files on a single drive letter, such as the D drive, for example. If so, you don't need to purchase a new hard drive or a new computer to achieve this goal. You can create a single drive letter for storing your data files across all of your hard drives as follows. Right-click the Windows 10 Menu button and select System, Storage, Manage Storage Spaces, Create a new pool and storage space. Windows 10 will search your computer for all available hard drives. These drives can be internal or external hard drives, or even solid-state drives. You can also combine a variety of drive types, such as USB, SATA, and SAS drives, to accomplish this feat. For example, if you have three drives of 1 TB each, you could create a 3 TB virtual drive, officially referred to as a Storage Pool, using these three 1 TB hard drives. As if that weren't nifty enough, you could even create a 4 TB or a 5 TB virtual drive from your three 1 TB hard drives, and as the virtual drive begins to fill up, you will be notified to install more hard drives to increase your available hard disk space. To create your new storage space on a ­Windows 10 computer, continue by providing a Name, Drive letter, File system, Resiliencytype, Size, and then click the Create storage space button at the bottom of the screen, as pictured below.

Although the ability to group different drive technologies of differing sizes is a nice feature, it's not the main reason CPAs typically use the Storage Space tool. Primarily, CPAs create virtual storage spaces so they can then configure different types of data protection (referred to as "resiliency") on their hard drives, as follows:

1. Simple resiliency: While this option will combine your hard drives into a single virtual drive, it does nothing to protect the data. It merely writes one copy of the data across all your hard drives, and if a single drive fails, you will lose at least some of your data.
2. Two-way mirroringresiliency: This option will write two copies of the data across your physical hard drives in such a way that it protects the data from a single drive failure. Two-way mirroring requires at least two physical drives. If one drive fails, the redundant files on your remaining hard drives will allow you to recover all the data files.
3. Three-way mirroring resiliency: Similar to two-way mirroring, this option writes three copies of the data across your physical hard drives, which will help to protect the data from two simultaneous drive failures. Three-way mirroring requires at least three drives.
4. Parity resiliency: Similar to the standard RAID 5 technology typically found in network servers today, this option doesn't make duplicate or triplicate copies of your files as discussed above, but it does write parity information across your physical hard drives, which allows Windows 10 to reconstruct the data files (using the parity bit information) so you can recover the data from a single drive failure. As a simple example, if the bits 0, 1, 0, 1 are saved on two hard drives, then a checksum parity bit (2 in this example because 0+1+0+1=2) is saved on the third drive. Thereafter, if one bit is lost, the check bit can be used with the three remaining bits to recover the missing bit. (For example, if one drive fails and the bits 0, 1, 0, ? must add to 2, then the computer can calculate that the missing bit must be a 1.) This option requires a least three drives.

If your goal is merely to create one virtual drive from multiple hard drives, then simple resiliency may be the best option. However, if your computer files are mission critical (which means you don't even have time to restore backups should the need arise), then you should select one of the other resiliency options. In this case I usually recommend two-way mirroring. While three-way mirroring offers greater protection, its downfall is that it uses more storage space. The parity resiliency option uses the least amount of storage space, but some CPAs reject this option because the data reconstruction process sounds daunting. In fact, the reconstruction process is almost exactly like uncompressing (or extracting) a set of compressed data files.

It is important to note that in no event do these data protection options negate the need for regular or continuous backup procedures, because these resiliency measures do not prevent data loss in the event of fire, theft, or malware.

About the author

J. Carlton Collins () is a technology consultant, a conference presenter, and a JofA contributing editor.

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Which storage space resiliency type offers no data protection when a drive fails?

Storage Spaces provides you with four Resiliency Types: Simple (no resiliency) writes one copy of your data and doesn't protect you from drive failures. A simple storage space requires at least two drives.

What is Resiliency type?

Types of Resilience: Psychological, Emotional, Physical, and Community. The word resilience is often used on its own to represent overall adaptability and coping, but it can be broken down into categories or types: Psychological resilience. Emotional resilience.

When creating a storage space how many disks are needed when setting up parity for resiliency settings in a storage pool?

The Parity resiliency type writes across all disks with redundancy information. At least three disks are required in a storage pool to protect against the failure of one drive.

Which tool in Windows should you use to manage storage spaces?

Disk Management is a system utility in Windows that enables you to perform advanced storage tasks.

How many drives are needed for a parity resiliency type?

What is the minimum number of disks needed for parity storage layout?

What is the minimum number of disks necessary for creating a storage pool using the three

Which types of resiliency requires at least three disks?