M2 - Lesson 2: Managing volumes in Windows Server
Volume Types
Simple volumes: A simple volume is a volume that uses free space from a single disk. It can be a single region on a disk, or consist of multiple, concatenated regions. You can extend a simple volume within the same disk or extend it to additional disks. If you extend a simple volume across multiple disks, it becomes a spanned volume.
Spanned volumes: A spanned volume is a volume that is created from the free disk space from multiple disks that are linked together. You can extend a spanned volume onto a maximum of 32 disks. You cannot mirror a spanned volume, and they are not fault-tolerant. Therefore, if you lose one disk, you will lose the entire spanned volume.
Striped volumes: A striped volume is a volume that has data that is spread across two or more physical disks. The data on this type of volume is allocated alternately and evenly to each of the physical disks. A striped volume cannot be mirrored or extended, and is not fault tolerant. This means that the loss of one disk causes the immediate loss of all the data. Striping also is known as RAID-0.
Mirrored volumes: A mirrored volume is a fault-tolerant volume that has all data duplicated onto two physical disks. All of the data on one volume is copied to another disk to provide data redundancy. If one of the disks fails, you can access the data from the remaining disk. However, you cannot extend a mirrored volume. Mirroring also is known as RAID-1.
RAID-5 volumes: A RAID-5 volume is a fault-tolerant volume that has data striped across a minimum of three or more disks. Parity also is striped across the disk array. If a physical disk fails, you can recreate the portion of the RAID-5 volume that was on that failed disk by using the remaining data and the parity. You cannot mirror or extend a RAID-5 volume.
Types of RAID
Tools to create & manage volumes
Server Manager
Disk Management
Diskpart.exe
PowerShell
Extending & Shrinking a volume
You can resize volumes with Server 2016
Considerations when resizing a disk
You only have the ability to shrink or extend NTFS volumes. You cannot resize FAT, FAT32, or exFAT volumes.
You can only extend ReFS volumes; you cannot shrink them.
You can extend a volume by using free space both on the same disk and on other disks.
If bad clusters exist on the volume, you cannot shrink it.
When you want to shrink a volume, immovable files such as page files are not relocated. This means that you cannot reclaim space beyond the location where these files are on the volume.
When you extend a volume with other disks, you create a dynamic disk with a spanned volume. Remember though, in a spanned volume, if one disk fails, all data on the volume is lost. In addition, a spanned volume cannot contain boot or system partitions. Therefore, you cannot extend your boot partitions by using another disk.
What is RAID?
Fault Tolerance
Disk mirroring: With disk mirroring, all of the information that is written to one disk is also written to another disk. If one of the disks fails, the other disk is still available.
Parity information: Parity information is used in the event of a disk failure to calculate the information that was stored on a disk. If you use this option, the server or RAID controller calculates the parity information for each block of data that is written to the disks, and then stores this information on another disk or across multiple disks. If one of the disks in the RAID array fails, the server can use the data that is still available on the functional disks along with the parity information to recreate the data that was stored on the failed disk.
Combines multiple disks into a single logical unit to provide fault tolerance and performance benefits
Hardware vs. Software RAID
Hardware
Hardware RAID requires disk controllers that are RAID-capable. Most disk controllers shipped with new servers have this functionality.
To configure hardware RAID, you need to access the disk controller management program. Normally, you can access this during the server boot process or by using a webpage that runs management software.
Software
Implementing disk mirroring with software RAID for a disk containing the system and boot volume can require additional configuration when a disk fails. Because the RAID configuration is managed by the operating system, you must configure one of the disks in the mirror as the boot disk. If that disk fails, you might need to modify the boot configuration for the server to start the server.
In older servers, you might obtain better performance with software RAID when using parity, because the server processor can calculate parity more quickly than the disk controller can.
RAID 0
Single disk failure results in loss of all data
RAID 1
RAID 5
RAID 1+0
Good performance
Can tolerate the failure of two or more disks provided that both disks in a mirror do not fail
Description: Striped set with distributed parity Data is written in blocks to each disk, with parity spread across all disks
High read and write performance
All space on the disk is available
Can only use the amount of space that is on the smallest disk
Can tolerate a single disk failure
Description: Mirrored set without parity or striping Data is written to both disks simultaneously
Description: Striped set without parity or mirroring Data is written sequentially to each disk
Good read performance, poor write performance
Can tolerate a single disk failure
Uses the equivalent of one disk for parity
Very good read and write performance
Only half the disk space is available due to mirroring
Description: Mirrored set in a stripe set Several drives are mirrored to a second set of drives, and then one drive from each mirror is striped