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What Are Basic and Dynamic Disks? Features for Dynamic/Basic Disks


    Basic disks and dynamic disks are 2 types of hard disk configurations most often used with Windows. The former appears along with hard disk while the latter was introduced since Windows 2000. Different disk configurations have different features, but they are related.

    What Is Basic Disk

    Basic disks use partitions (in late versions of Windows OS like Windows 7 and Windows 8 it is also called volume) to manage data, and one partition cannot share and split data with other partitions. On a basic hard disk, we can create 2 styles of partitions, namely MBR style partition and GPT style partition. To crate MBR style partitions, we need to initialize the hard disk to MBR (master boot record). To create GPT style partitions, we should initialize the disk to GPT (GUID partition table). For more information, please see About Partition Style (MBR and GPT) part in Ways to Convert Partition Type, Partition Style, and Disk Type.

    On MBR disks, partitions are called primary partition, extended partition, or logical partition while all partitions on GPT disk are called GPT partitions which function like primary partitions. A MBR based basic disk can have either four primary partitions or three primary and one extended partition, but the extended partition can contain an unlimited number of logical drives. And a GPT based hard disk can hold up to 128 partitions.

    We can add more space to a primary partition or GPT partition by extending it to an adjacent contiguous unallocated space on the same disk or extend a logical drive to free space contained in extended partition, but these partitions should be formatted with NTFS.

    What Is Dynamic Disk

    Dynamic disk uses dynamic volumes to manage data. It is a separate form of volume management that allows one volume to have noncontiguous extents on one or more physical disks. Dynamic disks use a database to track information about all volumes on the disk as well as information about other dynamic disks, and the location of database is determined by partition style of the disk. On MBR partitions, the database is contained in the last 1 megabyte (MB) of the disk while database on GPT partitions is located in a 1MB reserved partition. In addition,  each dynamic disk in a computer saves a copy of the database, so that Windows can repair a damaged database by using the database on other dynamic disks.

    On a dynamic disk, we can create 5 types of dynamic volumes to enhance computer performance, including simple volume, mirrored volume, striped volume, spanned volume, and RAID volume. A simple volume functions like primary partitions on basic disk; a mirrored volume provides fault tolerance by creating a copy of data contained in this volume; a striped volume improves disk input/output performance by distributing I/O requests across disks; a spanned volume combines spaces on 2 hard disks at least to a dynamic volume; A RAID-5 volume stripes data and parity across three or more disks. For more information about these volumes, please see Dynamic Disk.

    In Windows snap-in Disk Management utility, we are only allowed to extend simple volumes and spanned volumes except for the system and boot one or extend a mirrored volume after breaking the mirror. However, with a third party partitioning program we can extend any types of dynamic volumes.

    Relationship Between Basic Disk and Dynamic Disk

    A basic disk can be converted to dynamic disk without any data loss in Disk Management. Detailed steps are: right click the basic disk, choose “Convert to Dynamic Disk” from the popup menu, click “OK” and tap on “Convert” to get the window below:

    What are basic and dynamic disks 1

    This message shows we cannot start installed operating systems from any volume on this disk except the current boot one. That is to say all Windows OS except the current running one will be unbootable. Therefore, users who are dual or multi booting Windows on one disk had better not convert the basic disk to dynamic disk if they want to run all Windows well. 

    Moreover, when converting basic disk to dynamic, users may be troubled by the error:

    What are basic and dynamic disks 2

    This will appear if there is no enough free space that is not partitioned at the end of the disk to create the database for the dynamic disk. To fix the error, we need to shrink the last partition to create such a space via the feature “Shrink Volume”.

    However, once a disk has been converted to dynamic disk, you will be unable to convert it to basic disk in both Disk Management and Diskpart before deleting all existing dynamic volumes. But fortunately, there is third party partitioning tool which makes it possible to restore a dynamic disk to basic without deleting any information. For detailed steps, please see Convert Dynamic Disk to Basic Disk.