VMware Virtual Machine disks

When you create a disk, you do two things: allocate space, place zeros

1, thick provision delay 0:

The default creation format, when the disk is created, allocates space directly from the disk, but retains data on the disk without zeroing. So when there is an I/O operation, only the zero operation is required.

Good disk performance, short time, suitable for pool-mode virtual desktops

2, thick provision 0 (thick):

Create a cluster-capable disk. When you create a disk, you allocate space directly from the disk, and the disk retains data zero. Therefore, there is no need to wait for direct execution when there is an I/O operation.

Disk performance is the best, long time, suitable for running a heavy application business of virtual machines

3. Thin provisioning (thin):

When the disk is created, the amount of space occupied by the disk is calculated based on the actual usage, that is, the number of points, the space is not allocated in advance, the disk retains data pail zero, and the maximum size of the partition disk.

So when there is an I/O operation, space must be allocated before the space is zeroed to perform I/O operations. Disk performance degrades when there are frequent I/O operations

Disk performance is good when I/O is infrequent,and disk performance is poor when I/O is frequent. Short time, suitable for business application virtual machines with infrequent disk I/O

For example, 1 500GB virtual disks, 100GB used, and 400GB unused space. Thin format vmdk file size is 100GB, Zeroedthick and Eagerzeroedthick format vmdk file size is 500GB, Only the Eagerzeroedthick 400GB unused space has been initialized, all filled in 0, and Zeroedthick that 400GB unused space has not been initialized.

Ref:

http://liuxiaoqiang888.blog.51cto.com/7598464/1893431

http://blog.csdn.net/warmsunshine7/article/details/51007370

Todo

Sparse, Stream optimized,

Thin & Trick

IDE & SCSI

Spass, flat, stream-optimized

VMware Virtual Machine disks