What is difference between VDisk and Physical Disk?

Database
RMM
Enthusiast

What is difference between VDisk and Physical Disk?

Hi,

Please can you advise for the below query.

1) What is difference between VDisk and Physical Disk?

Regards,

Rishikesh

5 REPLIES
Enthusiast

Re: What is difference between VDisk and Physical Disk?

hi Rishi,

VDisk is the logical partition of your physical disk.
Physical disk in teradata can be called as RAID array of disks, where your data is stored physically i.e. written to disk.
N/A

Re: What is difference between VDisk and Physical Disk?

Hi,

Can someone explain what is the VDISK. What it actually contains.. 

Enthusiast

Re: What is difference between VDisk and Physical Disk?

Teradata Virtual Storage pools all of the cylinders within a clique's disk space and allocates cylinders from this storage pool to individual AMPs.

Enthusiast

Re: What is difference between VDisk and Physical Disk?

Teradata virtual storage responsibility is:

  • Pooling clique storage and allocating cylinders from the storage pool to individual AMPs
  • Tracking where data is stored on the physical media
  • Maintaining statistics on the frequency of data access and on the performance of physical storage media
  • Migrating frequently used data (“hot data”) to fast disks and data used less frequently (“cold data”) to slower disks.
Teradata Employee

Re: What is difference between VDisk and Physical Disk?

Disk Arrays

A disk array is a matrix of independent but interconnected physical disk storage units. For the Teradata RDBMS, the disks are organized as a Redundant Array of Independent Disks (RAID), as RAID 1 (mirroring) or RAID 5 or RAIDS (parity) technology using RAID Manager. Each array typically consists of from one to four ranks of disks, with up to five disks per rank. 2

RAID Manager uses drive groups. A drive group is a set of drives that have been configured into one or more logical units (LUNs). All the disks in a drive group must be of the same RAID level (1,5 or S). A LUN is a portion of every drive in a drive group. These portions are configured to represent a single UNIX disk. Each LUN is uniquely identified and sliced into one or more UNIX slices.

Pdisks

A pdisk is a slice of LUN that is assigned to an AMP. Each pdisk is uniquely identified and independently addressable.

Virtual Disks (vdisks)

The groups of pdisks assigned to an AMP are collectively identified as a vdisk. Vdisks are used to control the assignment of pdisks to AMPs.