reg:// Snap shot Vs Sanp Clone

[sandilyan]

Hi,

I have a doubt in Snapshot and Snapclone in SAN.

1) What is Snapshot ?
2) What are types Snapshot?
3) What is a snapclone ?
4) what are types of snapclone ?
5) what is difference between snapshot and snapclone ?


Thanks
Sandilyan S

[Víctor Cespón]

Example, in an EVA:

Snapshot:

Only copies the changes made to the vdisk since the moment the snapshot is created.

2 types:
- Demand allocated: it grabs space as needed
- Fully allocated: it reserves a space the same size of the original disk

Snapshots depend on the original disk and must be on the same disk group. Part of the accesses to the snapshot go to the original disk since they have a part in common.

Snapclone:
This is a full copy of the source vdisk. After the copy is finished it becomes an indepent vdisk. It can be created on a different disk group.

This way the traffic to the snapclone is independent of the traffic to the source vdisk.

[sandilyan]

Hi all,

Thank u for help !!!!!!!!!!!!!

What is the difference between snapclone and Fully allocated snapshot ?


Thanks
Sandilyan S

[Víctor Cespón]

The snapclone is a copy of all the data on the vdisk, whether it has been changed or not, and when finished it becomes a vdisk independent of the original.

A fully allocated snapshot contains only the changes done since it's creation. You just create it with a size big enough to contain a copy of all sectors on the original disk.
A snapshot is always associated to the source vdisk, and if you read on a sector that has not been changed, it's read from the source vdisk. So part of the traffic to the snapshot goes to the source vdisk.