How the disk subsystem works in OpenNebula

Recently, I have been receiving quite a lot of questions regarding the organization of a storefront in OpenNebula. In view of its specificity, it has already three different types of storage: images , system and files . Let's see why each of them is needed and how to use them to plan data placement most effectively.

This post is a partial transcript of my talk about OpenNebula on HighLoad ++ 2019 with emphasis on the disk component.

So according to the story:

OpenNebula has three types of stories: images , system and files .

• images datastore — , .
  : persistent non-persistent — system datastore:

  
  
  • non-persistent images system datastore, linstor_un : copy snapshot , .
  • persistent images system datastore
  
  

  ( " " , persistent- images-datastore )

  
  

• system-datastore — .
  system-datastore . , persistent images , non-persistent .

  
  

:

persistent- images-, , system- , , . ( system-datastore , images-datastores ).

system-datastore - ( : SSD, : 2), .. .

persistent- images-datastores, :

• — SSD : 3
• — HDD : 2

., images-datastore

files-datastore?

• files datastore — -, runtime- .

- , .

files-datastore , ssh, frontend compute- .

, linstor_un ?

:

• images:

  
  

  NAME="linstor-images"
  TYPE="IMAGE_DS"
  STORAGE_POOL="data"
  AUTO_PLACE="2"
  BRIDGE_LIST="node1 node2 node3"
  DISK_TYPE="BLOCK"
  DS_MAD="linstor_un"
  TM_MAD="linstor_un"

  
  

• system:

  
  

  NAME="linstor-system"
  TYPE="SYSTEM_DS"
  STORAGE_POOL="data"
  AUTO_PLACE="2"
  CLONE_MODE="snapshot"
  CHECKPOINT_AUTO_PLACE="1"
  BRIDGE_LIST="node1 node2 node3"
  TM_MAD="linstor_un"

  
  

linstor-images, non-persistent, .. :

images- ( AUTO_PLACE="2" linstor-images)

system-datastore CLONE_MODE=snapshot, . .

, , CLONE_MODE=copy, system-datastore - images-datastore .
AUTO_PLACE system-datastore.

- instantiate as persistent OpenNebula, images-datastore persistent- .

diskless-:

OpenNebula , , diskless-. , , , , , , :

, diskless- .. .

OpenNebula.

, :

!