mastering openstack - episode 08 - storage decisions

Presentation By:

Roozbeh Shafiee

Autumn 2015

IRAN OpenStack Users Group

MASTERINGOPENSTACK

(Episode 08)

Storage Decisions

IRAN Community| OpenStack.ir

Agenda:

● Storage Types

● Storage Specifications

● Iran OpenStack Community

OpenStack Storage Decisions


Storage Types



Storage Types

Storage is found in many parts of the OpenStack stack, and the differing types can

cause confusion to even experienced cloud engineers.

This section focuses on persistent storage options you can configure with your

cloud. It’s important to understand the distinction between ephemeral storage

and persistent storage.



Ephemeral Storage

If you deploy only the OpenStack Compute Service (nova), your users do not have

access to any form of persistent storage by default.

The disks associated with VMs are “ephemeral,” meaning that they effectively

disappear when a virtual machine is terminated.



Persistent Storage

Persistent storage means that the storage resource outlives any other resource

and is always available, regardless of the state of a running instance.

Today, OpenStack clouds explicitly support two types of persistent storage:

● Object Storage

● Block Storage



Storage Specifications



Ephemeral Storage

● Used to: Run operating system and scratch space

● Accessed through: A file system (XFS, EXT4, BTRFS)

● Accessible from: Within a VM

● Managed by: OpenStack Compute (nova)

● Persists until: VM is terminated

● Sizing determined by: Administrator configuration of size settings

● Example of typical usage: 10 GB first disk, 30 GB second disk



Block Storage

● Used to: Add additional persistent storage to a virtual machine (VM)

● Accessed through: A block device that can be partitioned, formatted & mounted

● Accessible from: Within a VM

● Managed by: OpenStack Block Storage (cinder)

● Persists until: Deleted by user

● Sizing determined by: User specification in initial request

● Example of typical usage: 1 TB Disk



Object Storage

● Used to: Store data, including VM images

● Accessed through: The REST API

● Accessible from: Anywhere

● Managed by: OpenStack Object Storage (swift)

● Persists until: Deleted by user

● Sizing determined by: Amount of available physical storage

● Example of typical usage: 10s of TBs of dataset storage



File-level Storage (for Live Migration)

With file-level storage, users access stored data using the operating system’s

file system interface. Most users, if they have used a network storage solution

before, have encountered this form of networked storage. In the Unix world, the

most common form of this is NFS. In the Windows world, the most common form

is called CIFS (previously, SMB).



File-level Storage (for Live Migration)

OpenStack clouds do not present file-level storage to end users. However, it is

important to consider file-level storage for storing instances under

/var/lib/nova/instances

when designing your cloud, since you must have a shared file system if you want

to support live migration.


Roozbeh ShafieeIran OpenStack Community Manager

[email protected]

OpenStack.ir

Thank You

We need to work together to build a better community

mailto:[email protected]

mastering openstack - episode 08 - storage decisions

Technology