Object Storage is today the standard to build scale-out storage. But due to technical hurdles it is impossible to run Virtual Machines directly from an Object Store. Open vStorage is the layer between the hypervisor and Object Store and turns the Object Store into a high performance, distributed, VM-centric storage platform.
2. The Rise of Object Storage
Source: http://blog.oxygencloud.com/2013/09/16/after-10-years-object-storage-investment-continues-and-begins-to-bear-
significant-fruit/
3. Object Storage
• Amazon Simple Storage Service (S3) started the Object Store
momentum
• ... but new players are taking over:
– Scality
– Ceph
– Swiftstack
– Amplidata
– DataDirect Networks
– ...
• Used to store files but not as primary storage for Virtual Machines
4. Object Storage Benefits
• Build scale-out storage by adding more servers
• High reliability by duplicating content across nodes
• Easy to manage (no need to know about RAID or volumes)
• Standard API as all solutions support S3 API, no vendor lock-in
• Cost-effictive: mix SSDs (small but fast) and SATA (slow but large)
5. Object Storage <> Hypervisor
• Object Storage
– Objects
– Buckets
– S3 API
• Hypervisor
– Files
– Folders
– Volumes
– Block level storage
What is needed is a technology whereby Virtual Machines can use
Object Stores instead of a SAN and get the benefits of the low cost
and scale-out capabilities of Object Stores
6. Object Storage Challenges
• The issues to use Object Storage as VM Storage:
– Eventual consistency (the CAP Theorem)
– Latency & performance
• VMs require low latency and high performance
• Object Stores are developed to contain lots of data
(large disks and low performance)
• Additional latency as Object Store is on the Local LAN instead of
attached to the server
– Different Management Paradigms
• Object Stores understand Objects <> Hypervisors understand VMs
7. Distributed File System?
• Distributed File Systems such as GlusterFS and Ceph are not an
answer:
– The CAP Theorem also applies to these (consistency <> performance)
– They were not designed for VMs (VM Snapshots?, cloning?)
• Even new File Systems (copy-on-write) can’t give an answer
None of the File Systems today have been designed to link
Virtual Machines and Object Storage.
8. The answer: Open vStorage
Open vStorage turns Object Storage into Virtual Machine usable
primary Storage!
9. What is Open vStorage
Open vStorage is an open source “Grid Storage Router" installed as a
virtual machine on a host or a cluster of hosts to create a VM-centric,
clustered, reliable, scale out and high performance storage system for
virtual machines out of Storage Backends such as Object Stores.
10. An Overview
ESXi / KVM ESXi / KVM ESXi / KVM
Scale-outVM VM
VM VM
VM VM
VM VM
VM VM
VM VM
Unified Namespace
...
Swift
SS
DSSD
Open
vStorage
SS
DSSD
Open
vStorage
SS
DSSD
Open
vStorage
11. Key aspects are
• Unified namespace presented as NFS to all Hosts
• Open vStorgae leverages server flash as acceleration
• Flexibility in storage backends
• Redundancy and Fault Tolerance in Software
• Asymmetric Scale Out Architecture
• VM-centric approach
• Multi-hypervisor
• Open-source: Apache License version, Version 2,0
12. Solving Eventual Consistency
TIME
LBA 1: A
LBA 2: B
LBA 3: C
LBA 4: D
LBA 5: E
LBA 1: F
LBA 1: A
LBA 6: G
LBA 2: C
LBA 3: D
LBA 4: E
...
SSD or PCI Flash
LBA 1: A
LBA 2: B
LBA 3: C
LBA 4: D
LBA 5: E
SCO 1
LBA 1: F
LBA 1: A
LBA 6: G
LBA 2: C
LBA 3: D
SCO 2
LBA 4: E
...
SCO 3
Transfer SCOs once they are full
to the Object Store at slow pace
Each write is appended
to the current SCO
Swift
...
13. How does it work ...
VM
VMDK
NFS
VM
Config
Open vStorage VSA
Distributed
Database
Volume
VM
VMDK
VM
Config
Volume
Storage Backend (Ceph, SwiftStack, ...)
Open vStorage VSA
VM
VMDK
VM
Config
Volume
Volume is only available on 1 Host!
14. Open vStorage: Summary
• Uses an always append approach
• Push Storage Container Objects to the Object Store once it is full
(at slower pace)
• Each Virtual Machine with the Open vStorage software has its own
NFS server and exports a different file system instance
• But each Host is tricked into believing that it accesses a single
unified namespace shared across all the Hosts (so vMotion is
supported)
15. Download the Open vStorage (it is free)
and give it a try!
http://doc.openvstorage.com/
Give it a try ...
