Swift is OpenStack's scalable object storage system that stores unstructured data and provides a RESTful API similar to S3. It is designed to be highly available, distributed, and scalable up to several petabytes. Swift uses a consistent hashing algorithm to partition and replicate data across multiple servers. Components include proxy, account, container, and object servers that each have specific roles in storing and managing objects, metadata, and namespaces.

1. Openstack Swift
An Introduction

2. What is Swift?
Object Store
Analogous to S3
Blob store
Does not care about type of data
Apache Licensed (Python)
Production Quality

3. Features
Distributed
Scalable to several Peta-Bytes
Eventually consistent (CAP)
Highly Available (by design)
Robust
REST-in peace :)

4. Features (contd..)
S3 API support
Can work on commodity HW
Quotas and access control
Various Storage Systems
Keystone Authentication

5. But...
You can't:
mount it
have file hierarchies (?)
store live databases
format to a file system
do anything the API does not let you do !
Store objects sized > 5GiB (WIP)

6. Components
Proxy
Account Server
Container Server
Object Server
Rings
Auditors & Expirers
...

7. Proxy Server
Gatekeeper
Authentication
Handles req from other servers
Single point of failure?

8. Object Server
Stores the objects
Size restricted to less than 5 GiB
Storage, retrieval and deletion
Updates & Replication
Integrity audits
Extended attributes

9. Container Server
Keeps track of objects
Namespace partitioning
Lists objects
SQLite DBs
Globally unique names not necessary

10. Account Server
Keeps track of containers
Lists containers and points to them

11. The Rings
Consistent hash ring / table
Partitions & Replicas
Weights
Object, Container, Account servers have their
own rings

12. http://docs.basho.com/riak/latest/references/appendices/concepts/

13. Swift Rings by @juldanjou

14. Thanks to Julien Danjou

15. Auditors & Updators
Detects bit-rots / filesystem corruption
Quarantines
Updators check for list sanity
Counters & metadata

16. Replicators
Ensures enough replicas
Ensures correct placement of replicas
Replication mechanism - Rsync

17. Expirers
Deletion of an object
Tombstones .ts
swift-account-reaper

18. Monitoring & Stats
swift-recon
swift-informant
Graphite / Ganglia
StatsD

19. Questions ?
swift.openstack.org