Service Description Cloud Storage Openstack Swift

Transcription

1 Service Description Cloud Storage Openstack Swift

2 Table of Contents Overview iomart Cloud Storage... 3 iomart Cloud Storage Features... 3 Technical Features... 3 Proxy... 3 Storage Servers... 4 Consistency Servers... 4 Fault-tolerant... 5 Eventually Consistent... 5 Example Request Flow... 5 Client Data Designs... 5 Cloud Control... 6 Connectivity... 6 Service Management Details... 7 Pricing... 7 Support... 7 Information Assurance... 7 Ordering and Invoicing Process... 8 Service Lead Time... 8 On-boarding and Off-boarding... 8 Using the Service... 8 Termination Terms... 8 Service Credits... 9 Service migration... 9 Consumer Responsibilities... 9 Trial Services... 9

3 Overview iomart Cloud Storage Cloud Storage from iomart delivers unlimited storage capacity automatically without the requirement to invest in hardware and software, greatly reducing an organisation's capital expenditure. There is no limit to the size of the files than can be uploaded and the service is fully scalable and flexible, allowing organisations to scale their usage up or down depending on demand. Cloud Storage is an ideal solution for organisations which have a requirement to store large volumes of archive data or who are looking to extend their storage footprint without the need to invest in additional hardware or management. Alternatively, organisations which require a redundant solution for storing backup copies of data offsite can integrate the iomart Cloud Storage solution into their strategy. The Cloud Storage service is hosted in iomart's wholly-owned network of secure UK data centres. All data is written to three separate disk arrays and in the unlikely event of a disk array failure, all data is then automatically copied to a new array. iomart Cloud Storage Features Simple API Secure storage Constantly Available Provides public or private storage Integrated with CDN Seamlessly extends local infrastructure Unlimited capacity Guaranteed service levels Third party ecosystem Pay as you go Cost effective storage Technical Features iomart Cloud Storage is based on the Openstack Object storage platform, Swift. It is a distributed, fault-tolerant, eventually consistent object storage system. The service is designed to be run on a cluster of computers rather than on a single machine and Swift is composed of three major parts: the proxy, storage servers, and consistency servers. Proxy The proxy server is a server process that provides the Swift API. As the only system in the Swift cluster that communicates with clients, the proxy is responsible for coordinating with the storage servers and replying to the client with appropriate messages. The proxy is an HTTP server that implements Swift s REST-ful API. All messages to and from the proxy use standard HTTP verbs and response codes. This allows developers building clients to interact with Swift in a simple, familiar way.

4 Swift provides data durability by writing multiple complete replicas of the data stored in the system. The proxy is what coordinates the read and write requests from clients and implements the read and write guarantees of the system. When a client sends a write request, the proxy ensures that the object has been successfully written to disk on the storage nodes before responding with a code indicating success. Storage Servers The Swift storage servers provide the on-disk storage for the cluster. There are three types of storage servers in Swift: Account, Container, and Object. Each of these servers provides an internal REST-ful API. The Account and Container servers provide namespace partitioning and listing functionality. They are implemented as SQLite databases on disk, and, like all entities in Swift, they are replicated to multiple availability zones within the Swift cluster. Swift is designed for multi-tenancy. Users are generally given access to a single Swift account within a cluster, and they have complete control over that unique namespace. The Account server implements this functionality, users set metadata on their account, and Swift aggregates usage information here. Additionally, the Account server provides a listing of the containers within an account. Swift users may segment their namespace into individual containers. Although Containers cannot be nested, they are conceptually similar to directories or folders in a file system. Like accounts, users may set metadata on individual Containers, and Containers provide a listing of each object they contain. There is no limit to the number of Containers that a user may create within a Swift account, and the Containers do not have globally-unique naming requirements. Object servers provide the on-disk storage for objects stored within Swift. Each object in Swift is stored as a single file on disk, and object metadata is stored in the file s extended attributes. This simple design allows the object s data and metadata to be stored together and replicated as a single unit. Consistency Servers Storing data on disk and providing a REST-ful API to it is not a hard problem to solve. The hard part is handling failures. Swift s Consistency servers are responsible for finding and correcting errors caused by both data corruption and hardware failures. Auditors run in the background on every Swift server and continually scan the disks to ensure that the data stored on disk has not suffered any bit-rot or file system corruption. If an error is found, the corrupted object is moved to a quarantine area, and replication is responsible for replacing the data with a known good copy. Updaters ensure that account and container listings are correct. The object updater is responsible for keeping the object listings in the containers correct, and the container updaters are responsible for keeping the account listings up-to-date. Additionally, the object updater updates the object count and bytes used in the container metadata, and the container updater updates the object count, container count, and bytes used in the account metadata. Replicators ensure that the data stored in the cluster is where it should be and that enough copies of the data exist in the system. Generally, the replicators are responsible for repairing any corruption or degraded durability in the cluster.

5 Fault-tolerant The combination of Swift s components allows a Swift cluster to be highly fault-tolerant. Swift implements the concept of availability zones within a single geographic region, and data can be written to hand-off nodes if primary nodes are not available. This allows Swift to survive hardware failures up to and including the loss of an entire availability zone, with no impact to the end-user. Eventually Consistent Swift achieves high scalability by relaxing constraints on consistency. While Swift provides read-yourwrites consistency for new objects, listings and aggregate metadata (like usage information) may not be immediately accurate. Similarly, reading an object that has been overwritten with new data may return an older version of the object data. However, Swift provides the ability for the client to request the most up-to-date version at the cost of request latency. Example Request Flow When an object PUT request is made to Swift, the proxy server determines the correct storage nodes responsible for the data (based on a hash of the object name) and sends the object data to those Object servers concurrently. If one of the primary storage nodes is unavailable, the proxy will choose an appropriate hand-off node to write data to. If a majority of the object servers respond with a success, then the proxy returns success to the client. Similarly, when an object GET request is made, the proxy determines which three storage nodes have the data and then requests the data from each node in turn. The proxy will return the object data from the first storage node to respond successfully. Client Data Designs Using any storage system effectively means understanding the characteristics of the system and the guarantees that the system provides. Swift is optimised for high concurrency rather than single-stream throughput. The aggregate throughput of a Swift cluster is much higher than what is available for a single request stream. A Swift client can take advantage of this by distributing data across multiple containers within an account. For example, backups may be stored by day or week in a container that includes that information in its name. Or a photo-sharing application may store images across many containers by using a prefix of the hash of the photo in the container names.

6 Cloud Control There is currently no control panel. Support is delivered via and phone. Connectivity Connecting the iomart data centres is a 20 Gigabit-per-second (Gbps) fibre ring which provides resilience and diversity to minimise the impact of a single transit failure. Three peering sites across this ring provide 10Gbit uplinks to our transit providers; Tiscali, Interoute, Cogent, and Teleglobe and iomart also maintains private peering connections with LONAP and LINX. All of our networking exchange hardware is housed in on-site dedicated cabinets. Each data centre network hub houses a Cisco Catalyst 7600-series modular switch, dual power supplies and a range of 7600-series fabric-enabled line cards to support both multiple fibre and copper gigabit connections. Automatic systems constantly monitor our entire network, transit links and servers. In the event of any problem, our data centre NOC teams are on site 24 hours a day. iomart holds on-site spares for critical equipment which powers our network to assist us in ensuring that we maintain our 100% uptime guarantee. Off Site Connectivity If you wish to access our Cloud Storage platforms via dedicated Internet Connectivity from your local office iomart can deliver dedicated network links straight into our Enterprise grade network. A wide

7 variety of options are available from 10Mb/s through to 1Gb/s circuits, with or without internet breakout. For further information on options for off-site connectivity please contact your iomart Account Manager. Service Management Details iomart assigns an Account and Technical Manager to each client. Our approach to Account Management has been developed to provide a value added service to our customers. Account Managers are focused on developing relationships, understanding each customer s strategic goals and supporting them in the achievement of their objectives. By understanding the demands placed on the organisation and the business drivers we are able to identify and recommend solutions that support customers in the achievement of those objectives. The Account Manager is also a single point of contact for any requirements or escalations, ensuring any issues are dealt with seamlessly and effectively. Pricing Description Cost per month ( ) Cost per GB data stored The pricing is based on per month. Charges are billed in arrears, based on data stored Pricing is exclusive of VAT. Support Support is provided on a 24/7 basis and the iomart NOC team responds immediately to monitoring alarms and support requests. The SLA specifies that all service affecting problems are dealt with in fifteen minutes. Information Assurance Business Impact Level s (IL) iomart Cloud Storage has been assessed as suitable for information systems classified to Official status - appropriate for IL3 data. All iomart data centres are located in the UK UKAS certified management systems to ISO 9001, ISO 27001, ISO and ISO 14001

8 Ordering and Invoicing Process Upon receipt of a completed Sales Order form, iomart will deploy the required service. Billing for the service is monthly, with a minimum contract term of one month. Payment can be via Direct Debit or BACS transfer. Service Lead Time New Cloud Storage customers are typically deployed within two working days from order. Shorter deployment times may be available and prioritized upon request. On-boarding and Off-boarding Once the deployment is completed, account and access details are sent to the Account contact nominated by the customer. The service will be ready for use. Support for the service becomes available immediately. When use of the service ends, the customer will be able to export the data before the service is terminated. Using the Service iomart is an active partner in the Openstack project and as such all Developer API documentation is available online at In addition to this, a wide range of third party applications come with prebuilt functionality which takes advantage of iomart Cloud Storage such as Cloudberry and Cyberduck. Termination Terms At the point of termination, all data, accounts and access will be permanently deleted, and will not be able to be recovered or restored. Thirty days notice required before termination takes place. It is the responsibility of the customer to remove all data prior to termination. There are no termination costs for this Service.

9 Service Credits iomart offers guaranteed service levels on network availability, power, data centre environmental conditions and support. In the unlikely event that we do not meet our stated levels we will credit your account. Service migration Where necessary, iomart can assist with data migration projects from existing providers. We can also arrange for data to be exported from iomart Cloud Storage if required using a wide range of methods and mediums. Generally speaking the approach to migration varies depending on a wide variety of factors please contact your Account Manager for further details. Consumer Responsibilities The control and management of access is the responsibility of the customer administrator. The customer is responsible for ensuring only appropriate data is stored within this environment and that they abide by iomart s Acceptable Usage Policy. Trial Services iomart offers customers a one month free trial of the service prior to contract.