Site icon Davoud Teimouri – Virtualization and Data Center

What’s SDS (Software-Defined Storage) – Part 2 (Ceph)

In the previous post, I have reviewed Software-Defined Storage concept and its benefits. At this part, we want to review one of open-source solutions for software-defined storage. As reducing cost is one of most important goal for migrating from other storage solutions to software-defined storage, using an open-source solution will help you to achieve that.

What’s Ceph?

Ceph is a distributed object store and file system designed to provide excellent performance, reliability and scalability. The name “Ceph” is an abbreviation of “cephalopod”, a class of molluscs that includes the octopus.

Introduction to Ceph

Whether you want to provide Ceph Object Storage and/or Ceph Block Device services to Cloud Platforms, deploy a Ceph Filesystem or use Ceph for another purpose, all Ceph Storage Cluster deployments begin with setting up each Ceph Node, your network, and the Ceph Storage Cluster. A Ceph Storage Cluster requires at least one Ceph Monitor, Ceph Manager, and Ceph OSD (Object Storage Daemon). The Ceph Metadata Server is also required when running Ceph Filesystem clients.

Ceph stores data as objects within logical storage pools. Using the CRUSH algorithm, Ceph calculates which placement group should contain the object, and further calculates which Ceph OSD Daemon should store the placement group. The CRUSH algorithm enables the Ceph Storage Cluster to scale, rebalance, and recover dynamically.

The power of Ceph can transform your organization’s IT infrastructure and your ability to manage vast amounts of data. If your organization runs applications with different storage interface needs, Ceph is for you! Ceph’s foundation is the Reliable Autonomic Distributed Object Store (RADOS), which provides your applications with objectblock, and file system storage in a single unified storage cluster—making Ceph flexible, highly reliable and easy for you to manage.

Ceph’s RADOS provides you with extraordinary data storage scalability—thousands of client hosts or KVMs accessing petabytes to exabytes of data. Each one of your applications can use the objectblock or file system interfaces to the same RADOS cluster simultaneously, which means your Ceph storage system serves as a flexible foundation for all of your data storage needs. You can use Ceph for free, and deploy it on economical commodity hardware. Ceph is a better way to store data.

Ceph’s CRUSH algorithm liberates storage clusters from the scalability and performance limitations imposed by centralized data table mapping. It replicates and rebalances data within the cluster dynamically eliminating this tedious task for administrators, while delivering high-performance and infinite scalability.

Ceph uniquely delivers object, block, and file storage in one unified system.

Ceph Object Storage

Ceph’s software libraries provide client applications with direct access to the RADOS object-based storage system, and also provide a foundation for some of Ceph’s advanced features, including RADOS Block Device (RBD), RADOS Gateway (RGW), and the Ceph File System (CephFS).

Ceph Object Gateway is an object storage interface built on top of librados to provide applications with a RESTful gateway to Ceph Storage Clusters. Ceph Object Storage supports two interfaces:

Benefits are as follows:

Ceph Block Device

Ceph’s object storage system isn’t limited to native binding or RESTful APIs. You can mount Ceph as a thinly provisioned block device! When you write data to Ceph using a block device, Ceph automatically stripes and replicates the data across the cluster. Ceph’s RADOS Block Device (RBD) also integrates with Kernel Virtual Machines (KVMs), bringing Ceph’s virtually unlimited storage to KVMs running on your Ceph clients.

Ceph RBD interfaces with the same Ceph object storage system that provides the librados interface and the Ceph FS file system, and it stores block device images as objects. Since RBD is built on top of librados, RBD inherits librados capabilites, including read-only snapshots and revert to snapshot. By striping images across the cluster, Ceph improves read access performance for large block device images. Benefits are as follows:

Ceph FileSystem

Ceph’s object storage system offers a significant feature compared to many object storage systems available today: Ceph provides a traditional file system interface with POSIX semantics. Object storage systems are a significant innovation, but they complement rather than replace traditional file systems. As storage requirements grow for legacy applications, organizations can configure their legacy applications to use the Ceph file system too! This means you can run one storage cluster for object, block and file-based data storage.

Ceph’s file system runs on top of the same object storage system that provides object storage and block device interfaces. The Ceph metadata server cluster provides a service that maps the directories and file names of the file system to objects stored within RADOS clusters. The metadata server cluster can expand or contract, and it can rebalance the file system dynamically to distribute data evenly among cluster hosts. This ensures high performance and prevents heavy loads on specific hosts within the cluster. Benefits are as follows:

Ceph Architecture

Ceph uniquely delivers object, block, and file storage in one unified system. Ceph is highly reliable, easy to manage, and free. The power of Ceph can transform your company’s IT infrastructure and your ability to manage vast amounts of data. Ceph delivers extraordinary scalability–thousands of clients accessing petabytes to exabytes of data. A Ceph Node leverages commodity hardware and intelligent daemons, and a Ceph Storage Cluster accommodates large numbers of nodes, which communicate with each other to replicate and redistribute data dynamically.

Ceph Architecture

Minimum Hardware Recommendations

Ceph can run on inexpensive commodity hardware. Small production clusters and development clusters can run successfully with modest hardware.

Further Reading

External Links

See Also

What’s SDS (Software-Defined Storage) – Part 1 (Overview)

Exit mobile version