What is object storage?
Using a different method of storing data – object storage manages objects as opposed to blocks or files (managing the files as objects).
Objects are addressed using a unique identifier in the same way that files in a file-based storage system are addressed via a full path. Objects are stored in a flat address space thus creating a simple, more scalable storage space.
What are its characteristics?
- Metadata – Objects consist of metadata which provides contextual information about the data within the object or actual data. Metadata in objects can be filled with any number of custom attributes, as opposed to file-based storage systems where metadata is limited to file attributes.
- Fixed Objects – It is a fixed content repository which cannot be updated in place. Objects are updated by creating new object versions. One of the benefits of this is that it simplifies multiuser access and removes the challenges of file locking. If multiple users access the same file at the same time, the object storage system will just write different versions of the file.
- Protocol Support – Object storage is usually accessed through a REST API over HTTP. These are done via a set of simple commands. Put: this creates an object. Get: this reads an object. Delete: purges an object. List: this lists objects. Using this method, it improves availability of storage over long distance (geographically).
- Redundancy – Redundancy and high availability are accomplished by storing multiple copies of the same object on multiple nodes. Depending on the policies in place, an object is created on a node and then copied to other nodes. This can be at the same location or a completely separate site, something that is highly complex to achieve with block or file storage due to the latency constraints.
What is it used for?
Due to object storage being inadequate for transactional data, which changes frequently, its uses lie beyond NAS and file shares. It works well for unstructured data that isn’t updated regularly, either as a secondary storage tier behind transactional storage, or for archiving purposes. One of the most common examples of object storage would be Amazon’s Glacier.
In my next article I will dive deeper into the world of storage and everything it has to offer.