Autor: Alexander Eichhorn

Network Storage


Network-attached storage (NAS)  

NAS is a storage server connected to a computer network that provides remote file access to heterogeneous clients running different operating systems and application software. An NAS server is optimized for I/O intensive workloads and storage capacity, often using custom-built hardware and software. NAS servers contain multiple high-capacity storage drives, often arranged in RAID configurations for data redundancy. Drive manufacturers offer special NAS versions of hard disks which are optimized for 24x7 operation, low vibration and faster error recovery to improve their compatibility with software and hardware RAID controllers.

NAS servers are made for convenience. They are self-contained appliances that come with a pre-installed and pre-configured operating system, so a user must only add hard drives to start working. Configuration such as user and volume management, software updates and monitoring happens through a remote Web interface. An NAS usually offers different kinds of networked file systems (e.g. NFS, SMB, AFP) for remote file access by heterogeneous clients. Besides that, some NAS solutions include additional business-relevant services such as shared calendars (CalDAV, WebDAV), email and web servers, load balancers, VPN services, backup services, print services, etc. 

Storage area network (SAN)

A SAN is a storage system that provides block-level data storage to servers over a computer network. From the viewpoint of a server, a SAN looks like a regular directly attached disk drive. A SAN does not provide a file abstraction or any filesystems. SANs are used to connect large libraries of disk arrays, tape libraries, and optical storage jukeboxes to servers. The word network in SAN stems from the fact that a SAN is typically built from multiple appliances connected via a private network separate from the local server network. Commonly used SAN protocols are Fibre Channel, iSCSI, ATA over Ethernet.

SANs are primarily made for data centers and customers with very large data sets. They make the management of storage more flexible by allowing shared access for multiple servers (e.g. email, databases, file servers). SANs allow the control of Quality of Service parameters (bandwidth, latency) on a per-node bases. This is particularly used in video editing workflows, where editing and playout clients are directly attached to the SAN to eliminat intermediate file servers for higher and predictable performance. 

Object stores

An Object store is a data storage architecture that manages data units as individual objects. An object has a unique identifier and contains the actual data plus a variable amount of custom metadata. This is different from file systems where files are identified by their hierarchical file name and metadata is fixed to a pre-defined set. In object stores a file name is just another metadata entry. Popular object stores are Amazon S3, OpenStack Swift, Google Cloud Storage and Microsoft Azure.

Object stores allow for inexpensive and scalable operation. Metadata management is separate from data placement, a single object store can span many physical servers and data replication is performed on an object level. There is no more need for storage-level redundancy (RAID arrays of disks) because objects are already replicated across many servers and many attached disks. 

Media Asset Management

MAM systems are storage servers specialized for the ingest, annotation, cataloguing, retrieval and distribution of digital file-based media assets such as digital video, audio and image files. A MAM usually stores a target version, so called essence, which is the highest fidelity representation of an asset, together with some lower fidelity proxy versions and metadata about the asset.

A MAM typically consists of a database that stores metadata about managed assets and some attached solution for file storage such as an object store or a NAS. MAMs are configured and accessed via Web frontends or native client applications running on a desktop or mobile OS. Some vendors make plugins for existing creative software like video editing or compositing tools available, so the integration into production workflows becomes seamless.

Related Articles: