Block Storage explained

When it comes to storage, the main emphasis is placed on how much space is available. Whether it is in a local system or the cloud, the amount of storage space must satisfy the users’ relevant needs. Storage takes on different forms though, and there is more than one way for systems to store data. The interplay of numerous aspects such as speed and efficiency in terms of memory usage always plays a role here.

Users can choose between block storage, file storage and object storage. Each system has its advantages and disadvantages. We explain what characterises block storage.

Whereas entire files are stored in a folder system in the case of file storage, for example, block storage stores data in the form of blocks in a location regarded as the most suitable by the system. In this process, the files are split evenly into blocks. The files therefore lose their actual meaning and cannot be readily executed or opened. Blocks are units of the same size. In order to retrieve the individual blocks, an address is assigned to each of them. If the server receives a request, it can locate the files, merge them back together and then deliver them.

Block storage is usually implemented in a Storage Area Network (SAN). Here, several servers have access to data storage through a network. This is all controlled by a software program that locates the blocks. Although block storage in an SAN was originally set up like a LAN with switches and hubs, today it can also be implemented in cloud environments. We usually call this block-level storage. This simulates an interrelated system comprising hard drives as would have been used traditionally.

In an SAN, a Fibre Channel (FC) or Internet Small Computer System Interface (iSCSI) is normally used for communication. An FC is an interface that was developed for ultra-fast transmission. However, the iSCSI method uses TCP and Ethernet and can therefore be easily integrated into existing networks.

Compared with other forms of data storage, block storage is considered especially fast and highly redundant. Each block has its own address through which the data can be called up. Other storage methods use metadata for this, and in some cases, substantial amounts of it. The lack of this additional information can be both advantageous and disadvantageous. Although the blocks are kept extremely streamlined and can be called up directly, you will need an additional database if you want to store metadata specifically. The biggest downside of block storage is its price, because SANs require expensive hardware.

Block storage comes into its own in databases. This is because of the high speed at which the data can be both read and written. Transactional databases have to be constantly adapted. Block storage produces excellent results in this application, unlike other storage methods where waiting times are to be expected. That is not ideal, especially in corporate applications. Block-level storage is also used in virtual machines. The technology makes it easy to provide storage for virtualisation.