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Disk array

Every business should have data collection space. Depending on the conception, whether a company uses cloud solutions or opts for using its own IT infrastructure, it should choose disk array or a set of data collection arrays. Disk array is a very general term and currently a series of technologies and standards are used that determine the intended use of a device for certain purposes. That is why before the purchase and the disk array deployment in a company you should run an analysis in terms of the demand for certain technical criteria and administrative features and based on them choose an adequate device. Below you will find the description of the disk array key technical criteria groups.


The essential feature of disk arrays is their resistance to the failures of certain device components including hard disks or SSD disks. RAID systems, and there are a few of them, protect the device against a failure of several subsystems. They determine the level of redundancy of the data saves on the magnetic media or SSD disks. The level of redundancy influences the amount of available disk space for the user and the data recording and reading speed. The amount of IOPS or the operations per second determine the type of the used RAID system which should be chosen according to the device intended use.


SAN and NAS are two approaches sharing the bulk memory resources outside. In the SAN concept the disk array space is shared through the Fiber Channel protocol or the iSCSI server. At the same time the server is equipped with special HBS Host Bus Adapter cards so that the disk array resources are seen by the server as disks mounted directly on the server. The disk array shares the space on the level of disk blocks. In the NAS concept the disk array resources are shared through one of the file server protocols, most often it is the NFS protocol. The array shares the disk space on the files level. Most of the modern arrays enables the mixed work operating mode, however, additional licenses are often required. The choice of the operating mode during the disk array deployment should be influenced by the task types the disk is dedicated for. Both SAN and NAS have their pros and cons.

HDD, Hybrid or ALL-Flash?

The disk arrays can be categorized depending on the disks used in the device. We can use the conventional HDD disk, the hybrid solutions that apart from using the HDD disks also uses the SSD disks as cache for the data recording and reading operations or the arrays equipped only with the so- called All-flash SSD disks. Obviously, the fastest are the all-flash devices that are most often new structures built and optimized for the SSD disks. The all-flash devices also have an additional functionality such as the in-flight deduplication which was impossible in case of the conventional solutions equipped with the HDD disks. On the other hand, there are the solutions equipped only with the HDD disks. This type of disk arrays have significantly lower efficiency than the all-flash solutions but they are relatively cheap. The speed obtained thanks to the HDD disk and the adequate RAID system deployment is enough to perform a range of tasks at a modern-day company. An indirect solution are the arrays with hybrid volumes where a few SSD disks are added to the conventional data on the HDD disks that play the cache memory role for the recording and reading operations.

Additional functionality

Modern disk array are in fact servers equipped with a big amount of hard disks and a specialized operating system which often takes up hundreds of gigabytes. The array operating system except for providing the basic functionality in the form of data serving has additional labor-saving features for the whole solution. Among the most common solutions are:

  • Deduplication – it is the disk space optimization on the array. The array operating system checks if the given data blocks do not reoccur on the device and if they do the system automatically connects the data with only one block and deletes identical copies.
  • Snapshot – the recording to the same data is performed to separate blocks on the device so that the array operating system can keep the previous data copy. The snapshot shutter is triggered on demand or at certain intervals
  • Replication – it means the data copying between devices, modern disk arrays support a series of data replication from a basic copy to metrocluster solutions where the recording is performed synchronically to all the devices in the cluster.
  • Data encryption – modern solutions have the data encryption algorithms implemented on the disk arrays.
  • VAAI – a cooperation standard of the virtual machine host working under control of the VMWare system with the disk array, the VAAI protocols speed up some of the array operations by sending special control commands.


SDS or Software-defined storage as one of the hyper-convergence environment aspects makes the data space independent of the hardware layer. In effect it means the virtualization device deployment, i.e. the VMWare with the vSAN service on the servers equipped with a big amount of hard disks without any external specialized array for data storage. VSAN solutions are most often used for the double-node cluster deployment without the dedicated data array.

Disk array deployment and administration

Partner24 provides IT services in business IT support. We are competent in the deployment and administration of the disk arrays and servers. Partner24 runs the IT audit of the solution and based on our experience offers an adequate disk array solution or hyper-convergence service deployment.