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The versatility of SAN-attached storage

What benefits could your business see from SAN-attached storage? Find out below. 

This article first appeared on the Lenovo blog:

Guest blog by Ted Vojnovich

The definition of SAN-attached storage is external storage attached to application servers via a network. It is important to point out that the network involved can be attractive, low-cost Ethernet or Serial Attached SCSI (SAS) networks as well as traditionally higher-cost Fibre Channel networks. The usage of low-cost networks and affordable SAN-attached storage dispels the conception that SAN-attached storage equals expensive storage. As a result, it is worth reexamining the benefits and attributes of SAN-attached storage.

For entry workgroups, SAN-attached storage enables data management on a tight budget. For larger enterprises, it provides flexibility to change or grow with application requirements. Other SAN-attached storage benefits include the sharing of data and resources and the management of data via rich data management services. These benefits make SAN-attached storage a compelling option compared to other storage approaches. Let’s discuss these benefits in more detail.

First, and foremost, SAN-attached storage enables sharing, which encompasses several components. Sharing provides opportunities to optimize data usage in terms of data collaboration and efficiency. These sharing models include:

  • Sharing of data between several applications or clustered applications on clustered or scale-out servers.
  • Sharing of storage where one storage unit or product can host data for several independent applications on independent application servers.
  • Sharing of data services such as data backup utilities or data snapshot services.
  • Sharing of data networks between storage, servers, applications and clients.

Second, SAN-attached storage provides a rich set of data management services typically not found in data management for direct-attached storage (DAS). Data management services benefit the user by providing the ability to allocate and optimize storage for data access and protection. For SAN-attached storage, data management services typically include many of the below capabilities:

  • Storage virtualization services that abstract tiers of physical storage into storage pools.
  • Snapshot services that capture the data at a specific point in time for later or ulterior usage.
  • Thin provisioning services that manage the physical allocation of storage based on actual needs.
  • Compression services that reduce the size of the actual data placed on storage.
  • Replication services that provide disaster recovery copies of data for timely data restoration.
  • High-availability services to ensure access to data even if a physical subsystem fails.

Third, SAN-attached storage can actually be cost effective — even for small installations that have tight budget constraints. This cost effectiveness can be realized in several ways.

  • Cost-effective fabrics act as interconnects between application servers and storage either by using relatively low-cost SAS or iSCSI. In the case of iSCSI, the cost effectiveness can be even more compelling if the underlying Ethernet fabric is shared with client-server traffic as well as server-storage traffic.
  • Cost effectiveness as compared to some recent technologies such as scale-out configurations. Scale-out configurations are comprised of high-cost storage software running on low-cost hardware that is directly connected to groups of disks. In many cases, the storage software in scale-out solutions is considerably higher — in terms of cost as well as storage capacity used to protect the data — than SAN-attached storage.

Fourth, SAN-attached storage can evolve as storage requirements evolve. This evolution can include the following scenarios.

The storage configuration can increase in several dimensions.

  • An increase in usable storage capacity by adding larger or more drives.
  • Increasing connectivity with servers and applications.
  • Increasing usefulness with the advent of new storage technologies or storage features.

SAN-attached storage can host data for additional applications with currently unused storage capacity or with additional storage capacity.

The benefits I’ve discussed make SAN-attached storage very versatile. Compared to DAS, SAN-attached storage distinguishes itself in several key ways.

  • SAN-attached storage can scale to much higher capacities than DAS.
  • SAN-attached storage can offer significantly higher performance than server software managing storage such as Microsoft Storage Space or VMware VSAN (and can provide a much more efficient use of storage at a given performance metric that server software managed storage).
  • With prudent selection, SAN-attached storage can be very economical compared to DAS or scale-out storage software managed storage.
  • SAN-attached storage provides high availability for data accesses more efficiently.

With sharing and rich data-management capabilities, SAN-attached storage offers customers a versatile option for storage solutions — providing traditional enterprise storage capabilities at a low cost. Find out more about Lenovo SAN products

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