This educational blog presents a high-level overview of Storage Area Networks (SAN) solutions in the cloud. For more information on software-defined cloud storage start with our product page: Lightbits Storage Platform for any Cloud.
What is a Storage Area Network (SAN)?
A SAN is a network of storage devices that offers a pool of shared block storage for multiple computing devices. SANs first appeared in the mid-1990s as a viable alternative to Direct Attached Storage (DAS) and NAS (Network Attached Storage) for high-speed, mission-critical analytic and transactional workloads like databases that require scalable storage and that can deliver high IOPS and low latency. They are also well-suited for virtualized environments which accelerated their adoption.
A SAN consolidates storage in a single block-level storage area, allowing users to access and manage data from a central location. To maintain high storage traffic and network performance, the SAN is typically implemented via a separate network infrastructure from the local area network (LAN).
Compute servers connected to the SAN gain access to whatever storage devices are on SAN controllers, such as tape libraries, local storage, and disk arrays. This design also offers the advantage of centralized storage management. SANs also help with improved storage security. With data in a centralized, shared SAN storage architecture, an organization can apply consistent policies for security, data protection, and disaster recovery (DR). A SAN potentially enables multiple backups of its data, and its block-level access helps improve application availability.
The design of the SAN also lends itself to dynamic fail-over, which helps with availability and business continuity. The SAN’s network fabric of interconnected storage devices and computers further improves availability. If one network path is disrupted, the SAN enables an alternate path. This way, it’s less likely that the failure of a single device will render storage inaccessible.
What are Two Main Technologies and Interfaces for SAN
SANs usually use one of two main technologies to move data in and out of storage: Fibre Channel and Internet Small Computer Systems Interface (iSCSI). Fibre Channel is a high-speed data transfer protocol. It provides lossless delivery of raw block data on an “in-order” basis. Fibre Channel is typically based on optical fiber cables, but they can also use copper cables. (The word “fibre” was adopted by the industry rather than “fiber” to avoid confusion over whether the protocol can only run on fiber optic equipment.)
Fibre Channels support data rates that include 1, 2, 4, 8, 16, 32, 64, and 128 gigabits per second. Architecturally, the switches in a Fibre Channel network operate in unison, effectively as one big switch that comes together to form a switched fabric.
iSCSI is a transport layer protocol operating atop Transport Control Protocol/Internet Protocol (TCP/IP). With this design, iSCSI makes possible block-level SCSI data transport between two components, the iSCSI initiator and the storage target, over TCP/IP networks. SCSI is a block-based command set connecting devices to networked storage. The iSCSI target can be a SAN controller, which exposes remote volumes that appear as local drives to host systems.
iSCSI is generally less costly than Fibre Channel because it connects servers to storage without requiring expensive Fibre Channel Host Bus Adapters (HBAs), switches, or cabling. Fibre Channel SANs also require admins who have specialized skills. In contrast, administering an iSCSI SAN, which runs on standard, existing Ethernet, is simpler. An IT generalist can easily learn to install and manage an iSCSI SAN.
What are the Pros and Cons of Storage Area Network (SAN)?
Their widespread use in on-premises datacenters notwithstanding, SANs have a number of disadvantages. For one thing, SANs are expensive, they can cost hundreds of thousands of dollars and require proprietary hardware. Because they require proprietary hardware, their provisioning cycles can be long, especially during times when supply chains are compromised (e.g., during the COVID pandemic). The cost of setting up and maintaining the infrastructure can be significant. It can take some time before you see a return on investment. This makes SANs better suited for larger organizations that can afford to invest in capital and management costs.
They can be complex and thus difficult to manage. A SAN is built in layers, with connections between the underlying storage arrays, the SAN network switches, and the servers that use the SAN. Each layer, device, and connection requires ongoing administration and maintenance, incurring additional costs.
There are multiple locations for faults and patching. Component upgrades and interfaces need frequent, if not constant attention. Indeed, various SAN components are not known for “playing nicely” together. SAN vendors often use proprietary protocols and management tools, which further complicate the task of SAN management. Additionally, SAN becomes a bottleneck in all-flash storage environments, which are now becoming the norm in most enterprises.
The complexity of SANs can require specific expertise to manage and maintain. Overseeing the SAN inevitably becomes a job for someone or even an entire team. When an organization has more than one SAN the complexity and administrative load grow all the more strenuous. A virtualized SAN architecture can relieve some of the pressure on admins to take care of hardware but presents its own complexity at the same time.
Security is also an issue, despite the uniform policy advantages highlighted above. A SAN is almost always a shared environment. As a result, it is vulnerable to lateral attacks, where a malicious actor gains access to one area of the SAN but then moves across it to breach data held elsewhere in the network.
That being said, while there are numerous cons there are benefits of SANs, such as high performance, scalability, and centralized management. Many organizations implement SAN to enable workloads that require high-speed data transfer rates and low latency. They can also be easily scaled and enable centralized management of storage resources, simplifying administration and improving efficiency in managing large amounts of data.
Other attractive benefits are redundancy features and multiple paths to storage devices, ensuring high availability and fault tolerance. SAN systems can facilitate efficient data backup and recovery processes, allowing for faster and more reliable data protection strategies. Also, it should be noted that SANs work well with virtualized and containerized environments.
What is Cloud SAN?
Cloud SAN (Storage Area Network) refers to a cloud-based implementation of a traditional SAN. This model delivers block-level storage services over a network, typically the internet or a dedicated network connection. It delivers the benefits of traditional SANs to the cloud environment, offering enhanced flexibility, scalability, and cost efficiency while maintaining high performance and reliability.
Just like traditional SANs, Cloud SAN provides block-level storage, where data is stored in fixed-sized blocks. The physical storage devices are abstracted into a pool of storage resources that can be dynamically allocated to meet demand.
By moving to a cloud-based SAN, you can reduce the costs associated with maintaining physical hardware and the complexities of a traditional SAN setup. Instead, you can pay only for the storage you use.
This type of storage is suitable for applications requiring high performance and low latency, such as transactional databases that require fast read/write speeds and high availability and virtual machines.
What are the Pros and Cons of Cloud SAN?
Cloud SANs offer significant benefits in terms of scalability, cost efficiency, and ease of management. However, they also come with potential drawbacks such as latency issues, and security concerns.
Depending on the distance to the cloud location, cloud SAN models can introduce latency, which negatively impacts performance. This can be particularly problematic for applications that require real-time data access. In addition, a lot of organizations have cost sensitivities and while cloud storage costs might be lower, data transfer (ingress and egress) can incur additional fees, potentially leading to higher overall storage costs for data-intensive operations.
A final consideration is that you may have less control over your storage environment in the cloud compared to your on-premises data center, and your customization options might be limited by the cloud provider’s offerings.
Additional Considerations for Cloud SAN
- When using a Cloud SAN model, it is essential to consider data compliance and residency regulations, which mandate where data can be stored and processed.
- Evaluate how well the Cloud SAN integrates with your existing systems and applications. Ensure interoperability with your current infrastructure to avoid disruptions and additional costs associated with reconfiguration.
- Review the SLAs provided by your cloud vendor to understand the guarantees regarding uptime, performance, and support. A reliable SLA can ensure that your Cloud SAN meets your business continuity and performance requirements.
- Plan for the migration process to the Cloud SAN. This includes data transfer methods and downtime minimization strategies.
- Implement robust performance monitoring and management tools to track the performance of your Cloud SAN. This ensures that you can quickly identify and resolve issues and optimize storage usage.
- Consider if a hybrid cloud model might be beneficial, where critical data resides on-premises while leveraging cloud SAN for less sensitive, scalable storage needs. This can provide a balance between control and flexibility.
- Ensure your Cloud SAN has robust data protection measures, including regular backups and snapshots.
- Ensuring that your Cloud SAN can evolve with advancements in technology can protect your investment and future-proof your data storage system.
Lightbits “SAN in the Cloud”
Lightbits software-defined storage brings a SAN experience to the cloud. You provision, manage, and pay for storage resources as a pool instead of volume by volume. For large-scale migrations, you won’t need to spend weeks sizing each volume individually, and you won’t have to over-provision for maximum expected throughput or capacity, unlike native cloud storage options that work on a direct attached storage model. With Lightbits, you can scale performance and capacity independently.
For even greater efficiency and cost reduction, Lightbits uses thin provisioning and compression to conserve capacity. That means you can size your volumes for the future but only pay for consumption today. You won’t need to predict maximum capacity and pay for underutilization. At the same time, your Lightbits software licenses are portable between on-premises and public clouds.
Where native cloud storage communicates with applications over a limited bandwidth storage network, Lightbits leverages the network speed of NVMe/TCP to deliver higher throughput and consistently lower latency to your applications. Your users will continue to get an excellent experience during peak usage times. With Lightbits, you don’t have to pay for additional provisioned IOPS as you scale services.
Using a solution like Lightbits that leverages low latency NVMe storage and standard TCP/IP, you can deploy high-performing, clustered storage that is cost-effective and highly scalable—but without SAN’s traditional overhead headaches. If you want to try Lightbits high-performance block storage as a “SAN in the cloud,” it is available on the AWS Marketplace and Microsoft Azure.
Conclusion
Understanding SAN in the cloud reveals the digital modernization potential of integrating traditional SAN benefits with cloud-based solutions. SANs have long been the backbone for high-performance, mission-critical applications, providing centralized, scalable, and reliable storage. However, they come with significant costs and complexities, which can be challenging for organizations to manage.
By carefully evaluating the pros and cons of Cloud SANs and considering factors like data compliance, SLAs, performance monitoring, and hybrid cloud integration, you can make informed decisions that align with your specific needs and future growth plans. Embracing a SAN in the Cloud architecture can pave the way for a more agile, cost-effective, and resilient storage infrastructure, supporting the evolving demands of modern workloads.
For further insights and to continue your learning journey, explore our blog “Why it Might be Time for SAN Replacement.”
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