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Object storage vs. block storage in the cloud

Object storage isn't your only choice when it comes to the cloud. George Crump digs into the benefits of alternative storage technologies such as NAS and block.

The main question facing most cloud providers today is which type of storage they should select. It's not accurate to assume that most providers need object storage. It depends on what the focus of the provider’s service will be. If it’s providing an application or hosting an application, block may be a better answer. If it's providing unstructured data storage, as would be the case with a backup service provider, file sharing provider or photo storage provider, then object storage in the cloud might be the best option. It's important to know how the main storage options for the cloud -- object storage vs. block storage, NAS and multiprotocol -- differ to determine which one is best suited to your needs.

The assumption is often that object storage is the de facto storage option for the cloud, but this is incorrect. Many cloud providers today provide an application as a service or host other organizations' applications. Most of these applications either require, or are best served by, block storage. Interestingly enough, many of the largest cloud providers have infrastructures that look very similar to their non-cloud counterparts. They have a series of hosts, densely populated with virtual machines that are connected over Ethernet or Fibre Channel to a traditional block-based storage system.

What generally separates the cloud provider from the traditional data center is not the storage but the level of automation. Typically, providers focus on automated provisioning of services and automated load balancing as performance fluctuates. Cloud providers that provide an application as a service or host an organization’s application should look for storage systems that are able to integrate into that organization’s automation strategy. This often means looking for block storage systems that are accessible via a RESTful API.

NAS as the best bet for legacy apps

The assumption is often that object storage is the de facto storage option for the cloud, but this is incorrect.

Like block-based storage, NAS systems also have a role in the cloud. This can be to support a traditional application that is now cloud hosted or to provide basic unstructured data storage. Most scale-out NAS systems can reach capacities similar to those of object storage systems. The key difference between a NAS system and an object storage system is the number of files or objects it can contain per file system. Since many applications can’t natively support object storage, NAS may be the best way to support these legacy applications, especially if the number of files that needs to be stored is within the limits of the particular NAS file architecture.

Object storage offers scale, data protection

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For large cloud providers, especially those that need to store a lot of discrete files, object storage in the cloud is a common choice. In addition to supporting a much higher file count than traditional NAS, most object storage systems are better suited to leverage high-capacity hard disk drives. This is because their data protection schemes are either replication or erasure coding, instead of RAID, which means recovery from a failed drive can occur more quickly. These data protection methods allow for granular data protection decisions based on file type, for example, so data can be accessed even after multiple failures.

Object storage infrastructures tend to be less expensive since they often are based on commodity hardware. Operationally, they tend to be the most programmable and easiest to tie into the provider’s automation strategy.

Multiprotocol could spawn a performance hit

Many object storage solutions now offer the ability to provide multiprotocol access, including iSCSI, NFS and CIFS. While the emulated presentations of these protocols may not perform as well as the native instances, for many providers that difference is negligible and it is far more valuable to have a single storage infrastructure instead of three.

At the same time, several NAS solutions have added the capability to present an object storage layer to their solutions. But similar to presenting block on object storage, object on NAS tends to not perform as well as the native solution. Typically, these blended models are only valuable if the organization has a minor need for the other protocol. In other words, you should purchase the storage system that natively supports what you most need.

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