In the span of the decade between 2010 and 2020, storage volumes are expected to grow more than 50 fold. Market...
research firm IDC projects that by the end of 2020, data storage will top 40 zettabytes, equating to 1.7 MB of new data produced for each of the 7.5 billion people on Earth every second of every day. This escalating storage expansion coupled with ongoing pressures to cut IT costs is driving enterprises to not just re-evaluate their infrastructures, but, in many cases, to transform their architectures. Establishing tiers based on access needs for data is helping these enterprises manage the data growth and costs, and cold cloud storage is becoming an important part of this new tier-based world.
Cloud-based object storage presents a cost-effective, durable and very scalable alternative to traditional file or block storage -- in the appropriate use cases. Object storage is a particularly good fit for backup and disaster recovery use cases that are not that read- or write-intensive because the technology treats data as an object, rather than a fixed-sized block. In addition to the stored data, each object includes metadata that provides context and a unique identifier.
Demand for object storage is on a rapid growth path, driving providers to come up with options that leverage the model's scale and also accommodate archival use cases where the data rarely, if ever, needs to be accessed. Dubbed cold storage, this approach promises an even lower cost per GB than conventional object storage. The trade-off is that retrieval times are significantly longer -- hours instead of minutes. But for organizations compelled to store data for lengthy time periods for regulatory, legal and other reasons, cold cloud storage could be an ideal option.
Cloud behemoth Amazon Web Services (AWS) blazed the cold storage trail with its 2012 launch of the service it calls Amazon Glacier. Now, Microsoft, its closest infrastructure as a service competitor, is offering up an alternative with its Azure Cool Blob Storage that could give Amazon Glacier a run for its money. So how do the two offerings differ, and which is the better option?
Let's start with the pioneer: Amazon Glacier is billed as a secure, durable and, with a price as low as $0.007 per GB, extremely economical cloud storage service, ideal for data archiving and long-term backup. Glacier is targeted toward application workloads with only sporadic access requirements in which organizations have a several hour retrieval window. To make the product more palatable for compliance, Amazon Glacier Vault Lock allows organizations to set controls for individual Glacier vaults that can automate actions and policies, such as "time-based data retention," or lock a vault so it cannot be deleted.
Microsoft threw its hat into the cold cloud storage arena this year with the April roll out of its Cool Blob Storage offering. A complement to Microsoft Azure's established "hot" Blob Object Storage service for more frequently accessed data stores, the archiving product drops the stored data price down to as little as a penny per gigabit. While a little pricier than Glacier, at least for stored data (data retrieval, access and transfer pricing is separate), data can be retrieved in real time -- which is significantly faster than the hours Amazon Glacier promises.
Frozen apples to frozen apples
While Glacier is AWS' flagship cold cloud storage service, the Amazon Simple Storage Service (S3) Standard-Infrequent Access (Standard-IA) storage tier is comparable to the Azure Cool Blob Storage service. Introduced last year, Standard-IA is positioned as an archival storage option for customers that rarely need to access their data; but when they do require access, it offers faster retrieval times than Glacier provides. After a period of time, data can be moved to different storage tiers within S3 based on changing access requirements. AWS does set a minimum object size of 128 KB, which means customers are charged for at least a 128 KB data store even if their storage objects total less than that.
AWS and Microsoft Azure offer comparable availability guarantees and similar, but not identical, security controls for their cold storage offerings. Both provide encryption and key management to data preflight and during the transfer. However, while Amazon provides server-side encryption, Microsoft Azure has plans to implement it, but is not yet offering postflight encryption.
AWS delivers S3 Standard-IA from facilities in all zones. Microsoft has some delivery gaps it has said it will close soon. Regions to which the company is still not delivering the service include Australia, Singapore, South America and the western United States.
AWS and Microsoft offer comparable scale and feature sets in Amazon Glacier and Azure Cool Blob Storage. Picking one cold cloud storage service over the other may primarily come down to cost. But which service is more economical depends very much on the use case. Depending upon factors such as object size, location and frequency of access, one service may win out over the other on cost, but it is not as easy as looking at just stored data pricing. It is crucial to assess, upfront, which product is the most cost-effective and meets all of your enterprise criteria before committing to a cold storage service.
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