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data as private or public access. Creation of bucket is non-chargeable. Amazon only charges for
storing objects into buckets on monthly basis.
In Amazon S3, files are stored as objects and objects are stored in a location called bucket.
According
to Amazon, S3 gives access to the same highly-scalable, reliable and secure
infrastructure that Amazon uses to run with its own global network of web services. Amazon
EC2 uses S3 to store Amazon Machine Images. The service has been developed to provide 99.99
percent availability and 99.999999999 percent durability of objects. Amazon even presents the
agreement offering credits to its consumers if availability of S3 service falls below 99.9 percent.
20.1.2.2 Amazon Elastic Block Store (Amazon EBS)
Amazon Elastic Block Storage (Amazon EBS) is a persistent storage designed specifically to
be used with Amazon EC2 instances. EBS provides raw block devices which is used to create
disk volume that can be attached to EC2 instance. EBS volumes are
like raw unformatted disk
drives that can be formatted using any file system of consumer’s choice (such as
ext3 or
NTFS).
EBS cannot function independently like S3. It can be used only with EC2 instances but data
is stored persistently independent to the life of instances. A volume can be attached to only one
EC2 instance and cannot be shared between instances. But, multiple volumes can be attached
to a single EC2 instance. The size of EBS volume ranges from 1 GB to 1 TB. Though EC2 does
not impose any limitation on the number of volumes that can be attached to an instance, it
depends on the operating system being used for the same. For security of data,
there is option
of launching the ESB volumes as encrypted volumes where all of the data are automatically
stored in encrypted form.
EBS is extremely reliable and provides high-operational performance with high-speed data
access and availability. ESB can be used to install relational databases (like Oracle, Microsoft
SQL Server or MySQL), NoSQL databases, enterprise applications (like SAP, Oracle) and so on.
20.1.2.3 Amazon S3 versus Amazon EBS
Simple Storage Service (S3) and Elastic Block Store (EBS) are two storage services offered by
Amazon. But they are not same and are to serve different purposes. EBS is meant to be used
with EC2 (Elastic Computing Cloud) instances and is not accessible
unless attached to some
EC2 instance. On the other hand, S3 is not dependent on EC2. S3 storage can be accessed
through any applications using HTTP protocol or with the open-source BitTorrent protocol.
Amazon S3 storage cannot be directly accessed. Some software or application is required to
access S3 since it communicates through web service interfaces (REST, SOAP and BitTorrent).
With EBS, once a volume is mounted on an EC2 instance, it can be accessed just like a disk
partition.
The storage in ESB is counted on volumes whereas in S3 it is
bucket where objects are
stored. The two systems differ on many other parameters if performance is measured. But
these cannot be treated as advantages or disadvantages as these two systems are made to serve
different purposes.
