Amazon AWS Storage Options   Leave a comment

By: Kevin Gilbert 

Amazon provides several AWS storage options. This can be confusing if you are new to AWS.

Instance Store – When  you start a new instance from an Amazon AMI template, it will launch in Instance Store storage. Instance Store Storage can be used for an instance’s root device. This provides a very cheap option because you only pay for the instance, not the root instance store. You can get better performance then the other options. However, the storage is not persistent. It uses ephermeral drives – if you terminate your instance the volumes are destroyed and your data is lost. Also, root devices are capped at only 10GB, but you can have a 1.6TB data volume.

Elastic Block Storage – Elastic Block Storage is an option for instances. It provides faster boot time. If you terminate an instance the EBS volume detaches and remains available to reattach to another instance. Volume sizes are only 1TB, but you can use software RAID or span drive letters across multiple volumes so that’s not a big deal. EBS holds many advances compared to Instance Store however EBS is more expensive. Also, some people are concerned about EBS because they were burned during the April 2011 EBS outage which took EBS offline for some customers.

S3 –Simple Storage Service is large amounts of cheap and relatively slower disk (but not slow enough that you’ll probably notice). The storage is normally accessed through a web brower but can also be accessed through command lines. S3 doesn’t need to be mounted or connected to an instance in order to be viewed. There are some third party tools that will mount S3 as a drive letter and then do the command line operations in the back ground. Individual objects can be up to 5 terabytes in size. For high reliability, data is stored in multiple data centers within your region. Unlike Instance Store and EBS, an instance’s root drives can not run from S3. While an instances’s data drives can be in S3 by using some third party tools that mount S3 storage as drive letters, that really isn’t the intention of S3. The intention of S3 is for static data such as backups and web pages.

Reduced Redundency Storage – RRS is S3 storage with a lower SLA. It provides 99.99% uptime instead of 99.9999999999%. While S3 can survive a two datacenter outage, RRS can only survive a single data center outage. To select RRS it is a simple check box when uploading files or a checkbox within the file’s properties. RRS is significantly cheaper then the normal S3 storage.

Now that you’ve seen the various storage that is available in AWS, you can get creative on how you use it. For example, some will  boot an instance built on Instance store (because it is cheaper) and as part of the boot process, copy their data that they’ve backed up in S3 to the Instance Store volume. Therefore they don’t care that instance store is not persistent because their current data is available in S3. Others choose to run databases within EBS because they don’t want to lose their data should their instance get terminated.

Posted October 1, 2011 by cloudbusterspodcast in Uncategorized

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