We currently run some magnetic EBS volumes for data storage accessed by EC2 instances. Last month AWS announced the availability of Live Volume Modification with Elastic Volumes on EBS. This would enable a volume to expand while being in-use. Where as before you’d have to schedule downtime.
Live Volume Modification is almost a must-have feature for the web servers we run to be cost efficient and reduce any downtime. I have also noted that EBS Magnetic Volumes are now considered “previous generation” technology. (AKA: silent deprecation, just like reduced redundancy S3)
I attempted to expand a magnetic volume on a m3.large instance but found that the modify link was disabled. After a forum post, and the helpful reply from AWS, I found that previous generation magnetic volumes can not be modified while live.
This feature is too important and we will be moving to a SSD volume type instead to enable this feature. However it remains to be seen what restrictions we may have. Documentation states: “Current generation m3.medium instances fully support volume modification. However, some m3.large, m3.xlarge, and m3.2xlarge instances may not support all volume modification features.”
See more information at “Considerations for Modifying EBS Volumes”
Forum reference: https://forums.aws.amazon.com/message.jspa?messageID=771210