Create Volume operation at Cloud [1.5.1]/Library/Integrations/Amazon/EC2/Elastic Block Store/Volumes/ does not allow specifying both a volume size and snapshotId and requires only one or the other. This is an unnecessary restriction. The current version of the AWS API (2015-04-15) does not have this limitation – a volume size greater than the snapshot size can be specified, creating a volume with a greater size than the snapshot it is based on.
There should be no limitation on specifying both a volume size and a snapshotId - an error should only occur if the volume size is smaller than the snapshot's size. When following Amazon's recommended approach to increasing the size of the volume, a critical step in this process is the creation of a new volume using a snapshot of the volume you wish to increase while also specifying a larger volume size. This allows for the creation of a new volume identical to the old one except with a larger volume size. In this operation's current state, the Create Volume operation cannot be used in this manner making it impossible to use in the above approach when increasing the size of a volume.
Enhancement request QCCR8C28708 Create Volume operation does not allow using both size and snapshotID for inputs has been submitted for this issue. Please see https://softwaresupport.hp.com/group/softwaresupport/search-result/-/facetsearch/document/KM01797540