I assume you're using ZFS filesystem for the transparant compression, what's your opninion/experience on using ZFS on cloud storage? I mean; the EBS disks are already redundantly stored by AWS and the COW mechanism could lead to a lot of write amplification; negatively impacting the network attached storage?

(I don't use EBS in my day job, but Azure's disk offering don't really offer adequate perforamance when used with any filesystem other then EXT4 in my experience)