>Inter-zone traffic significantly contributes to the overall cost structure of a data streaming system. Although eliminating inter-zone traffic can reduce costs, it may adversely affect availability or performance.<p>>The latency of low-cost cloud object storage solutions is not on par with persistent block storage or local SSDs. To meet specific performance requirements, the use of persistent block storage or local SSDs is essential.<p>Meh this is mostly an AWS issue where you get billed per GB. The actual cost of 100G transport between data centers is dirt cheap and so are SSDs/Optane. You can also commit hot data to RAM and rely on machines in each zone having independent battery backup