Hi there, I don’h have experience using jgroups over s3 but a minute seems really long. When jgroups is used on a local network it’s instantaneous, there delay is so small that it’s unnoticeable. "Are there any recommendations on how to speed up cache-sync time between XWiki hosts on a cluster?” Not much can be doe on the xwiki side here. I think the best bet would be to ask on the jgroups mailing lists to see if anyone has experience of jgroups over s3. "Also, in a cluster, is the default XWiki cache a distributed cache?” This is what xwiki is implementing! each instance has a cache and they sync through jgroups, making it a distributed cache. The only idea I have would be to modify the mechanism somehow so that: * when the page is saved, jgroups is configured to block till all cluster members have received the message * this could also be implemented by having all members returning another ack message to the  sender, and the sender would wait for these messages before exiting the save. However in your case this would mean that any save would take more than 1 minutes (probably 2+ seen the communication tile you are currently experiencing). Thus it won’t be a solution. You really need to find what’s taking long. "Or is the same cache content replicated across all nodes in a cluster? “ see http://extensions.xwiki.org/xwiki/bin/view/Extension/Observation+Module+Rem… no content is transmitted over the network. Only the doc reference so that each instance evicts it from its memory cache so that next time the doc is asked it’s fetched from the DB. Hope it helps, -Vinent Massol On 8 May 2015 at 03:57:58, Debajit Adhikary (debajit(a)outlook.com) wrote: We have deployed XWiki over a two-node EC2 cluster. We are using JGroups over S3 for cluster messaging as multicast does not work in EC2. I have noticed that if I edit a page on host A, and then refresh the same page from host B, it shows stale content — it takes up to a minute for the caches to sync. Is this something others have observed when running XWiki over multiple hosts? (I'm wondering if this is a JGroups/S3 issue)For people who are running XWiki in a cluster, how long does it typically take for changes made from one machine to show up in another?Are there any recommendations on how to speed up cache-sync time between XWiki hosts on a cluster? Also, in a cluster, is the default XWiki cache a distributed cache? Or is the same cache content replicated across all nodes in a cluster?