Apologies if this has been answered previously, but I'm unable to find anything that seems to cover this.
It's clear that datanodes require local storage for Hadoop to function efficiently, but is there any significant disadvantage to using external storage for namenodes? We're exploring the possibility of using a different class of hardware for our namenodes with attached storage and little or no internal storage. Some of the benefits this would provide us are: 1) allowing our sysadmins to deploy hardware that they're familiar with and already have considerable experience keeping up in a production environment. 2) no namenode downtime to replace a failed disk. We don't anticipate that this approach would cause any significant degradation to performance, but let me know if there's something we're not considering. Thanks. Jonathan
