The namenode uses storage to write file system transaction logs as well as to write server-debug-log-messages. Both of these could be stored in a NFS mounted file system, should work well.
thanks, dhruba On Wed, Oct 21, 2009 at 9:15 AM, Jonathan Seidman < [email protected]> wrote: > 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 > -- Connect to me at http://www.facebook.com/dhruba
