Thank you for the clarification Daniel. That is what I suspected. -----Original Message----- From: Daniel Maher [mailto:dma+gluster@xxxxxxxxx] Sent: 18 February 2009 09:41 To: Chris Mavin Cc: gluster-devel@xxxxxxxxxx Subject: Re: Glusterfs HA & AFR Chris Mavin wrote: > Can someone clarify the following for me. > > I'm using Glusterfs RC 2. > > If I am using the HA translator rather than AFR, Does this expect to be > using a shared storage accessible from both servers? > > Put another way, is the HA translator simply a way of providing High > availability for a SAN? > > When I test it using 2 servers the active server is written to fine but > the backup server simply gets a 0 byte file written to it. HA is, afaik, just a way to switch communications between target machines - it does not itself have any sort of replication features, nor does it have the ability to speak to multiple targets simultaneously. Given three machines : - ClientA - ServerA - ServerB If ClientA is configured to communicate to ServerA & ServerB via HA, it will pick one (ServerA, for example), and speak to it exclusively until such a time as ServerA stops working - whereupon it will communicate with ServerB. Nowhere in that scenario is data replicated or copied between ServerA and ServerB. For this, you'd either need to set up server-side AFR between ServerA and ServerB (and keep HA on ClientA), or set up client-sde AFR on ClientA (and ditch HA altogether). -- Daniel Maher <dma+gluster AT witbe DOT net>
