Sentinel or OnLine mirroring - which?

We are having a heated debate on what replication to go for, Sentinel or Informix OnLine. We plan to purchase 2 x ALR Quad6 systems with Raid 5 built in, SCO OpenServer 5, Informix OnLine installed accessing some raw devices, but using Sentinel to mirror to a standby system in another building over 10BaseT (or Optical Fibre if really required). Although the systems will be used primarily for Informix apps I would like to store some DOS databases on the servers accessed by PCs through NFS. These databases I would also like to be replicated continuously rather than relying on a tape backup which might be 12 hours out of date. If we used the OnLine mirroring (High Availability Data Replication, HDR) this would only cater for the transfer of the Informix log files I presume. I should appreciate users of Sentinel or OnLine (or 1776) replying on how they run full redundancy over a network between a Primary Server and a standby Secondary Server under SCO OpenServer for ALL data. Which is more successful or useful? Do the systems also have RAID 5 installed? My colleague is also worried about performance degredation by allowing non Informix files to be mirrored using Sentinel rather than just Informix files using OnLine. I want everything continually backed up between the two servers in different buildings if possible. This is cross-posted between comp.unix.sco.misc and comp.databases.informix. Thanks in advance for any advice. We need to be sure the technology all works before we purchase within the very near future. Is Sentinel a proven product or a buggy new one? Unfortunately newer products Sentinel-MRA or 1776-RNA are not yet available as stable released products. I already have reviews from London Weekend Television, William Morrison Supermarkets and others but require more assurance before making the plunge. Karl Ian Ransome ransome@sasa.gov.uk System Administrator / Network Manager: SCO UNIX, OpenVMS, SunOS, Cromix, Novell, PC-NFS, Windows, DOS. Scottish Agricultural Science Agency, Edinburgh, EH12 8NJ, Scotland.