Re: Parallel Database Solutions

Hi Jeff, At 08:14 01/07/97 -0600, Jeff Craig wrote: >Hmmm...I thought Informix XPS (eXtended Parallel Server) was an RDBMS >product built on "coservers" that could access data either on a given >"local" server or on a "coserver". That kind of fits into Jeff's >number one question. Maybe Jeff is looking for a fail-over system, in >which case there may be some type of "fail safe" system that lets a >secondary server "impersonate" the primary server in event of failure, >assuming its ip address and disks, including database. Well, maybe my answer was a little glib. I was working from the presumption that he was asking about two instances of ODS accessing the same disk storage simultaneously. XPS does not do this, XPS consists of a group of coservers, each of which is a separate OnLine instance. XPS allows one to treat this pool of coservers as one large server, in many ways. However, if a coserver needs to access data 'owned' by another coserver, it must pass the request via the owning coserver. It cannot access the other coservers disk storage directly. If a failover solution is required whereby a second system/ OnLine server takes over when one fails via dual ported disks then this too can be accomodated as long as both instances are never active at the same time (and have identical configurations). Chris ===================================================================== Chris Jenkins Senior Engineer, Northern Europe Advanced Technology Group Informix Software European Headquarters Informix House, Littleton Road, Ashford, Middlesex, TW15 1TZ, ENGLAND Tel: +44 1784 422066 (Direct) +44 468 574419 (Mobile) Fax: +44 1784 422069 E-mail: chrisj@informix.com =====================================================================