Mirroring question
Hi I don't understand the relation between Solaris disk mirroring and Informix mirroring. Can someone please explain? For example, what would be to impact of running Informix on a Solaris platform that is equipped with mirrored disks without implementing mirrored db spaces? In such an installation, would the effect of Solaris disk mirroring be different on dbspaces implemented in raw space vs cooked space? Would Informix function propely (without corruption) with all possible states of the Solaris mirrored disk pair? Thanks Alain Grumelart Ing. Systems Integration & IT Invensys Process Systems Foxboro Canada Inc.
Grumelart, .... wrote > > > Hi > > I don't understand the relation between > Solaris disk mirroring and Informix mirroring. > > Can someone please explain? > > For example, what would be to impact of running Informix > on a Solaris platform that is equipped with mirrored > disks without implementing mirrored db spaces? > > In such an installation, would the effect of Solaris disk mirroring > be different on dbspaces implemented in raw space vs cooked space? > > Would Informix function propely (without corruption) with all > possible states of the Solaris mirrored disk pair? > Disk mirroring on the OS / hardware should not be seen by Informix at all. I would say that hardware mirroring is most efficient and the best to use if you can afford the iron. Presumably using Solaris to mirror will have an impact, and whether it is more efficient than Informix mirroring I could not guess. Informix mirroring tends to come for free and that can be a consideration :-) BUT, I say you should always set Informix mirroring to 1, even if not used, because it allows you to swap chunks out without taking the engine down. A very impressive feat indeed when you are after 7/24 availability. Colin Bull c.bull@VideoNetworks.com
"Grumelart, ...." wrote: > > Hi > > I don't understand the relation between > Solaris disk mirroring and Informix mirroring. > > Can someone please explain? By Solaris disk mirroring I assume you mean DiskSuite or whatever it's called these days. Disksuite is a software based volume manager, capable of doing much the same as Veritas at a fraction of the cost. It includes mirroring, striping and RAID5 - it also adds transactions to UFS though this is not of any interest to Informix Informix mirroring allows you to keep two copies of a dbspace - it has no understanding of the underlying disk system. > > For example, what would be to impact of running Informix > on a Solaris platform that is equipped with mirrored > disks without implementing mirrored db spaces? There is no impact - well not really - OS LVM is usually marginally quicker than Informix - all things being equal. > In such an installation, would the effect of Solaris disk mirroring > be different on dbspaces implemented in raw space vs cooked space? No, how you mirror is not directly related to what you mirror > > Would Informix function propely (without corruption) with all > possible states of the Solaris mirrored disk pair? It will not be corrupted (assuming no RAID5) although it might not still function depending on how many disks have failed. > > Thanks > > Alain Grumelart Ing. > Systems Integration & IT > Invensys Process Systems > Foxboro Canada Inc. -- Paul Watson # Oninit Ltd # Growing old is mandatory Tel: +44 1436 672201 # Growing up is optional Fax: +44 1436 678693 # Mob: +44 7818 003457 # www.oninit.com #