Re: HELP - Hardware mirroring versus dbms mirroring

On Wed, 17 Aug 1994, Will Hartung - Master Rallyeist wrote: } } }From: ckipp@vth1.vth.colostate.edu (Cathy Kipp) } } } }Not to disagree with an expert, but I think it's important to mention here that } } }while hardware mirroring may be faster with the OnLine engine, under the 6.0 } } }DSA engine, Informix miroring will offer some performance advantages. } } } } I haven't been controversial for a while, so why not now... } } } } Jon Bentley (or someone like him) said somewhere words to the effect that } } 'if you can simulate something in the language faster than the compiler } } does the same operation, the compiler writer has blown it badly'. } } } } I think much the same applies to disk mirroring -- if the O/S can't do it } } better than OnLine, then the O/S mirroring is probably defective. } } } } Yours, } } Jonathan Leffler (johnl@informix.com) #include <disclaimer.h> } } Yes, but I think Cathy is refering to the fact/rumor that 6.0 will be } able to READ from the mirror (i.e. poor mans striping), so that } extra rotating heater you've got bolted into your computer is a little } more functional than a fire extinguisher. Yes it will. My understanding is that OnLine will perform alternating reads between primary and mirror chunks, thus reducing amt of i/o to a single chunk. Jon ===================================================================== Jon C. Vemo Internet: jvemo@connected.com Bothell, WA USA ===================================================================== } } Will } (villy@collinscomp.com) }