Mirroring continued

} >>Ellen K. Osinski wrote: } } >>: I can put in a plug for Informix mirroring. We have implemented mirroring } >>: on an HP9000/750. We had the primary go down due to repeated disk write } >>: failures and did not realize it for a day or two. Informix chugged merrily } >>: along quite happliy using the mirror completely transparent to the users. } } >>: Would hardware mirroring provide this transparency? } Tim Cargile wrote: } } GOOD News: her Informix mirroring "chugged merrily along" } } NOT SO GOOD NEWS: "did not realize it for a day or two" } } I think I'd be finding out why the mirror failure was not immediately seen. Our monitoring tools did not look for down chunks. That has since been added. Also, the engine had been running fine for a while and I was lulled into complacency. } Broken mirrors are bad luck and I wouldn't want to press my luck by having } one (glass or disk) around for any longer than necessary. } If it's important enough to mirror than it's probably important enough to } keep mirrored. } } One could probably make a case for a daemon that "greps" for particularly } important Online log messages and ensures that they are seen as soon and } as often as necessary. Jeesh some people are never satisfied! } } Would hardware mirroring provide this transparency? } } Hopefully. Maybe even COMPLETLY transparent - except for the bill. I still do not understand how. It is my understanding that in using raw disks that Informix bypasses the OS and accesses the disk directly. If the disk goes down and hardware/OS mirroring kicks in, how is this transparent to either On-Line or the user when Informix wants to access a certain disk that is no longer alive? Inquiring minds want to know. Until then, I will rely on Informix mirroring because I KNOW it works. } } (They are working on self-healing systems - self billing too?) } __ | | | | ___________________________________________________________ | \\ | | | \\ | Ellen K. Osinski | | | | Hewlett-Packard | \\ \\ | Disk Memory Division - Information Systems | / \\ | 11413 Chinden Blvd | | ---/\\ | Boise, ID 83714-1023 | | | | | | | | phone : (208) 396-4904 | | * | | e-mail: ellen@hpbs2571.boi.hp.com | | | | telnet: 1-396-4904 | |___________| |___________________________________________________________|