Re: Mirroring HW vs Informix - follow up

> We recently had an incident and here are some insights gained therefrom. > > We have mixed HW and Informix mirroring depending on who set up what engine. > A recent incident trashed several of the our raw disks. The HW mirroring > faithfully replicated the trash across the mirror. The Informix mirroring > did not. > > We are switching to Informix mirroring. > > cheers > j. Jack, I would suggest that you check what hardware you are using. Normally in hardware mirroring the same block of data is sent by the disk controller board to both disks separately. This avoids the possibility of a block being written and corrupted and then written to the mirror. Informix mirroring is one step further of abstraction in that it sends two separate pages to the disk controller to write to the primary and the mirror separately. This is why hardware mirroring is generally faster. Your description suggests that you may have a problem with your disk controller rather than or as well as the drives. To have a corruption written to both the primary and mirror suggests the possibility that the corruption occured before the block left the disk controller. Cheers - Jim My opinions are my own. They may vary with time but they remain MINE! ---------------------------------------------------------------------- Name: Jim Gordon Internet: jgordon@ssf-sys.DHL.COM Company: DHL Systems Inc Phone: (415) 375-5222 (Work) Address: 700 Airport Blvd. #300 (415) 775-7762 (Home) Burlingame, CA 94010-1937 Fax: (415) 375-5019 ----------------------------------------------------------------------