Re: raw devices - general questions

allenj@ndr.com (Allen Jantzen) wrote: >I have 2 4-gig SCSI drives (one for a primary, one for a mirror) that >I want to configure as raw devices for Informix 7.13UC1 - a data >warehouse. >A few questions: (please forgive if they are of a newbie nature) >what exactly is the offset that informix is asking for when I create >my dbspace and initial chunk? Is it in tracks? Is it the number of >tracks to skip before writing data OR the track number to start >writing at??? >I think the SCSI drive has a table of contents/VTOC at track 1, which >I obviously want to leave alone. Would my offset be 1 or 2?? >I was hoping to create two 2-gig chunks on the drive. Because >Informix has a 2-gig chunk limit, does this mean that it can't access >or "go past" the first chunk on the drive??? Will my second chunk be >available? If so, how do I calculate the offset for the 2nd chunk?? >Any help *greatly* appreciated. >Allen W. Jantzen >DBA >allenj@ndr.com The offset is in kbytes. Some hardwares do use the firxt x bytes for os stuff. We have found using an offset of 10 is good. I suggest you split the disk into 2 2gig logical volumes if possible and then each logical volume is treated as a seperate disk. I have seen problems when tring to give informix an address over 2 gig. It depends on the hardware and the level of informix. Hope this helps a little -- Tolly Brumbelow, Informix DBA email:tolly.brumbelow@bridge.bellsouth.com