Re: raw devices - general questions

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 Hi Allen, the offset is entered in KB. Currently I think there is no need to use an additional offset for system informations. In earlier version of LVM's there it was neccessary to use a 10KB offset. If you want to use two 2-gig chunks, you should partition your disks using LVM or any other operating system command ( sth. like fdisk ). Afterwards you will get two raw-devices ( each of 2-gig ) with different device-names like "/dev/rdsk/c0d2s1" and "/dev/rdsk/c0d2s2" ( depends on your operating system ). Using these device-names there is no need to enter an additional offset, so you can enter 0KB. Bye Stefan stefan@weideneder.de