Re: Raw disk sections

David Williams wrote: > > In article <329856AE.7A76@netcomuk.co.uk>, Neil Truby > <ntruby@netcomuk.co.uk> writes > >I've learnt a lesson over the weekend! > > > >I'm running OnLine v7.13 on a Sun Sparc20; Solaris 2.4. I have a 4 > >GByte disk which was split into two; the first slice was an Informix raw > >slice; the second a file system. The Informix raw slice began at > >cylinder 0. This seemed to cause problems on re-boot in that Solaris > >couldn't read the partition table for the disk. When I reversed the > >slicing so that the file system was first and the informix slice second, > >it came up OK. > > > >Is there are known problem with setting an informix slice at the > >begining of a disk? Does everyone else but me know this? Is it a case > Yes, and Er No thats why other people get problems as well! > > >of RTFM? I'm sure this wasn't a problem at my last site, on NCRs. > > > Yes - INFORMIX-Online Dynamic Server Administrator's Guide, Volume 1 > Page 15-6. THe first reason given is > > "To prevent OnLine from overwriting the UNIX partition information." > > "Many UNIX systems and some disk-drive manufactures keep information > for a physical disk drive on the drive itself. This information is > sometimes referred to as a volume table of contents (VTOC) or disk > label. (For the sake of convenience, it will be referred to here as > the VTOC.) The VTOC is commonly stored on the first track of the > drive. A table of alternative sectors and bad-sector mappings (also > called revectoring table) might also be stored on the first track. > For Sun Solaris, use the command "prtvtoc" to calculate the size of a track and always skip the first track. I have been following this approach to configure raw disk and never have problem (after I learn the above problem hard way). Chao