Re: Row Devices and Chunk offset

Apropos offsets. I'm using 20 k on my Altos Sco 3.2.4.2 machine. Anyone know what it SHOULD be? Yours, Nick ********************************* Nick Nobbe, Library of Congress NLS/BPH mail: nnob@loc.gov ********************************* On Thu, 23 Oct 1997, David Williams wrote: } In article <344CE734.46A7@bloomberg.com>, "Art S. Kagel" } <kagel@bloomberg.com> writes } >Omni Hotels Reservation Center wrote: } >> } >> Phillipe, } >> I can confirm this. We run AIX and when we initially set up we had to use } >> the same offset. The information came from the Informix engineer who } >> helped us configure. However, I have not seen documentation to back up } >> what she said. Since the configuration has never caused a problem, I have } >> always used the offset since. } >> Dave Thacker } >> Omni Hotels Reservation Center } >> } >> Philippe Meylan <Meylan@steria.ch> wrote in article } >> <622h0a$1sa@cssun.mathcs.emory.edu>... } >> > We are using INFORMIX 7.1x and our chunks are located on row devices. IBM } >> } >> > inform us that an offset of 512 bytes is required between the base of the } >> } >> > row device and the beginning of the chunk. This area should be used by } >> AIX } >> > for system management. } >> > } >> > My question : } >> > } >> > This requirement is undocumented and the ONINIT tools doesn't reserve any } >> } >> > offset when creating a new chunk. It's this requirement justified and can } >> } >> > be applied on any platform ? Has Informix a document explaining that } > } >The requirement is sstem dependent and actually probably unneccessary } >unless the device is also being used for filesystems at other offsets or } >is part of a software stripe set. Other OS's make similar requirements, } >on Ultrix it was the last 2K of the drive/device unless the drive was on } >a stripe set then the first 2K was also forbidden. Informix cannot } >keep track of all of the vendors' various ideosycroses (SP?). } > } >Art S. Kagel } } Solaris 2.5.1 it is the first 8K EVEN IF IT IS ONLY BEING USED AS A } RAW DEVICE. The VTOC on the front MUST be valid or else Solaris 2.5.1 } CANNOT access it at all! } } Solaris 2.4 it was the first 4K of the drive so the required value can } change with not just the OS but also the RELEASE of the OS. } } -- } David Williams }