Chunk Offset address

Hi I am bit confuse on the Chunk offset address. I have a 9GB disk and have created 4 raw partitions of 2.01GB each. All these chunks 2GB each will be used for the same dbspace [datdbs]. The first chunk should have the offset 0 but what should be the offset address of second, third, and fourth chunks ? Should it be 0 or something else? I created using the following command: onspaces -a datdbs -p /dev/raw_links/data1 -o 0 -s 1024000 [Chunk1] onspaces -a datdbs -p /dev/raw_links/data2 -o 0 -s 1024000 [Chunk2] ... Shall be grateful on any comments. Thanks Muhammad Usman musman@iffco.com Sent via Deja.com http://www.deja.com/ Before you buy.

<musman@my-deja.com> wrote: > Hi > > I am bit confuse on the Chunk offset address. I have a 9GB disk and have > created 4 raw partitions of 2.01GB each. All these chunks 2GB each will > be used for the same dbspace [datdbs]. The first chunk should have the > offset 0 but what should be the offset address of second, third, and > fourth chunks ? Should it be 0 or something else? I created using the > following command: > > onspaces -a datdbs -p /dev/raw_links/data1 -o 0 -s 1024000 [Chunk1] > onspaces -a datdbs -p /dev/raw_links/data2 -o 0 -s 1024000 [Chunk2] > ... You do not have to add offsets because each of your chunks is a whole partition. Only if you want to split 1 partition in multiple chunks the first chunk begins with offset 0, the second with offset 0 + size of chunk1 and so on. But have a look to the -s clause in your statements. AFAIK the size is to be given in KB not in blocks at this statement. 2 GB = 2097152 KB HTH Reinhard

What you've done is fine. You should be aware that some OSs (Solaris for example) reserve the first few pages on a disk for vtoc information and you should therefore use a small offset for the first chunk on adisk (if you didn't already do this when you sliced the disk). Neil musman@my-deja.com wrote in message <81iitt$1n9$1@nnrp1.deja.com>... >Hi > >I am bit confuse on the Chunk offset address. I have a 9GB disk and have >created 4 raw partitions of 2.01GB each. All these chunks 2GB each will >be used for the same dbspace [datdbs]. The first chunk should have the >offset 0 but what should be the offset address of second, third, and >fourth chunks ? Should it be 0 or something else? I created using the >following command: > >onspaces -a datdbs -p /dev/raw_links/data1 -o 0 -s 1024000 [Chunk1] >onspaces -a datdbs -p /dev/raw_links/data2 -o 0 -s 1024000 [Chunk2] >...> >Shall be grateful on any comments. > > >Thanks > >Muhammad Usman >musman@iffco.com > > >Sent via Deja.com http://www.deja.com/ >Before you buy.

musman@my-deja.com wrote: >Hi > >I am bit confuse on the Chunk offset address. I have a 9GB disk and have >created 4 raw partitions of 2.01GB each. All these chunks 2GB each will >be used for the same dbspace [datdbs]. The first chunk should have the >offset 0 but what should be the offset address of second, third, and >fourth chunks ? Should it be 0 or something else? I created using the >following command: > >onspaces -a datdbs -p /dev/raw_links/data1 -o 0 -s 1024000 [Chunk1] >onspaces -a datdbs -p /dev/raw_links/data2 -o 0 -s 1024000 [Chunk2] >...> >Shall be grateful on any comments. > The purpose of the offset is to avoid a problem with some operating systems way of handling raw logical volumes. On some OS the first part of each volume is used by the OS for OS-mirroring infor- mation, size, name etc. If you use an offset of 0, you risk using this space both for your dbspace and for the OS. An offset of a few pages should do the trick, check on the OS for how much would be correct. Remember to reduce the size parameter with whatever is used by offset (it adds them for thr total spece needed), and give the sizes in multiples of the page size (so a page size of 4k, means an offset in multiples of 4 ). Page sizes can be checked with onstat -d which show size and offset in pages (compare tothe size you know has been given to the rootdbs to calculate page size) ///F.E.Theodorsen Now if you wanted four chunks on ONE logical volume of 9 GB (ie. all on eg. /dev/raw_link/data_big) you could start playing with offsets of 4,4+2GB,4+4GB,4+6GB but is is probably better to avoid this kind of stuff if at all possible. Finn E. Theodorsen///theodor@inet.uni2.dk///AtCbM///Legend#219605 TEN: Durax. Homepage: http://www.theodor.suite.dk/index.htm All advertisments sent to the above address will be treated as requests for computer support, and charged accordingly. Sending these kind of messages equals an acceptance of these terms. The minimum fee is $500.