Re: Large raw partitions > 2GB on Sequent platform

On Tue, 17 Dec 1996 15:11:11 -0600, ken_hartman_at_firstdata.com wrote:

>We are a Sequent site running DYNIX/ptx version 4.2.0. This verion
>supports files up to 1TB, but we can't seem to make certain sizes work.
>We have successfully created a 1, 2, 5, 6 and 13 GB partitions, but can't
>make 3, 4, and 8 GB. The Oracle errors states we don't have enough space
>on the device, but a dd of the raw partition proves otherwise. Our
>Sequent SE80 is connected to a StorageTek disk array system. Our initial
>database size will be around 700 GB, so we don't want to work with 2GB
>files. I'm also uncomfortable with the way Oracle is creating these.
>Their support is very poor on this subject, so I don't trust the
>partitions that are working. Anyone out there running DYNIX/ptx 4.2.0 that
>could lend us a hand. Thanks.
>
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Ken,

        You don't state which version of Oracle you are using, so I can't tell you if you have the same problem we had. First off, when declaring the size of the raw partition to Oracle, you need to subtract 2 x BlockSize otherwise Oracle doesn't think you have the correct space.

Secondly, we found that creating raw partitions greater than 2 GB simply didn't work. The problem for us was that Oracle uses the Unix lseek() function, which takes only a 32 bit offset. As this is a signed number (so you could logically seek backwards from where you are), you have 2 ^ 31 = 2GB. When we tried to go bigger, we managed the raw partition to Oracle, but then it only used the first 2 GB. Fine if you only have 2 GB of data, but beyond that you get page corruption.

You need a version of Oracle that support the 64 bt llseek() instruction. I'd check this very carefully with both Oracle and Sequent support before I put live data in to the database - once bitten, twice shy!

Adrian P Challinor
Osiris Consultants Ltd
Adrian.Challinor_at_osiris.co.uk Received on Tue Dec 31 1996 - 00:00:00 CST