Re: Problem in installing raw device for oracle

In article 732297434_at_carioca, zhou_at_igd.fhg.de (Zhou Jian) writes:
>Dear netters,
>
>It is said that using raw device can speed up oracle access
>to the database, so I formatted a patition on a disk as raw device and
>installed the oracle. At the beginning it works well. However,
>after several test tables are created, the oracle
>processes are terminated abnormally. When I try to restart
>oracle, I get the error message which says that oracle
>cannot access the raw device. The "format" utility
>shows me that the drive type became unknown:
>
>AVAILABLE DISK SELECTIONS:
> 0. sd0 at esp0 slave 24
> sd0: <SUN0424 cyl 1151 alt 2 hd 9 sec 80>
> 1. sd1 at esp0 slave 8
> sd1: <Fujitsu M2654SA cyl 2194 alt 3 hd 21 sec 87>
> 2. sd3 at esp0 slave 0
> sd3: <drive type unknown>
>
>I use one patition on sd3 as raw device. The error can be repeated.
>I think I have made some obvious mistakes but cannot find any
>hints from SunOS and Oracle manules. I am using SunOS 4.1.3 on a Sparc
>10 with ORACLE RDBMS V6.0.33.1.1.

I've seen a similar problem using raw devices with Sybase. If you've used the entire disk in your single partition, then the section which holds the disk information will be overwritten/corrupted by your data. I guess this disk-label corruption may have contributed to your processes bombing out.

 What you should have done is format the disk to have one partition (eg sd3a) which starts at block 0 and is 1 cylinder long - I think it's only the first track that you need to 'protect', but allocating 1 cylinder makes the sums easier ! Then define another partition starting at cylinder 1/0/0 with size of 'total cylinders - 1' ie size of sd3c - 1. Then use this partition as your raw device and ignore sd3a. All other partitions (except sd3c) should have size of 0.

 From memory (so no guarantees !) you _should_ be able to get your disk information back by going into format, select disk 2 (ie sd3), and then go into partition option, and then use select to choose a predefined 'table'. Then choose the label option. Format should then recognise the disk type, and you can go back in an re-partition the disk as described above.

Hope this helps !

Davina

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| Davina Gray                           Sun Microsystems Scotland BV    |
| davina.gray_at_uk.sun.com        Linlithgow                                  |
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