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Which ASM Device is Which?

November 22, 2011

Did you happen to forget which raw device contains which Oracle ASM disk… perhaps you’ve reinstalled Oracle, or had a recent recovery event and lost your configuration. There may be an easy way to do this with an oracle script, but I’m not really a DBA. The ASM disk name is contained in the disk label, from the 136th byte (0x88) and terminated by NULL.

* asm-diskname.c
* Revision 1.0 19/11/2011 solidola
* Initial revision

#include <stdio.h>
#include <fcntl.h>

int main (int argc, char **argv) {
  unsigned fp;
  char buffer[512];
  char diskname[20]="";
  int a,i;
  int offset = 0x88;
  /* the asm disk name seems to start at 0x88 and is
  terminated by NULL */

  fp = open(argv[1], O_RDONLY);
  if (fp == NULL ) {
    printf("Unable to open %s", argv[1]);
    return (1);

  if (read(fp, buffer,512) 0 )
  diskname[i]=buffer[offset + i++];


  return (0);

From → SysAdmin

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