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We run an AIX database server.

Our DB team is looking at this configuration:

  • hdisk6 to have a mount point of /u02/app/oradata/hisdb
  • hdisk7 to have a mount point of /u02/app/oradata/hisdb/rmirror

will the nested filesystem be the correct way to handle this? If so, how can this be done?

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migrated from Apr 7 '11 at 10:59

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We can't answer without knowing what you're trying to do, and what result you're expecting. – wazoox Apr 7 '11 at 11:03
up vote 3 down vote accepted

Not a problem, all file system are indirectly 'nested' off the / filesystem. Just make sure you mount the base hisdb filesystem before you mount rmirror (via the ordering in /etc/filesystems). However, it would be "cleaner" to mount completely separate off the root, if you ever need to umount the hisdb file system you'd need to umount rmirror first.

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A "nested" filesystem isn't the correct way to handle this (or more accurately, it's a funny term for the correct way to handle this).
A separate filesystem is what your Oracle admins are asking you to do:

  • Create a filesystem on hdisk6 mounted at /u02/app/oradata/hisdb
  • Create a filesystem on hdisk7 mounted at /u02/app/oradata/hisdb/rmirror

As HampusLi pointed out this means you must mount /u02/app/oradata/hisdb before you mount /u02/app/oradata/hisdb/rmirror, and unmount in the reverse order (which will be handled for you if you create the filesystems using smit or smitty)

What they're not saying explicitly is that hisdb and the hisdb/rmirror space should be on separate disk spindles - mostly for performance reasons - but it's implicit in the fact that the filesystems exist on two different disk devices.

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