Re: Filesystem blocksize for archive logs on AIX

From: David Roberts <>
Date: Fri, 25 Oct 2013 12:33:36 +0100
Message-ID: <>

This is probably tangential to your original question but might re-enforce your assumptions.
With the explicit mention of 512 and 4K block sizes I did wonder if Advanced format hard disks was confusing the issue here.

I'm from a UNIX background/era where 512 was the physical block size and 8K was the logical block size.

However satisfying myself the 4K is a legitimate block size on AIX then I would observe:

With the advent of Advanced format hard drives, Oracle has introduced a parameter to inform Oracle about the underlying block size (either 512 or 4K) of the disks on which the redo logs reside. No such parameter exists AFAIK for data files.

On that basis, I would suggest that you verify the underlying hard disk technology, if they are 4K based, then I would suggest that the file system be logically formatted in the same way, if as is more likely it is 512 based, then go with that.

My personal observation is that file system block size seems significant to oracle for the redo logs. On that basis I would tend to use the same block size for the archived logs as you have suggested.

As a final caveat, I've used the terms 4K and advanced format hard drives interchangeably. I'm not sure if that is correct or if only the 512 bios 4K physical SATA drives will be labeled 'Advanced format drives'. Again I'm uncertain as to if Oracle would consider 512 bios 4K physical SATA drives 512 or 4K drives for the purposes of setting up redo logs.


On Thu, Oct 24, 2013 at 6:02 PM, Rich Jesse <> wrote:

> Hey all,
> I'm configuring new DBs on a new AIX 7.1 box. Instead of cloning
> our current setup on AIX 5.3, I'm revisiting all options for both
> flexibility and performance.
> The docs
> ( and
> articles like 1507249.1 are great, but one item I can't find anywhere is a
> recommendation for a filesystem blocksize for the archive logs. 4K for
> datafiles, 512 for online redos and controlfile, but nothing for archives.
> 512 would seem to be the likely answer, but it's been too many years since
> my v7.3 DBA classes and I can't remember how the archiver does its IO
> (sorry, Joe!). The docs don't seem to have that answer, either.
> I'm also open to any other advice for AIX-specific setup that's not
> referenced in the above docs (e.g. JFS2 noatime/rbrw for $ORACLE_HOME?).
> If
> it makes a difference, we'll be using XIV for storage. Seriously looking
> forward to playing with that puppy... :D
> TIA!
> Rich
> --

Received on Fri Oct 25 2013 - 13:33:36 CEST

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