In the whitepaper mentioned below, Under 'Limitations' it says ASM and fan based notifications are not supported by IPv6 in Oracle. I'm just curious what ASM has to do with ipv4 or ipv6 or ipv4? ASM is just a file system. http://www.oracle.com/technetwork/database/enterprise-edition/oracledatabaseipv6sod-2141330.pdf

  • I think this is a misinterpretation. It is not ASM who doesn't support ipv6 (I'm sure I can use ASM in a networkless system). It's Oracle Restart and FAN who doesn't support it (and therefore, the ASM management with Oracle Restart). Question is why it specify ASM with Oracle Restart and don't just say Oracle Restart? Maybe Oracle Restart doesn't make a difference with ASM whenever the ASM instance is in the same server or in a different one,. But it does with database instances? That's what seems odd to me. I don't get it.
    – vegatripy
    Commented Jul 13, 2015 at 13:11

1 Answer 1


ASM isn't just a file system. It's also a volume manager.

An ASM instance is a cut-down Oracle instance that database instances talk to in order to find out how to access the blocks they need. The ASM instance doesn't write data to or read data from the disks itself, it only provides the information that the database requires in order to do this.

This communication is over the network, so involves IP. Hence the note about IPv4/IPv6.

  • I'm not sure about your statement. The whole point of ASM is to avoid the system to make I/O calls and also serve as a volume manager. But communication between different ASM instances its Clusterware's thing (which is ipv6 limited). AFAIK, ASM does directly read/write data from disk
    – vegatripy
    Commented Jul 13, 2015 at 12:59
  • Have a look at docs.oracle.com/cd/E11882_01/server.112/e18951/… (About Oracle ASM Instances). The key sentence is "Oracle ASM instances manage the metadata of the disk group and provide file layout information to the database instances" Commented Jul 13, 2015 at 15:14
  • Also here: docs.oracle.com/cd/E11882_01/server.112/e40540/… (Oracle ASM Instances): "Database instances direct I/O to ASM disks without going through an ASM instance" Commented Jul 13, 2015 at 16:10

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