Understanding Oracle ACFS I/O Failure Console Messages

Oracle ACFS logs information for I/O failures in the operating-specific system event log.

A console message has the following format:

[Oracle ACFS]: I/O failure (error_code) with device device_name during a operation_name op_type.
file_entry_num Starting offset: offset. Length of data transfer: io_length bytes.
Impact: acfs_type   Object: object_type   Oper.Context: operation_context 
Snapshot?: yes_or_no AcfsObjectID: acfs_object_id . Internal ACFS Location: code_location.

The italicized variables in the console message syntax correspond to the following:

  • I/O failure

    The operating system-specific error code, in Hex, seen by Oracle ACFS for a failed I/O. This may indicate a hardware problem, or it might indicate a failure to initiate the I/O for some other reason.

  • Device

    The device involved, usually the ADVM device file, but under some circumstances it might be a string indicating the device minor number

  • Operation name

    The kind of operation involved:

    user data, metadata, or paging

  • Operation type

    The type of operation involved:

    synch read, synch write, asynch read, or asynch write

  • File entry number

    The Oracle ACFS File entry number of the file system object involved, as a decimal number. The acfsutil info fileid tool finds the corresponding file name.

  • Offset

    The disk offset of the I/O, as a decimal number.

  • Length of I/O

    The length of the I/O in bytes, as decimal number.

  • File system object impacted

    An indication that the file system object involved is either node-local, or is a resource accessed clusterwide. For example:

    Node or Cluster

  • Type of object impacted

    A string indicating the kind of file system object involved, when possible. For example:

    Unknown, User Dir., User Symlink, User File, Sys.Dir, Sys.File, or MetaData

    • Sys.Dir.

      Oracle ACFS-administered directory within the visible namespace

    • sys.File

      Oracle ACFS-administered file within the visible namespace

    • MetaData

      Oracle ACFS-administered resources outside of the visible namespace

  • Operational context

    A higher-level view of what code context was issuing the I/O. This is for use by Oracle Support Services. For example:

    Unknown, Read, Write, Grow, Shrink, Commit, or Recovery

  • Snapshot

    An indication of whether, if possible to determine, the data involved was from a Snapshot. For example:

    Yes, No, or ?

  • Object type of the file system

    An internal identifier for the type of file system object. For use by Oracle Support Services.

  • Location of the code

    An internal identifier of the code location issuing this message. For use by Oracle Support Services.

The following is an example from /var/log/messages in a Linux environment:

[Oracle ACFS]: I/O failure (0xc0000001) with device /dev/sdb during a metadata synch write .
Fenum Unknown. Starting offset: 67113984. Length of data transfer: 2560 bytes.
Impact: Node   Object: MetaData   Oper.Context: Write
Snapshot?: ?  AcfsObjectID: 8  . Internal ACFS Location: 5 .