The messages in this chapter are generated by the Direct Bulk
I/O Support Procedures (DBIOPROC) subsystem. The subsystem ID displayed
by these messages includes DBIO as the subsystem name.
DBIOPROC is one of several subsystems that work together to
provide Direct Bulk I/O to enhance system performance. With Direct
Bulk I/O, which is transparent to applications, disk and tape bulk
data is transferred directly over ServerNet between an application
data buffer, in any processor, and a storage controller under direction
from the controlling input/output process (IOP) in the same or a different
processor. Otherwise, with normal I/O, application data always flows
through an intermediate buffer in the processor of the controlling
IOP.
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 | NOTE: Negative-numbered messages are common to most subsystems. If
you receive a negative-numbered message that is not described in this
chapter, see Chapter 15. |
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| 1 Error return code received. |
Cause The return code received is not as expected; usually a value
of zero is expected. Effect An error is returned to the client file system, typically resulting
in recovery by ending the Direct Bulk I/O session and reverting to
normal I/O. Recovery This event should be extremely rare; any occurrence indicates
that the Global NonStop Solution Center (GNSC) should be notified
even though no service action is required for recovery. Frequent occurrence
of this event might suggest that Direct Bulk I/O should be disabled
via Subsystem Control Facility (SCF) in order to minimize system performance
impact.. |
| 2 HW checksum error fixed by SW. |
Cause The S7000 checksumming hardware implementation can produce an
incorrect checksum under certain rare conditions. An extra check is
made to detect this case. Effect None. Recovery This event should be rare; infrequent occurrence should not
require any service action. However, frequent occurrence of this event
indicates that Global NonStop Solution Center (GNSC) should be notified
and might suggest that Direct Bulk I/O should be disabled via SCF
in order to minimize system performance impact. |
| 3 SvNet addresses quarantine start. |
Cause Either an input/output process (IOP) or a client file system
indicated that quarantining was needed. Effect The quarantined ServerNet addresses are not used during the
quarantine time period. Buffers are re-mapped as necessary so that
I/O continues without significant interruption. Recovery This is an informational message; no recovery action is needed. |
| 4 SvNet addresses quarantine end. |
Cause The quarantine time period has elapsed. Effect The specific set of previously quarantined ServerNet virtual
addresses are available for reallocation. Recovery This is an informational message only; no recovery action is
needed. |
| 5 Sector checksum error. |
Cause The data read from disk into the application buffer is inconsistent
with the corresponding sector checksum read from disk. Effect An error is returned to the client of the DBIOPROC, typically
resulting in recovery by the client file system by ending the Direct
Bulk I/O session and reverting to a normal I/O. Recovery Infrequent occurrence of this event does not need a recovery
action. If the underlying cause persists, an error is likely to occur
during normal I/O and can result in a more detailed error event generated
by the input/output process (IOP). Frequent occurrence of this event
without corresponding IOP-generated error events could indicate an
improperly written application that affects its data buffer during
a nowaited I/O operation using the same buffer and might suggest that
Direct Bulk I/O should be disabled via SCF until the application problem
is resolved. |
| 6 Structured checksum error. |
Cause The data read from the disk into the application buffer is inconsistent
with the expected overall checksum value of zero for structured blocks. Effect An error is returned to the client of the DBIOPROC, typically
resulting in recovery by the client file system by ending the Direct
Bulk I/O session and reverting to a normal I/O. Recovery Infrequent occurrence of this event does not need a recovery
action. If the underlying cause persists, an error is likely to occur
during normal I/O and can result in a more detailed error event generated
by the input/output process (IOP). Frequent occurrence of this event
without corresponding IOP-generated error events could indicate an
improperly written application that affects its data buffer during
a nowaited I/O operation using the same buffer and might suggest that
Direct Bulk I/O should be disabled via SCF until the application problem
is resolved. |
| 7 Structured RSN not as expected. |
Cause The client file system detected the error and provided expected
and actual RSN values to be logged in an event. Effect The client file system typically recovers by ending the Direct
Bulk I/O session and reverting to a normal I/O. Recovery Infrequent occurrence of this event does not need a recovery
action. If the underlying cause persists, an error is likely to occur
during normal I/O and can result in a more detailed error event generated
by an input/output process (IOP). Frequent occurrence of this event
without corresponding IOP-generated error events could indicate an
improperly written application that affects its data buffer during
a nowaited I/O operation using the same buffer and might suggest that
Direct Bulk I/O should be disabled via SCF until the application problem
is resolved. |