Technical data

System Management Release Notes
5.14 RMS Journaling
Previous versions: [SYSJNL]RMS$214003BC.RMS$JOURNAL;1
Current version: [SYSJNL.NODE1]CB300412.;1
If RMS does not find either the [SYSJNL] directory or the node-specific directory,
RMS creates them automatically.
5.14.2 Recovery Unit Journaling Incompatible with Kernel Threads (Alpha
Only)
V7.3
Because DECdtm Services is not supported in a multiple kernel threads
environment and RMS recovery unit journaling relies on DECdtm Services,
RMS recovery unit journaling is not supported in a process with multiple kernel
threads enabled.
5.14.3 After-Image (AI) Journaling
V6.0
You can use after-image (AI) journaling to recover a data file that becomes
unusable or inaccessible. AI recovery uses the AI journal file to roll forward a
backup copy of the data file to produce a new copy of the data file at the point of
failure.
In the case of either a process deletion or system crash, an update can be written
to the AI journal file, but not make it to the data file. If only AI journaling
is in use, the data file and journal are not automatically made consistent. If
additional updates are made to the data file and are recorded in the AI journal, a
subsequent roll forward operation could produce an inconsistent data file.
If you use Recovery Unit (RU) journaling with AI journaling, the automatic
transaction recovery restores consistency between the AI journal and the
data file.
Under some circumstances, an application that uses only AI journaling can
take proactive measures to guard against data inconsistencies after process
deletions or system crashes. For example, a manual roll forward of AI-journaled
files ensures consistency after a system crash involving either an unshared AI
application (single accessor) or a shared AI application executing on a standalone
system.
However, in a shared AI application, there may be nothing to prevent further
operations from being executed against a data file that is out of synchronization
with the AI journal file after a process deletion or system crash in a cluster.
Under these circumstances, consistency among the data files and the AI journal
file can be provided by using a combination of AI and RU journaling.
5.14.4 Remote Access of Recovery Unit Journaled Files in an OSI
Environment
V6.1
OSI nodes that host recovery unit journaled files that are to be accessed remotely
from other nodes in the network must define SYS$NODE to be a Phase IV-style
node name. The node name specified by SYS$NODE must be known to any
remote node attempting to access the recovery unit journaled files on the host
node. It must also be sufficiently unique for the remote node to use this node
name to establish a DECnet connection to the host node. This restriction applies
System Management Release Notes 5–29