Communicator 3000 MPE/iX Release 6.0 (Platform Software Release C.60.00) (30216-90269)

Chapter 10 217
Technical Articles
Transaction Manager
Commands to Expand
The VOLUTIL tool is enhanced to provide two new commands to
facilitate the expansion (or truncation after initial expansion) of the XM
system log file. They are as follows:
1. showsyslog <volset-name>
This command accepts a valid MPE volume set name and shows the
current size of the XM system log in sectors. For this to work
correctly, the master volume has to be mounted in MASTER state.
The default size is 52128 sectors allocated at volset creation time.
2. altersyslog <volset-name> <new size>
This command accepts the volume set name and the new size of XM
syslog for it in sectors. It cannot be less than 52128 sectors and
cannot be more than 2 GB. This is a very large upper limit but as
disk capacities are becoming more and more, one can go for a size of
about 100Mbytes. One caution is that LDEV 1 has limited reserved
space and you cannot expand the XM syslog beyond that. Also, the
two residual logs on the master also will be expanded to match the
size of the system log.
The downside of having a larger system log is that the XM
checkpoint process will have more data to write to disk at reaching
the end of each syslog half. This can have an effect on response time
to on-line users.
Actual Expansion
The actual expansion of the XM system log happens when user boots
the system next time. This is because the XM log files cannot be
expanded/truncated while in use.
During bootup, just after recovery of the system volset, the XM system
log file will be expanded and a message will be written onto the console.
Also, the two residual logs that reside on the master will be expanded to
match it.
For the user volume sets, right after the recovery of system
transactions, the expansion of the system log happens.
You can also truncate the system log after expansion if there are any
disk space or performance issues. The VOLUTIL interface is same for
this operation too.
The residual logs will not be expanded until they are emptied, that is,
until all the members of the given volume set are mounted in the
MEMBER state.