questions and suggestions
1994-02-17 17:20:17
I have been testing adsm for about two weeks. Like Martha I am working with
the VM server and I am not a workstation expert. So I have a few questions and
maybe a few requests for changes of the IBM-adsm team. Which brings up another
question. Is there a group or person who collect share requirements for the
adsm product?
VM Server questions:
1) There are no timestamps on the messages in the server console log.
How many vote for timestamps?
2) There is a "set accounting on" command. I would assume that most
sites would normally want accounting on or off all the time.
Should this not be an option in the dsmserv opt file?
3) Should there be an option to write the accounting data to a
file instead of to cp accounting services. This would be for
sites that want the data for stats and not for charge back.
to an VM userid. After all, most of the clients would not have
an VM userid to have the chages applied against.
One could see the server saving the data to files stored within it's
own storage pools. On cms one could use dfsms to recall the data
when needed.
4) Can IBM-adsm document how the recovery log is used.
With the doc set that came with PN49454 there are instructions for
new data-base backup and restore procedures. As part of these
procedures it calls for:
4. Issue 3 CKPT commands so that database changes are flushed to
the database media.
5. Wait 30-60 seconds before halting the server with the HALT command.
I would have assumed that shutdown down and restarting the server would
have cleared the recovery log.
5) I was using tape mount exits to interface the dsmserv mount requests
with vmtape. This seems to work most of the time, but there are a few
gray areas with MOUNTWAIT and with a request to have the server
cancel a mount request.
On page 334 of the Administrator's Guide release 1 it is written
"The MOUNTWAIT value is not used by the server to automatically
cancel requests handled by exit machines. You can use the value in
the DSMMOUNT EXEC or ignore it, however you see fit."
On page 333
"4. If requested, the DSMMOUNT EXEC must cancel the tape mount.
...."
I am not sure how one could do the above when using the vmtape command
with the vmtape wait option.
It turns out that what really happens is that at the end of the
MOUNTWAIT period or when the cancel mount command is used, the
server issues the cp force command against the mount exit machine.
The first time I ran into this, the operators were not able to
find the proper tape within the 60 mins wait period. The server
issued the force command after waiting 60 mins.
This did not work since it had only been defined with a cp priv
class of G. When the operators did finish the mount, vmtape
attached the volume to dsmserv. dsmserv started using it. But as
soon as the exit machine started logging off, the dsmserv server
tried to autolog it and that failed since the exit machine was in
a logoff/force pending state. The logoff processed finished and
the server autologed the mount exit machine with a second scratch
request that was pending after it tried to cancel the first mount.
Since there was only one mount exit machine defined it could not
autolog another.
The good news is that the server knew what to do with both tapes
even after canceling the request for one of them.
The bad news, It can try to autolog an exit before cp completes the
logoff process. I believe that dsmserv needs a short delay between
seeing a mount exit machine logoff and the next autolog.
I know that the force/pending problem in CP is not quite what it used
to be, but I still bad feeling about the production use of force.
Would it be a viable options to have the dsmserv server autolog
another mount exit machine that could issue an vmtape cancel command?
But then maybe the autologing of another mount exit machine could
cause even more problems. Any good thoughts on this.
Should the mountwait period be settable by a site? In the config file
or by command or both?
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