| |
|
RSS Feed - WebSphere MQ Support
|
RSS Feed - Message Broker Support
|
| how to know why log is growing |
View previous topic :: View next topic |
| Author |
Message
|
| fjb_saper |
 Posted: Sun Mar 01, 2009 9:41 am Post subject: |
 |
|
Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
|
Bruce, I am thinking, what happens to the log if the messages, even though not persistent, are retrieved under explicit syncpoint? 
_________________
MQ & Broker admin |
|
| Back to top |
|
 |
| bruce2359 |
| Posted: Sun Mar 01, 2009 10:19 am Post subject: |
|
|
Poobah
Joined: 05 Jan 2008
Posts: 9471
Location: US: west coast, almost. Otherwise, enroute.
|
Logged messages and other things logged are not removed from logs. Logs are history. Logs are required for queue manager restart to ensure consistency. Non-persistent messages are not logged. UofW information is logged.
Linear logs become archivable when they no longer contain active UofWs or anything else needed for restart. Circular logs become overwrite-able when they no longer contain active UofWs or anything else needed for restart.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
|
| Back to top |
|
|
| sebastia |
| Posted: Sun Mar 01, 2009 12:24 pm Post subject: |
|
|
Grand Master
Joined: 07 Oct 2004
Posts: 1003
|
Yes, Bruce - thank you very much.
I did find that sentence in 10 minutes.
And the solution is ..... "dmpmqlog -b -m QMGRNAME"
The "-b" flag does the trick.
It lists who did put the message into the MQ system,
and the timestamp.
From that data, someone has to be able to tell the source of the problem.
Cheers ! |
|
| Back to top |
|
|
| zhanghz |
| Posted: Wed Mar 04, 2009 7:53 pm Post subject: |
|
|
Disciple
Joined: 17 Jun 2008
Posts: 186
|
on mainframe,
| Quote: |
What logs are
WebSphere MQ records all significant events as they occur in an active log. The log contains the information needed to recover:
Persistent messages
WebSphere MQ objects, such as queues
The WebSphere MQ queue manager
The active log comprises a collection of data sets (up to 31) which are used cyclically. |
| Quote: |
There are four types of log record, described under the following headings:
“Unit-of-recovery log records”
“Checkpoint records”
“Page set control records” on page 34
“CF structure backup records” on page 34 |
If the active log datasets are defined as per the example in SCSQPROC, the datasets are not expandable. So they will not increase in size.
Maybe the mainframe customer is refering to archive logs? Archive logs will grow in size for sure if they are defined on DASD.
And what's wrong with non-persistent messages? Most of messages are not required to be persistent. If all messages are persistent, big problem will arise when messages are stuck in the queues, which will most probably cause pagesets to be full.. |
|
| Back to top |
|
|
| sebastia |
| Posted: Wed Mar 04, 2009 11:24 pm Post subject: |
|
|
Grand Master
Joined: 07 Oct 2004
Posts: 1003
|
Well -
we know who writes the messages in the allways growing log : CICS.
It is a "classical" structure :
communications (MQ) module reads the request queue.
and depending on the origin,
starts one APPL or another,
that generate a response,
but all of them are under CICS,
so for the "sending" communications (or MQ) module,
it is just "CICS" that we find in the active LOG.
Any more ideas ?
Seb. |
|
| Back to top |
|
|
| sebastia |
| Posted: Wed Mar 04, 2009 11:30 pm Post subject: |
|
|
Grand Master
Joined: 07 Oct 2004
Posts: 1003
|
mr zhanghz :
The 4 items you refer to in your quote ...
are taken from what book ?
| Quote: |
“Unit-of-recovery log records”
“Checkpoint records”
“Page set control records” on page 34
“CF structure backup records” on page 34
|
??? |
|
| Back to top |
|
|
| fjb_saper |
| Posted: Thu Mar 05, 2009 4:15 am Post subject: |
|
|
Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
|
| sebastia wrote: |
Well -
we know who writes the messages in the allways growing log : CICS.
It is a "classical" structure :
communications (MQ) module reads the request queue.
and depending on the origin,
starts one APPL or another,
that generate a response,
but all of them are under CICS,
so for the "sending" communications (or MQ) module,
it is just "CICS" that we find in the active LOG.
Any more ideas ?
Seb. |
Normal. Refer to CICS transaction handling mode. You are writing to the UOW logs.
_________________
MQ & Broker admin |
|
| Back to top |
|
|
| zhanghz |
| Posted: Thu Mar 05, 2009 4:22 pm Post subject: |
|
|
Disciple
Joined: 17 Jun 2008
Posts: 186
|
| sebastia wrote: |
mr zhanghz :
The 4 items you refer to in your quote ...
are taken from what book ?
| Quote: |
“Unit-of-recovery log records”
“Checkpoint records”
“Page set control records” on page 34
“CF structure backup records” on page 34
|
??? |
GC34-6582-00, WebSphere MQ for z/OS Concepts and Planning Guide, Chapter 4. Logging |
|
| Back to top |
|
|
| sebastia |
| Posted: Fri Mar 06, 2009 11:20 am Post subject: |
|
|
Grand Master
Joined: 07 Oct 2004
Posts: 1003
|
mr zhanghz - thanks
Will tell the z/OS people to look into "their" books ... jejeje
mr Saper - UOW = unit of work, I guess.
So, if they are using MQ_Commit() quite frequently,
there is no solution for that (active) log size, am I right ?
If it were "persistent messages", I could tell then no to use them
but can't tell them to remove the commit(s) !
Thanks - shall print the log anyway.
Sebastian. |
|
| Back to top |
|
|
| bruce2359 |
| Posted: Fri Mar 06, 2009 2:45 pm Post subject: |
|
|
Poobah
Joined: 05 Jan 2008
Posts: 9471
Location: US: west coast, almost. Otherwise, enroute.
|
Back to the original post:
| Quote: |
I have a customer (MQ on z/OS) that complains :
a) messages are not persistent
b) log increases 8 GB every day (it is linear) |
I suspect that there are just short of 8gb of messages - meaning persistent messages - being logged.
Your z/OS WMQ support folks will need to print the WMQ z/OS logs to prove or disprove the theory that there are no persistent messages.
| Quote: |
So, if they are using MQ_Commit() quite frequently,
there is no solution for that (active) log size, am I right ? |
UofW data is pretty small. I doubt this is the cause of the 8gb log growth.
Only active logs are required for restart. Active logs contain state data about active UofWs. Once logs no longer contain active UofW data, they become inactive and archivable.
It is normal behavior for (the number of) logs to grow over time; and it is normal for active logs to become inactive.
In your post, you said that active logs are growing. Your z/OS WMQ support folks will need to print the BSDS log directory to determine which are active and which are inactive. They should enable the automatic archiving of inactive log datasets.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
|
| Back to top |
|
|
| sebastia |
| Posted: Sat Mar 07, 2009 1:42 am Post subject: |
|
|
Grand Master
Joined: 07 Oct 2004
Posts: 1003
|
I dont know the size of the "UoW" data being logged - if it is short, yes, it is dificult to fill up 8 GB of disk. I trust your word, of course.
Customer moves 3.000.000 messages a day, of 32 KB each (CICS COMAREA size), and the product is 300 GB if I am not wrong.
But 8 GB divided by 3.000.000 makes 2,6 KB - maybe the size of an "ACK" message ? (I think MQ headers add up to 1,5 KB more or less, am I right ?) So a 1 KB message will do the growing ...
I donk know how to diferentiate "active" logs at host from inactive and/or archivable. I know they use an IBM tool to scan the filesystem, and this produces that result. Bet it is a "standard" procedure, not their own.
Have a nice weekend. Seb. |
|
| Back to top |
|
|
| bruce2359 |
| Posted: Sat Mar 07, 2009 7:06 am Post subject: |
|
|
Poobah
Joined: 05 Jan 2008
Posts: 9471
Location: US: west coast, almost. Otherwise, enroute.
|
| Quote: |
| I donk know how to diferentiate "active" logs at host from inactive and/or archivable. |
Your z/OS WMQ support folks will need to print the BSDS log directory to determine which are active and which are inactive (archivable). There is a supplied utility to print the BSDS. Refer to the z/OS WMQ System Admin manual unit on managing the bsds. Use the print log map utility (CSQJU004) to print the contents of the BSDS.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
|
| Back to top |
|
|
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
|
|
