| Is linear or circular logging more appropriate for the average MQ production system? |
| linear |
|
28% |
[ 6 ] |
| circular |
|
71% |
[ 15 ] |
|
| Total Votes : 21 |
|
| Author |
Message
|
| kolban |
 Posted: Thu Sep 05, 2002 11:57 am Post subject: A poll - linear logging or circular logging? |
 |
|
Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
|
Folks,
It seems that we have had a number of discussions on linear vs circular logging? I'd like to open a poll on this.
Is linear or circular logging more appropriate for the average MQ production system? |
|
| Back to top |
|
 |
| nimconsult |
| Posted: Thu Sep 05, 2002 9:40 pm Post subject: |
|
|
Master
Joined: 22 May 2002
Posts: 268
Location: NIMCONSULT - Belgium
|
I voted "circular" for the average production system.
Circular provides data and transactional recovery. You do not loose messages with circular logging!
I only recommend to use linear logging in two circumstances: ability to restore the queue manager configuration and data at a given point in time in the past (rcdmqimg), ability to perform log analysis (I have no relation with the company but have a look at an MQ log analyzis tool on www.cressida.info)
On zOS it is usual practice to define linear logging, because standard archiving procedures exist. On distributed systems I configure circular logging by default (but change -increase- the default values for the size).
_________________
Nicolas Maréchal
Senior Architect - Partner
NIMCONSULT Software Architecture Services (Belgium)
http://www.nimconsult.be |
|
| Back to top |
|
|
| jhalstead |
| Posted: Fri Sep 06, 2002 12:18 am Post subject: |
|
|
Master
Joined: 16 Aug 2001
Posts: 258
Location: London
|
I voted linear, but as per usual it really depends, however this type of thing always needsd to be driven by the business requirements:
1. Are there are regulatory issues to consider.
2. Can the business readily deal with having to reconcile interfaces.
3. Can the relevant systems re-despatch messages easily.
4. Are there impacts on business critical processes.
When a worst case scenrario occurs, (let say once in 5 years) where a core queue gets damaged when it has a few tens/hundreds of thousand messages on (let assume the application that was meant to be processing them was down for a period). I think it's a big ask to expect the business to perform a reconciliation and re-despatch any lost messages due to the fact that it's less effort to use circular logging. |
|
| Back to top |
|
|
| oz1ccg |
| Posted: Fri Sep 06, 2002 1:43 am Post subject: |
|
|
Yatiri
Joined: 10 Feb 2002
Posts: 628
Location: Denmark
|
I'm sorry but I can't wote, because it depends on the use of the queuemanager, is data staying there for some time. Let's say hours, and the amount of data might require liniar logging.
Or if the messages are just flowing thru in minutes/secs. this would give circular, so i needed the it depends choice.
Just my $0.02 
_________________
Regards, Jørgen
Home of BlockIP2, the last free MQ Security exit ver. 3.00
Cert. on WMQ, WBIMB, SWIFT. |
|
| Back to top |
|
|
| kolban |
| Posted: Fri Sep 06, 2002 5:37 am Post subject: |
|
|
Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
|
I voted for circular. I am balancing the administrative cost of archiving LOG files and ensuring those are safe and managed as compared to the cost involved in disk mirroring to prevent media corruption (through hardware failure).
If MQ media (the files holding the queues) can be corruptred by non-hardware issues then these same issues could just as easily corrupt linear logging data.
In my experience of MQ usage, I have yet to (personally) meet an MQ user who is using anything other than circular on distributed platforms. |
|
| Back to top |
|
|
| TonyD |
| Posted: Tue Sep 10, 2002 7:58 pm Post subject: |
|
|
Knight
Joined: 15 May 2001
Posts: 540
Location: New Zealand
|
| I have also moved from recommending linear logs to now preferring circular. I think most production systems these days would use some form of disk mirroring or replication so the chances of losing a queue due to media damage are pretty remote, you can run out of space in a linear log just as easily as a circular one, and the administration tasks are greater. However I would concede that there might be a situation (audit requirement for example) that would dictate using linear logging. |
|
| Back to top |
|
|
| jc_squire |
| Posted: Wed Sep 11, 2002 2:51 pm Post subject: |
|
|
Centurion
Joined: 14 Apr 2002
Posts: 105
Location: New Zealand
|
Circular !!!!!!!!
Yes, the business requirements will be the drive behind it so the average business requirement will determine what is the best solution for the average production system. So what is the average business requirement?
I have not come across an implementation requiring linear logging. Often customers need to regenerate messages as part of their day to day activities so the ability to regenerate data is included in the design of the system. MQ objects can be backed up when changes are made and restored if required. Hence, where is the need for linear logging?
Anyway, restoring data from linear logs is only as good as the latest log files you have available i.e. the log files you have are 1 hour old and do not contain the 10000 msgs sitting on the queue half an hour before the failure.
Regards
_________________
J C Squire
IBM Certified Specialist - MQSeries |
|
| Back to top |
|
|
| VivekMeshram |
| Posted: Wed Sep 11, 2002 8:58 pm Post subject: |
|
|
Voyager
Joined: 25 Mar 2002
Posts: 83
|
Most Clients Needed Linear Loging, if we explain them Linear/Circular logs in detailed, even we also says thats its depends on the requirements....but sincerely i would say Circular is the Best!!!
_________________
Thanks
Vivek S Meshram.
·IBM Certified Specialist – IBM WebSphere MQ v5.3 / v5.2 |
|
| Back to top |
|
|
| dgolding |
| Posted: Thu Sep 12, 2002 12:35 am Post subject: |
|
|
Yatiri
Joined: 16 May 2001
Posts: 668
Location: Switzerland
|
As the primary reason for using linear logging is to guard against disk failure, and as it is cheap and easy to mirror disks on almost all platforms, linear logging is a waste of time, IMHO.
The other reason is to guard against queue corruption when MQ craps out unexpectantly - far better to apply those CSDs instead!  |
|
| Back to top |
|
|
|
|
