Re: Journal performance problems

[Alexei Pytel <pytel@xxxxxxxxxx>]

> The journals are located in ASP2, which has 1 (mirrored) disk drive with 

> about 17.5GB capacity (type 6718).

You've said "journals" - more than one...
If more than one journal receiver is on the same arm, you are in trouble 
(because disk arm has to move around a lot, as jobs write entries into 
different receivers).
The performance recommendation always was to isolate a *single* journal 
receiver in its own ASP.
If you have more than one receiver in a separate ASP with small number of 
arms, let alone in a single arm ASP - this is the worst performing 
configuration.
You will be much better off moving all journal receivers to system ASP.
Another posibility is to journal everything to a single journal (therefore 
single journal receiver) and has it in a separate ASP.


    Alexei Pytel
always speaking for myself





oliver.wenzel@xxxxxxxxxxxxxxxxxxxxxxx
Sent by: midrange-l-bounces@xxxxxxxxxxxx
05/01/2003 04:32 AM
Please respond to Midrange Systems Technical Discussion

 
        To:     midrange-l@xxxxxxxxxxxx
        cc: 
        Subject:        Journal performance problems



Hello,

well, we are currently setting up our HA solution (DataMirror). 
Therefore, we had to start journalling on all production files.

The journals are located in ASP2, which has 1 (mirrored) disk drive with 
about 17.5GB capacity (type 6718).

We now find we have severe performance problems some times. There's an 
invoicing job that normally runs about 1:30 hours and now takes 2:30 w/o 
much change in database activity. The only other active batch job at that 
time is also database intensive and runs longer than normally.

My guess is these jobs are waiting for journal entries to be written. The 
ASP2 disk drive is very busy at that time.

Any ideas on how to confirm this?

Also, we could add a disk drive to ASP2, which should help some. Or might 
it be better to cancel ASP2 and add the disks to ASP1? 

I've started Management Central performance monitoring to get a better 
look at system activity.

Any suggestions?

Regards,

Oliver