[hobbit] performance issue with multiple pagesets

[Henrik Stoerner]

On Wed, Jul 20, 2005 at 06:14:04PM +0200, Olivier Beau wrote:
> 
> i've disabled [rrdstatus] and [rrddata].
> i still have lots of I/O, practicaly no change.

OK, so you just have a lot of disk I/O for those pages.

> i'm moved my www directory on another disk, and now most of the iowait is on the
> other disk.  i then moved www in ramdisk, and all the iowait disapeared !

Just checking - the [bbstatus] module in hobbitlaunch.cfg is disabled ?
It should be, or you *will* have lots of disk I/O.

> here is a paste of bbgen report, and then a paste of the unix bbgen report
> (witch are similar whether www is on disk or ram):

>  Hosts               :  1617
>  Status messages     :  8359
>  Pages               :   390

OK, so your main view if split on quite a few pages...

> Hobbit pagegen done                      1121874344.373265          2.830655 
> TIME TOTAL                                                          3.378925 

and it takes 3.4 seconds to generate the main view with those 390 pages.
Not a lot. The other pageset takes even less:

> Hobbit pagegen done                      1121874421.586783          0.087858 
> BB2 generation done                      1121874421.606831          0.020048 
> BBNK generation done                     1121874421.607756          0.000925 
> TIME TOTAL                                                          0.516614 

0.5 secs total, and about 0.1 seconds to generate that page.

So building all of your pagesets should not take more than 5-10 seconds
max. Your system should be idle at least 80% of the time.

Your system is probably doing a great job of buffering the disk writes,
but I really can't see what the big problem is.

What OS are you running ?


Regards,
Henrik