[Sblim-devel] Re: [Ibmcimom-devel] discussion point : How to handle mass operations ?!?

[Viktor M. <mih...@de...>]

Hi,

something that comes to my mind would be a slight(?) modification of the
schema. How about modelling extents as groups and not as single
entities. I would expect that extents are usually handled in a way that
<n> consecutive extents are assigned to a logical volume at once instead
of one at a time. Of course one could still assign single extents, in
which case we would end up with single-extent groups (being the just
penalty for this kind of folly:-).
Any thoughts or comments on that?

> 
> "Heidi Neumann" <HEI...@de...> on 18/07/2001 16:08:06
> 
> Please respond to "Heidi Neumann" <HEI...@de...>
> 
> To:   sbl...@dw..., ibm...@op...
> cc:
> 
> Subject:  [Ibmcimom-devel] discussion point :  How to handle mass
>       operations ?!?
> 
> Hi ,
> 
> the goal of this mail is to start a discussion about how
> to handle mass operations . It is not always the best
> solution to avoid them .
> 
> At the moment I'm running in such a mass problem with
> the instrumentation of "Filesystems & Volume Management"
> and I'm not sure how to solve the forced crashes .
> 
> PROBLEM DESCRIPTION
> 
> - affected module  :   sblim-fsvol-0.6.1   ( tar.gz  )
>                        FSVOL_0_6_1         ( CVS tag )
> - affected part    :   the instrumentation of the Logical
>                        Volume Manager for Linux (LVM)
> 
> - affected class   :   LVM_PVExtent
> Each instance of the class LVM_PVExtent represents one
> physical extent in the Linux Logical Volume Manager (LVM) .
> 
> - provider code    :
> 
>    * com/ibm/wbem/linux/device/LVM_PVExtent.java :
>      calling the NPI - uninteresting in the problem
>      environment
> 
>    * LVM_PVExtent.c :
> 
>      1 step : enumeration of all physical volumes
>               -> 6 physical volumes
> 
>      2 step : for each instance of the physical volume
>               all physical extents are collected in a list
>               -> ~ 4000 = sum of all physical extents
>               ! this happens in functions of the tool
>                 library CimFsVMgmt.c whithout any problems !
> 
>      3 step : for each entry in the list of physical
>               extents one instance of LVM_PVExtent is
>               created ... no - should be created
> 
> This enumeration of all instances of the class LVM_PVExtent
> brings on the problem how to handle this mass operation
> and avoid crashes .
> 
> Now one discussion point can be why it seems to be
> necessary to do such a "maybe useless" operation . It is,
> from a systems management application view, really necessary
> to get all the physical extents of one system to have a look
> in the way they are connected to their corresponding logical
> extents and the logical volume ? What might be a case where
> this granularity becomes important ( Standard value fo a
> physical extent is 4096 kB !!! ) .
> Or shall there be other ways to offer detailed informations .
> 
> An other discussion point can be, how to solve such problems
> whithout avoiding enumerations with a mass result . I' sure
> that there are other environments where it is not possible
> to strike out operations that have a mass result .
> 
> Now follow some possible solutions as discussion basics .
> 
> POSSIBLE SOLUTIONS
> 
> * increase the memory allocation size for the Java Virtual
> Machine ???
> 
> * take this granularity out of the schema
> ( delete LVM_PVExtent ) ???
> 
> * more suggestions ???
> 
> Thanks for your attention ... Heidi
> 
> Mfg / Regards
> 
> Heidi Neumann
> 
> IBM Laboratory Boeblingen - Germany - Dept. 3243
> LTC  - -  Linux Technology Center -- 7UFA
>                   Systems Management
> 
> Phone : ++49 (0) 7031 / 16 - 3193
> Schönaicher Str. 220, 71032 Böblingen
> 
>         hei...@de...
> --- try sametime to contact me ---
> 
> http://w3.opensource.ibm.com/projects/ibmcimom/
> http://oss.software.ibm.com/developerworks/projects/sblim/
> 
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-- 
Kind Regards / Mit freundlichen Grüßen
  Viktor Mihajlovski
  
  Linux Technology Center

  IBM Laboratory Böblingen, Germany
  Phone +49-7031-16-2560
  Email mih...@de...