RE: wrkdsksts question

["Andy Nolen-Parkhouse" <aparkhouse@xxxxxxxxxxx>]

Oliver,

The display below will record physical activity on your drives, not I/O
requests from your programs.  When your programs issue a read request the
system will grab a large chunk of the file and load it into main storage.
Subsequent read requests may be satisfied from main storage without the need
to go back to the disk.  The default behavior is that your writes will go
directly to disk (or the disk controller buffer) on every occasion.  So
unless your system is overstressed in some way, it makes sense to have fewer
physical reads than writes.

Regards,
Andy Nolen-Parkhouse

> Hi,
> 
> when I look at the wrkdsksts display, I'm coming up with a question:
> 
> why are the write requests constantly much higher than the reads? I would
> have expected the opposite.
> These are 4326 units with 35GB each on an 810 at about 50%.
> 
> 
>   I/O   Request   Read  Write   Read  Write    %
>   Rqs  Size (K)    Rqs   Rqs     (K)   (K)   Busy
>   7,6      5,0     3,2    4,3    4,0    5,7     9
>  20,2      4,7    16,9    3,2    4,4    6,3     5
> 195,6      4,3     1,9  193,7    7,2    4,2    10
> 214,5      4,3    21,0  193,4    4,8    4,2     4
> 195,5      4,4     1,6  193,9    5,1    4,4     0
> 214,7      4,5    20,9  193,7    4,7    4,4     9
> 214,3      4,3     1,0  213,2    5,4    4,3     0
> 234,4      4,3    21,3  213,1    4,7    4,3     4
> 209,0      4,2     1,3  207,6    5,1    4,2     0
> 232,4      4,2    24,8  207,5    4,6    4,2     9
> 198,4      4,3     1,5  196,8    7,7    4,2     4
> 218,5      4,3    21,6  196,8    4,8    4,2     9
> 202,6      4,3     2,1  200,4   14,4    4,2     9
>                                               More..