Which process is doing all the writing

idwalton72 · #1 (**permalink**) 09-01-2009

Hi

We are running an IBM P570 with AIX and Unidata.

The disk monitor in nmon is showing that one of our logical volumes is hitting 100% most of the time, and that 98% of it is write.

I am trying to identify the top processes in terms of disk IO, obviously particularly write so that we can get the developers to look at the code.

Can anybody help me?

Thanks

vbe · #2 (**permalink**) 09-01-2009

Could be swap space...
To check:

Code:

lsps -a

idwalton72 · #3 (**permalink**) 09-01-2009

Quote:

Originally Posted by vbe

Could be swap space...
To check:

Code:

lsps -a

What is on that lvol?
to see who is using (open files...) the filesystem use the fuser command

Thanks - Done this and the swap space in hdisk0...

The hdisk2 volume contains our unidata database files.

vbe · #4 (**permalink**) 09-01-2009

The hdisk2 is not a logical volume but a physical volume (LUN probably...)
to see what it holds (in term of logical volume / filesystem ): e.g.

Code:

on4:/home/vbe $ lspv hdisk2
PHYSICAL VOLUME:    hdisk2                   VOLUME GROUP:     vg01
PV IDENTIFIER:      00cb574e8531bb48 VG IDENTIFIER     00cb574e00004c000000011589f89af3
PV STATE:           active                                     
STALE PARTITIONS:   0                        ALLOCATABLE:      yes
PP SIZE:            64 megabyte(s)           LOGICAL VOLUMES:  7
TOTAL PPs:          945 (60480 megabytes)    VG DESCRIPTORS:   1
FREE PPs:           0 (0 megabytes)          HOT SPARE:        no
USED PPs:           945 (60480 megabytes)    MAX REQUEST:      256 kilobytes
FREE DISTRIBUTION:  00..00..00..00..00                         
USED DISTRIBUTION:  189..189..189..189..189                    
on4:/home/vbe $ lspv -l hdisk2
hdisk2:
LV NAME               LPs   PPs   DISTRIBUTION          MOUNT POINT
lv106                 8     8     00..00..00..00..08    /data/systeme
lv105                 2     2     00..00..00..00..02    /var/opt/ofa/pof1
lv102                 2     2     00..00..00..00..02    /data/ofa/pof1/cm/admin/pof1/int-pbdg
lv101                 2     2     00..00..00..00..02    /data/ofa/pof1/cm/admin/pof1/out
lv104                 11    11    00..00..00..00..11    /opt/ofa
lv103                 10    10    00..00..00..00..10    /data/ofa/export
lv100                 910   910   189..189..189..189..154 /data/ofa/pof1

zxmaus · #5 (**permalink**) 09-02-2009

I assume that is where journaling is done - I don't know much about unidata but as far as I understand this is a bit like the redo-logs. If you have a bad distribution of your filesystems, this can easily produce a hot disk.

filemon and fileplace commands could give you more information about what is on the disk - and if you have nmon on your box, you can sort by IO or you can use

Code:

ps vx | head -1; ps vx | grep -v PID | sort -rn +4 | head -10

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