Very High Disk Utilisation

[marvik]

Hi friends,
One of our servers is going 100% Disk utilisation.Glance output is below.This disk is not part of any VG but still high Physical Reads.How can i find which process is reading them.Also there are many defunct processes in the box.Pls advice and incase any further info is needed

Disk Detail for: 0/2/1/0.1.50.0.0.0.5 Bus Type: scsi
Controller: na Product ID: CX500WDR5 Vendor: DGC
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Log Reads : 0.0 Phy Reads : 567.1 Util (%): 100 q=0 (%): 100
Writes : 0.0 Writes : 4.2 Q Len : 0.0 0 Rd Bytes: 0.0 Rd Bytes: 4765.7 2 Wt Bytes: 0.0 Wt Bytes: 34.2 4--------------------------------------------------------------------------------
Mapping Information
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Partition :/dev/dsk/c26t0d5
Partition :/dev/rdsk/c26t0d5

[Rasheed Tamton]

Hi Marvik,

pvdisplay -v /dev/dsk/c26t0d5
will show you which VG the disk belongs to and the LVs associated with it - if any.

strings /etc/lvmtab|grep "/dev/dsk/c26t0d5"
will also show you the VG.

lsof will show you the open processes

fuser also will show you the open processes

You said disk is not part of a VG!!

Please check it with pvdisplay

Also use iostat to see the disk i/o.

rgds,

[Steven E. Protter · Accepted solution]

Shalom,

The defunct processes could be doing needless i/o and should be killed. If they won't die, reboot the system.

defunct processes are usually created by bad application code and that issue needs to be investigated to prevent a recurrance.

http://www.hpux.ws/system.perf.sh

My set of performance measurement tools based on a set HP gave me a few years back.

SEP

[Jollyjet]

The disk will be defnitely part of vg you can run vgdisplay or strings /etc/lvmtab

and find which lvol is there in the particular disk and check the space of the lvol if it's possible send the output of strings /etc/lvmtab and bdf and vgdisplay output.

[marvik]

Thanks SEP and Evrybody,

Actually that link is a alternate link.the Primary link to that is a par of a VG and powerpath is running on this box.IO is happening on the alternate path(c26t0d5) and not the primary path(c25t0d5).We have asked to business to reboot the box to get rid of the defunct processes.Let's see after that

Cheers!
Marvik

[marvik]

Thanks!