Disk top usage PIDs
dudu.meyer at gmail.com
Tue Nov 4 07:02:10 PST 2008
On Tue, Nov 4, 2008 at 12:55 PM, Bill Moran <wmoran at potentialtech.com> wrote:
> In response to "Eduardo Meyer" <dudu.meyer at gmail.com>:
>> On Tue, Nov 4, 2008 at 12:27 PM, Eduardo Meyer <dudu.meyer at gmail.com> wrote:
>> > On Tue, Nov 4, 2008 at 12:18 PM, Bill Moran <wmoran at potentialtech.com> wrote:
>> >> In response to "Eduardo Meyer" <dudu.meyer at gmail.com>:
>> >>> I have some serious issue. Sometimes something happens and my disk
>> >>> usage performance find its limit quickly. I follow with gstat and
>> >>> iostat -xw1, and everything usually happens just fine, with %b around
>> >>> 20 and 0 to 1 pending i/o request. Suddely I get 30, 40 pending
>> >>> requests and %b is always on 100% (or more than this).
>> >>> fstat and lsof gives me no hint, because the type of programs as well
>> >>> as the amount of 'em is just the same.
>> >>> How can I find the PID which is hammering my disk? Is there an "iotop"
>> >>> or "disktop" tool or something alike?
>> >> top -m io -o total
>> > Great, thats exactly what I was looking for, thank you a lot Mr Moran.
>> I see syncer (40%) and bufaemon (10%) and after that, imapd. The first
>> ones are kernel PIDs (36 and 37).
>> PID USERNAME VCSW IVCSW READ WRITE FAULT TOTAL PERCENT COMMAND
>> 36 root 2 2 0 31 0 31 40.79% bufdaemon
>> 37 root 2 2 0 16 0 16 21.05% syncer
>> 71501 vmail 4 0 0 0 0 0 12.00% imapd
>> I guess it a symptom of some hardware problems, kernel itself is not
>> supposed to do this many I/O, right?
>> Sometimes PID 39, softdepflush, is always on top 3.
> Off the top of my head, it looks like you're exceeding what the hardware
> can do. What kind of disks do you have in that system? It may be time
> to get faster disks or expand to a high-performance RAID setup.
Master: ad4 <Hitachi HDP725050GLA360/GM4OA52A> Serial ATA II
I still think its a hw (disk or controller) problem.
I have raised the following:
Now, my disk usage is back to 30%
> Bill Moran
pessoal: dudu.meyer at gmail.com
profissional: ddm.farmaciap at saude.gov.br
More information about the freebsd-questions