[gpfsug-discuss] gpfs waiters debugging

Stijn De Weirdt stijn.deweirdt at ugent.be
Tue Jun 6 14:06:57 BST 2017


oh sure, i meant waiters that last > 300 seconds or so (something that
could trigger deadlock). obviously we're not interested in debugging the
short ones, it's not that gpfs doesn't work or anything ;)

stijn

On 06/06/2017 02:57 PM, Frederick Stock wrote:
> Realize that generally any waiter under 1 second should be ignored.  In an 
> active GPFS system there are always waiters and the greater the use of the 
> system likely the more waiters you will see.  The point is waiters 
> themselves are not an indication your system is having problems.
> 
> As for creating them any steady level of activity against the file system 
> should cause waiters to appear, though most should be of a short duration.
> 
> 
> Fred
> __________________________________________________
> Fred Stock | IBM Pittsburgh Lab | 720-430-8821
> stockf at us.ibm.com
> 
> 
> 
> From:   Stijn De Weirdt <stijn.deweirdt at ugent.be>
> To:     gpfsug-discuss at spectrumscale.org
> Date:   06/06/2017 08:31 AM
> Subject:        Re: [gpfsug-discuss] gpfs waiters debugging
> Sent by:        gpfsug-discuss-bounces at spectrumscale.org
> 
> 
> 
> hi bob,
> 
> waiters from RPC replies and/or threads waiting on mutex are most 
> "popular".
> 
> but my question is not how to resolve them, the question is how to
> create such a waiter so we can train ourself in grep and mmfsadm etc etc
> 
> we want to recreate the waiters a few times, try out some things and
> either script or at least put instructions on our internal wiki what to 
> do.
> 
> the instructions in the slides are clear enough, but there are a lot of
> slides, and typically when this occurs offshift, you don't want to start
> with rereading the slides and wondering what to do next; let alone debug
> scripts ;)
> 
> thanks,
> 
> stijn
> 
> On 06/06/2017 01:44 PM, Oesterlin, Robert wrote:
>> Hi Stijn
>>
>> You need to provide some more details on the type and duration of the 
> waiters before the group can offer some advice.
>>
>> Bob Oesterlin
>> Sr Principal Storage Engineer, Nuance
>>
>>
>>
>> On 6/6/17, 2:05 AM, "gpfsug-discuss-bounces at spectrumscale.org on behalf 
> of Stijn De Weirdt" <gpfsug-discuss-bounces at spectrumscale.org on behalf of 
> stijn.deweirdt at ugent.be> wrote:
>>
>>
>>     but we are wondering if and how we can cause those waiters ourself, 
> so
>>     we can train ourself in debugging and resolving them (either on test
>>     system or in controlled environment on the production clusters).
>>
>>     all hints welcome.
>>
>>     stijn
>>     _______________________________________________
>>
>>
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