[gpfsug-discuss] Long I/O's on client but not on NSD server(s)

[J Martin Rushton]

I saw something similar a good few years ago (ie on an older version of
GPFS).  IIRC the issue was one of contention: one or two served nodes
were streaming IOs to/from the NSD servers and as a result other nodes
were exhibiting insane IO times.  Can't be more helpful though, I no
longer have access to the system.

Regards,

J Martin Rushton MBCS


On 04/10/18 20:54, Buterbaugh, Kevin L wrote:
> Hi All,
>
> What does it mean if I have a few dozen very long I/O’s (50 - 75
> seconds) on a gateway as reported by “mmdiag —iohist” and they all
> reference two of my eight NSD servers…
>
> … but then I go to those 2 NSD servers and I don’t see any long I/O’s
> at all?
>
> In other words, if the problem (this time) were the backend storage, I
> should see long I/O’s on the NSD servers, right?
>
> I’m thinking this indicates that there is some sort of problem with
> either the client gateway itself or the network in between the gateway
> and the NSD server(s) … thoughts???
>
> Thanks in advance…
>
> —
> Kevin Buterbaugh - Senior System Administrator
> Vanderbilt University - Advanced Computing Center for Research and
> Education
> Kevin.Buterbaugh at vanderbilt.edu
> <mailto:Kevin.Buterbaugh at vanderbilt.edu> - (615)875-9633
>
>
>
>
>
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