[gpfsug-discuss] tuning parameters question

Aaron Knister aaron.s.knister at nasa.gov
Mon Sep 11 01:50:39 BST 2017


As an aside, my initial attempt was to use Ganesha via CES but the 
performance was significantly worse than CNFS for this workload. The 
docs seem to suggest that CNFS performs better for metadata intensive 
workloads which certainly seems to fit the bill here.

-Aaron

On 9/10/17 8:43 PM, Aaron Knister wrote:
> Hi All (but mostly Sven),
> 
> I stumbled across this great gem:
> 
> files.gpfsug.org/presentations/2014/UG10_GPFS_Performance_Session_v10.pdf
> 
> and I'm wondering which, if any, of those tuning parameters are still 
> relevant with the 4.2.3 code. Specifically for a CNFS cluster. I'm 
> exporting a gpfs fs as an NFS root to 1k nodes. The boot storm is 
> particularly ugly and the storage doesn't appear to be bottlenecked.
> 
> I see a lot of waiters like these:
> 
> Waiting 0.0009 sec since 20:41:31, monitored, thread 2881 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 26231 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 26146 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 18637 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 25013 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 27879 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 26553 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 25334 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> Waiting 0.0009 sec since 20:41:31, monitored, thread 25337 
> InodePrefetchWorkerThread: on ThCond 0x1800635A120 (LkObjCondvar), 
> reason 'waiting for LX lock'
> 
> and I'm wondering if there's anything immediate one would suggest to 
> help with that.
> 
> -Aaron
> 

-- 
Aaron Knister
NASA Center for Climate Simulation (Code 606.2)
Goddard Space Flight Center
(301) 286-2776



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