[gpfsug-discuss] mmcrfs issue

[valdis.kletnieks at vt.edu]

On Mon, 13 Mar 2017 20:06:29 -0400, Aaron Knister said:
> After setting the sync=always parameter to not lose data in the event of 
> a crash or power outage the write performance became unbearably slow 
> (under 100MB/s of writes for an 8+2 RAIDZ2 if I recall correctly). I 

Not at all surprising. Forcing a 'sync every write' has been painful for pretty
much everything - first time I saw it was on a SunOS 3.2 box doing NFS over 3
decades ago.

> I've got an RFE open with IBM 
> (https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=84994)
> to see if the behavior of GPFS could be changed such that it would issue 
> explicit cache flushes that would allow it to work with ZFS (it might 
> even be beneficial in FPO environments too).

Do you have a suggestion for how to do this without it turning into 'sync=always'
just done at a different layer in the stack?
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