[gpfsug-discuss] Slow performance on writes when using direct io

[Peter Hruška]

Hello,

We encountered a problem with performance of writes on GPFS when the application uses direct io access. To simulate the issue it is enough to run fio with option direct=1. The performance drop is quite dramatic - 250 MiB/s vs. 2955 MiB/s. We've tried to instruct GPFS to ignore direct IO by using "disableDIO=yes". The directive didn't have any effect. Is there any possibility how to achieve that GPFS would ignore direct IO requests and use caching for everything?


--

S přáním pěkného dne / Best regards

Mgr. Peter Hruška
IT specialista

M Computers s.r.o.
Úlehlova 3100/10, 628 00 Brno-Líšeň (mapa<https://mapy.cz/s/gafufehufe>)
T:+420 515 538 136
E: peter.hruska at mcomputers.cz<mailto:peter.hruska at mcomputers.cz>

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