* Havasvölgyi Ottó:
> Even though the TPS in pgbench about 700 with 1 client.
> I have tried other sync methods (fdatasync, open_sync), but all are similar.
> Should I disable write cache on HDD to make it work?
Did you mount your ext4 file system with the nobarrier option?
By default, ext4 is supposed to cope properly with hard disk caches,
unless the drive is lying about completing writes (but in that case,
disabling write caching is probably not going to help much with
reliability, either).
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