RE: Very slow scp performance comparing to Linux

> The throughput on FreeBSD went up significantly from 50 MB/s to 630 MB/s with
> NIC interface. Linux went up modestly form 550 MB/s to 660 MB/s.
>
> So, looks in the non-tmpfs case, the Linux ext4 filesystem does cache large amounts
> of data in memory, much larger than FreeBSD ufs.
>
linux filesystem caching is just stupid, optimized to show up good in 
benchmarks.

It just accepts writes as long as there is available memory, without 
writing anything to disk, then if it cannot do it anymore or some time 
passed, schedules huge amount of writes, often stalling whole system.

This is how it was almost 20 years ago when i was still using linux, seems 
like didn't change much.

Just think how much data loss and inconsistency would occur if there will 
be crash or power loss after "writing" 100000 files of 10GB which can 
easily be done in short time as linux just doesn't block writing process 
at all and fill memory.

Since i started using FreeBSD UFS, many machines, lighter of heavier 
workload, always mixed workload, i never ever have more that a few files 
loss on power outage.