Hello Pancho!

Tuesday December 01 2020 19:45, you wrote to druck:

 >> It will still be quicker than the old PATA drives on a old 386
 >> system.
 >>
 >> My Pi4 which I use as an NFS file server with a USB attached 2.5"
 >> hard drive and it does about 100MB/s locally and 50MB/s over the
 >> network.
 >>

 > Mi rPi4 Samba file server using two USB attached drives gives:

 > SSD I get 345 MB/s local read, 110MB/s over the network read&write.

 > I get slightly slower than you for a very old laptop 2.5" HDD. 90 MB/s
 > local, 45MB/s network.

 > Local was measured using hdparm.

 > I'm curious as to why the 2.5 HDD is only half speed over the network?


This is not so difficult to work out starting with the results you got so:

345 MB/s  = 3450 Mb/s  b = bits.
110 Mb/s  = 1100 Mb/s.

What is the speeds of a USB  port ?

USB 3 same as 3.1 (gen 1) defaults to 480 Mb/s but can go to 5 Gb
USB 3.1 gen 2 is speeds up to 10Gb.

USB 3.2 has :

Gen 1x1 (previously known as USB 3.1 and USB 3.0) = 5Gb

Gen 1x2  = 10Gb

Gen 2x1  (previously known as 3.1 gen 2) = 10Gb

Gen 2x2  20Gb.

These speeds are the USB standard and does not mean that the mobo manu fully
supports these speeds not that the specific hardware that is linked to them
does the same as other I/O gets in the way.

Read speeds are always better than twice as fast as Write speeds as more work
is needed at least for SSD units as it has to find a clean sector.

Hence another reason foir using fstrim nightly.  fstrim is part of 
linux-utils.

It should be installed as standard if the install system sees's one but that
does depend on the distro authors.

Note that the Pi4B spec shows that 2 USB 3.0 and 2 USB 2.0 ports are fitted so
not that fastest available but for the brand nothing new as they are hardly
working any where near the edge of technology other than having a Gigabit
Ethernet port which could be used say with a fast NAS.


Vincent

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