Write speeds JMS561

#1

I was wondering what speeds people are seeing when writing to discs over the JMS561? The spec says they can do 400 Mbytes/s however I am seeing significantly less.

My setup:
Macbook wired to Pi over gigabit switch - 940 Mbit/s with iperf (~117 MByte/s)
4TB WD Red NAS HDD - Max 150 Mbyte/s
JMS561 SATA Hat on Pi - 400 Mbyte/s spec
Samba share from Pi to Macbook

Taking overhead into account I would expect something around 100 MByte/s when writing over the network, however I am only seeing between 25-30 Mbyte/s right now… My feeling is that Samba is to blame, I am going to give NFS a try and see if that helps.

What is everyone else seeing on their setups?

Raid 5 40MB Write Speed
Issues with data transfer speed and disk temperature
#2

Use dd or iperf directly on Raspberry Pi to get more accurate data.

#3

@quadnas

I’ve had ~11500 kB/s (11.5 MB/s) write speed on Rock Pi via samba when my home Ethernet was 100 Mb/s.

Later and for now I have ~115000 kB/s (115 MB/s) write speed in the same situation but I’ve changed Ethernet to 1 Gbps.

On stand-alone Rock Pi and SSD drive connected via USB 3.0, when I test the write speed I’ve got 240 MB/s writing simple file of NULs. In the same situation when I write to eMMC, I have 134 MB/s.

#4

I used iperf to test the connection speed, I get 940 Mbit/s

I used dd to test the write speed to the HDD, I got ~150 Mbyte/s with multiple block sizes

So I am pretty confused why I am getting max 30 Mbyte/s over the network…

I ran an additional dd test writing to the SD card in the Pi instead of the Sata HDD, and this test got 30 Mbyte/s, which is about the same speed I get over the network…this leads me to believe the data is somehow first being written to the SD and then copied to the HDD, but this seems strange.

Any ideas?

#5

Run iotop command when copying from samba, check which speed exactly it is.

#6

I ran iotop and got between 24-31 MB/s for the Total disk write. The Current disk write jumped all over the place so I am not sure how to interpret that.

root 0.00 B/s 24.05 M/s 0.00 % 0.00 % mount.ntfs-3g /dev/sdb /media/share -o rw,nosuid,noexec

I have tried Samba and NFS, both gave same results. I also tested a linux, windows and osx client, all gave the same result. I am running out of ideas, the only idea I have is to try out some other versions of the firmware, I am currently on the latest version.

#7

Aha! The culprit is ntfs.

Try to use ext4 or another Linux filesystem.

1 Like
#8

@setq Yes, NTFS is treated differently. I’ve already posted in other thread, that speeds on NTFS are amazingly low. And I also got max 30 MB/s.

#9

Wow, thank you! I would not have thought of that.

I just plugged in an ext4 drive I have, huge difference.

Copying directly via the finder to samba connected share, I see ~100 MB/s on iotop.
CPU usage reaches 90% on 1 of the cores.

Using rsync over ssh I am maxing out around 60 MB/s.
CPU usage reaches 100% on 1 of the cores, so I think this may be CPU limited by the Pi.

#10

FYI I reformated both my drives to ext4 and I now see ~110 MB/s over my network, very pleased! :slight_smile: