QUAT SATA-HAT writespeeds are awfull


I had a QUAT SATA-HAT (v1.2) with pi 4 and and i have a problem. I installed the HAT with 3 hdds and 1 ssd (2.5) and i can mount all the disks. 1 ssd and 1 hdd at “normal” disks and 2 hdds with software raid 1. but my write speeds are awfull. The command [XXX = sda]
sudo hdparam -tT /dev/XXX
had cached reads up to 740MB/s and without cache
sudo hdparam -tT --direct /dev/XXX
up to 270MB/s this is okay and enoght for me, but if copy datas the speeds are 20MB/s without raid and 50MB/s with raid.
messured with the command (in the mounted folder)
dd if=/dev/zero of=tempfile bs=1M count=1024 conv=fdatasync,notrunc.

so my questions.

  1. which sata ports are the best for my raid hdds ore it makes no difference
  2. had anybode a idea, why the speedtest okay and the write speeds of all the disks are so bad?.
  3. what is the maimum speeds of the SATA HAT?

With best regards


Is tempfile located at sd card?

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Hello, thanks for the answer

No, I am in the folder of the mounted disk. with Samba i hat create a nas and the folder size is the size of the disks, not the sd card, so I`m sure i copy the tempfile on the disks. If i copy datas with my network i have the same speed (20-30 MB/s).

I have same setup (3HHD, 1 SSD) and good speed:
Did you ensure to change your path to your SSD (mine: cd /mnt/video4) before start dd

dd if=/dev/zero of=tempfile bs=1M count=1024 status=progress
987758592 bytes (988 MB, 942 MiB) copied, 5 s, 197 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 5.54067 s, 194 MB/s


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I had 1 problem solved. I had used ntfs (not the best idea) at my ssd and with ext4 have a wirte speed about 200MB/s. Thats for the rates Michael.

Now I have nas speeds in my network about 80 MB/s HDD but my SSD hat speeds about 60 MB/s. I think it is a problem with samba, not with the SATA-HAT.

Thaks for your Help


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