Slow file copy I/O

Hi,

I have had a new issue arise in the past month or so that was not present when I initially installed CachyOS about 2 months ago. Just as background, I am a bit familiar with Arch as I have used in on and off for 15 years. I am able to navigate the system ok but I am definitely NOT an expert.

The issue: the write speed to all non-root drives has decreased to about 2 MB/s for all drives except the SATA SSD that CachyOS is installed on. The write speed for the root drive is normal (peaking at 500 MB/s and decreasing with sustained writes as would be expected.)

This is a newish motherboard, processor and fairly new drives, including 3 other SATA SSDs, and one fast NVME drive that is directly PCIE connected.

In addition to the fact that the write speeds to all of these mounted drives had been normal in CachyOS 2 months ago when I first installed it, running an Ubuntu Live USB today, all of the write speeds are normal. And when I boot into Windows10 (SATA SSD) all of the write speeds to all drives are normal

Thus, It does not appear to be a hardware problem.

However, in CachyOS, all other drives besides / (ZFS) are riduculously limited to 2 MB/sec (SATA, NVME, USB)

The same problem occurs whether the drives are mounted explicitly using /etc/fstab or with system-d mount.

I have tried looking at lsmod, lspci and hdparm variables, and can not find anything that seems funny – but again, I’m not an expert.

Hopefully, someone will be able to clue me in to which setting I jacked up inadvertently.

thank you

edit: I did notice that I had made one change to /etc/fstab: mounting so that users of the “otherdisks” group would have rw permissions on the mounted drives. Other than that, things look pretty default???

edit2: added $zfs list

[12beaae] (CachyOS log)

$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0   1.8T  0 disk 
├─sda1        8:1    0   100M  0 part 
├─sda2        8:2    0    16M  0 part 
├─sda3        8:3    0   1.8T  0 part /mnt/Windows10
└─sda4        8:4    0   522M  0 part 
sdb           8:16   0   3.6T  0 disk 
└─sdb1        8:17   0   3.6T  0 part /mnt/VideoDisk
sdc           8:32   0 894.3G  0 disk 
├─sdc1        8:33   0 894.2G  0 part 
└─sdc9        8:41   0     8M  0 part 
sdd           8:48   0   1.8T  0 disk 
├─sdd1        8:49   0     1G  0 part /boot
└─sdd2        8:50   0   1.8T  0 part 
zram0       254:0    0  61.9G  0 disk [SWAP]
nvme0n1     259:0    0   3.6T  0 disk 
└─nvme0n1p1 259:1    0   3.6T  0 part /mnt/CacheDisk
$ sudo zfs list
NAME                          USED  AVAIL  REFER  MOUNTPOINT
plexpool                      591G   270G    96K  none
plexpool/PLEX                 591G   270G   591G  /mnt/PLEX
zpcachyos                    1.51T   255G   192K  none
zpcachyos/ROOT               1.51T   255G   192K  none
zpcachyos/ROOT/cos           1.51T   255G   192K  none
zpcachyos/ROOT/cos/home      1.45T   255G  1.45T  /home
zpcachyos/ROOT/cos/root      29.3G   255G  29.3G  /
zpcachyos/ROOT/cos/varcache  26.1G   255G  26.1G  /var/cache
zpcachyos/ROOT/cos/varlog     836K   255G   836K  /var/log
$ cat /etc/fstab 
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a device; this may
# be used with UUID= as a more robust way to name devices that works even if
# disks are added and removed. See fstab(5).
#
# <file system>             <mount point>       <type>  <options>                                                             <dump>  <pass>
UUID=[XXXXX]             /boot               vfat    defaults                                                               0       2

UUID=[XXXXX]       /mnt/Windows10      ntfs3   defaults,uid=0,gid=1004,umask=0002                                     0       0

UUID=[XXXXX]       /mnt/VideoDisk      ntfs3   defaults,uid=0,gid=1004,umask=0002                                     0       0

UUID=[XXXXX]       /mnt/CacheDisk      ntfs3   defaults,uid=0,gid=1004,umask=0002                                     0       0

UUID=[XXXXX]              /mnt/android        exfat   defaults,nofail,x-systemd.device-timeout=1s,uid=0,gid=1004,umask=0002  0       0
$ inxi -b
System:
  Host: pfunk Kernel: 6.12.1-2-cachyos arch: x86_64 bits: 64
  Desktop: GNOME v: 47.2 Distro: CachyOS
Machine:
  Type: Desktop System: ASUS product: N/A v: N/A serial: <superuser required>
  Mobo: ASUSTeK model: ProArt X670E-CREATOR WIFI v: Rev 1.xx
    serial: <superuser required> UEFI: American Megatrends v: 2204
    date: 08/02/2024
CPU:
  Info: 16-core AMD Ryzen 9 7950X [MT MCP] speed (MHz): avg: 3010
    min/max: 545/5881
Graphics:
  Device-1: NVIDIA AD102 [GeForce RTX 4090] driver: nvidia v: 565.57.01
  Device-2: Blackmagic Design DeckLink Mini Monitor 4K driver: blackmagic-io
    v: 14.3a5
  Device-3: Advanced Micro Devices [AMD/ATI] Raphael driver: amdgpu
    v: kernel
  Display: wayland server: X.Org v: 24.1.4 with: Xwayland v: 24.1.4
    compositor: gnome-shell driver: gpu: nvidia,nvidia-nvswitch
    resolution: 3840x2160~60Hz
  API: OpenGL v: 4.6.0 compat-v: 4.6 vendor: nvidia mesa v: 565.57.01
    renderer: NVIDIA GeForce RTX 4090/PCIe/SSE2
Network:
  Device-1: MEDIATEK MT7922 802.11ax PCI Express Wireless Network Adapter
    driver: mt7921e
  Device-2: Intel Ethernet I225-V driver: igc
  Device-3: Aquantia AQtion AQC113CS NBase-T/IEEE 802.3an Ethernet [Antigua
    10G] driver: atlantic
Drives:
  Local Storage: total: 11.79 TiB used: 9.56 TiB (81.0%)
Info:
  Memory: total: 64 GiB available: 61.93 GiB used: 8.68 GiB (14.0%)
  Processes: 841 Uptime: 3h 27m Shell: fish inxi: 3.3.36

Update: No idea what the problem was. I reinstalled CachyOS from scratch from the latest Installer USB. Now working normally.

???