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rsync reports a transfer speed of 35-45 MB/s when transfering large video files from one drive to another. Is this what I should expect?
I see roughly the same rate whether I'm transfering from one internal drive to another, or from an internal drive to a similar drive mounted in a USB enclosure.
PC = Dell 5820 Tower [2017]
CPU = Xeon W-2135
Internal SATA ports
External USB-3.1 Gen 1 ports (same as USB 3.0 ???)
Filesystem = btrfs
Encryption = whole disk, luks
Drive = Crucial 4TB MX500 SATA SSD, 6 Gb/s
Enclosure = Sabrent 2.5" SATA to USB 3.0 External Hard Drive Enclosure
Alt Drive = Samsung 2TB 970 EVO Plus NVMe M.2 Internal SSD
Enclosure = Sabrent NVMe PCIe M.2 to USB 3.1 Gen 2 USB Type-C SSD Enclosure
1. Should I ignore the rate indicated by rsync and use other metrics instead?
2. The drives are encrypted. But once the drives are unlocked and mounted, should I expect the same transfer speed as to an unencrypted drive?
3. I would expect the Samsung to be limited by the 3.1 Gen 1 port... around 5 Gbps ==> 625 MB/s (minus overhead)
4. I would expect the Crucial to be limited by the 3.0 enclosure... which is actually the same thing as 3.1 Gen 1 ??? (so, same speed)
5. I could see where transfering from one USB port to another might reduce the throughput (the bandwidth is for the bus, not the port, right?), but that shouldn't affect a SATA to USB transfer.
Either way, I'm getting maybe 5-15 % of the throughput I expect.
To test throughput:
head -c 1GB /dev/urandom > /tmp/testfile
time bash -c 'cd /mnt/usb && mv /tmp/testfile . && sync -f testfile'The first time I run this test, I get around 11 sec ==> 85-90 MB/s.
Subsequent tests are around 2-3 sec, but this must be due to some sort of caching, right?
So, let's say 85-90 MB/s is correct. Is that what I should expect?
Cheers,
Last edited by dakota (2024-07-31 09:43:48)
"Before Enlightenment chop wood, carry water. After Enlightenment chop wood, carry water." -- Zen proverb
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