Ubuntu

14.04 File Transfers Send Slowly, but Receive Full Speed

Asked by Rob

My 14.04 Server LTS install has speed issues sending files (typically multi-GB ones) over the LAN. I can send to the server at essentially full gigabit speeds (~100 MB/s), but downloading from the server occurs at a fraction of that. Best case it hits full speed briefly and then slows to 30 MB/s or less.

On a previous 12.04 install (this new one is not an upgrade, but a fresh install), I could get full gigabit speeds both directions.

Some facts:
iperf reports full gigabit speed, even with longer transfer durations.
Memory usage appears low during transfers (landscape-sysinfo reports it in the sub 10% range), as does CPU load.
Disk speed seems to be more than adequate to saturate gigabit ethernet. The main storage I'm transferring to/from is a Linux software RAID5 array.
This happens over AFP (netatalk), SMB and SFTP.
Directly connecting over ethernet didn't appear to make any difference.
I got similar results with an install of 15.04 Server.
The NIC is an Intel 82574L using the e1000e driver, integrated on a Supermicro X9SCL-F motherboard. It reports being connected at 1000Mb/s Full-duplex (and iperf confirms this).

Given that my drives and network interface seem to be operating at full speed, and the problem occurs over multiple file transfer protocols, I'm not sure where to start troubleshooting. Any suggestions would be greatly appreciated!

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Rob
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actionparsnip (andrew-woodhead666) said : 		#1

What protocol are you using to send the data?

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actionparsnip (andrew-woodhead666) said : 		#2

What is the output of:

sudo lshw -C network

Thanks

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Rob (grmm) said : 		#3

As mentioned, I've tried AFP (using netatalk), SMB and SFTP.

sudo lshw -C network returns:
  *-network
       description: Ethernet interface
       product: 82574L Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: p4p1
       version: 00
       serial: 00:25:90:a8:f5:86
       size: 1Gbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k duplex=full firmware=2.1-2 ip=192.168.1.10 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
       resources: irq:16 memory:dfa00000-dfa1ffff ioport:e000(size=32) memory:dfa20000-dfa23fff
  *-network DISABLED
       description: Ethernet interface
       product: 82574L Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: p6p1
       version: 00
       serial: 00:25:90:a8:f5:87
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k firmware=2.1-2 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:18 memory:df900000-df91ffff ioport:d000(size=32) memory:df920000-df923fff

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Rob (grmm) said : 		#4

So after banging my head against a wall for a while, and trying other OSes, it turns out the issue was actually on the receiving end.

I hadn't thought to consider disk problems with my desktop, as it has a fairly recent SSD. However with lots of writes and deletes recently and being close to full at times, combined with a lack of TRIM, write speeds had gone way down.Enabling TRIM and doing some disk maintenance got speeds back up and allowed me to verify that it wasn't a problem on my Ubuntu machine.

Sorry for the wild goose chase.