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eddyP23's questions

Martin Hope
eddyP23
Asked: 2016-04-16 09:55:44 +0800 CST
  • 3

I am trying to overwrite some directories with content in them on a remote location using pscp to a remote location. I use root user (root@locationServerName). It succeeds in most of them, but fails in some of them returning $? = 1.

The output of the command looks like that:

Sending file filename1.txt, size=2990
filename1.txt             |          2 kB |   2.9 kB/s | ETA: 00:00:00 | 100%
Sending file filename2.txt, size=2665135
filename2.txt: unable to open /path/to/file/location/filename2.txt: failure
Sending file filename3.txt, size=2990
filename3.txt             |          2 kB |   2.9 kB/s | ETA: 00:00:00 | 100%

It looks like for some reason it can't overwrite the files, but I can't figure why or how could I fix it. Running it in verbose mode, doesn't say anything helpful. If I delete the files manually on the target location, then the operation succeeds.

Any ideas?

copying centos6.5
Martin Hope
eddyP23
Asked: 2016-03-08 07:51:28 +0800 CST
  • 2

I have a server instance on an OpenStack that at a pretty high load starts loosing UDP packets. I captured all outgoing packets using tcpdump and some of them are missing, even though application logs imply that they should have been sent. Usual packet size is around 60-120 bytes.

Running netstat -s gives:

[root@myServer] ~> netstat -s | grep Udp: -A 5
Udp:
    3855490640 packets received
    133199 packets to unknown port received.
    89 packet receive errors
    4116940753 packets sent
    SndbufErrors: 1396176

When the server is under load, SndbufErrors keeps increasing. I tried to figure out what might be causing it but with no luck even though it feels like this should be covered somewhere.

Q: What might be the reasons for this and how could I resolve this?

Investigation I've done:

  1. Running ifconfig -a doesn't show any errors:

      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  RX packets:6361554048 errors:0 dropped:0 overruns:0 frame:0
  TX packets:6902945025 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:1000

    I tried increasing txqueuelen to 10'000 (by running ifconfig eth1 txqueuelen 10000), but it didn't make a difference.

  2. Running several sysctl commands I get:

    net.core.rmem_max = 124928
net.core.wmem_max = 4194304
net.core.rmem_default = 124928
net.core.wmem_default = 124928

    I tried increasing net.core.rmem_max and net.core.wmem_max to much bigger number 16'777'216, but still keep getting the same errors.

  3. Running sar -n UDP 1 1 gives (approximated values, but no errors):

    05:47:31 PM    idgm/s    odgm/s  noport/s idgmerr/s
05:48:46 PM  23000.00  24000.00      0.00      0.00

  4. Running ethtool on the Openstack VM instance mostly results in Operation not supported. Running ethtool on the Openstack host server choosing its interface that is used to communicate with outside world, I get:

    [root@myServer] ~> ethtool em1
    Speed: 1000Mb/s
    ... 

[root@myServer] ~> ethtool -g em1
    Ring parameters for em1:
    Pre-set maximums:
    RX:             4096
    RX Mini:        0
    RX Jumbo:       0
    TX:             4096
    Current hardware settings:
    RX:             256
    RX Mini:        0
    RX Jumbo:       0
    TX:             256

    I am not convinced that it can be related though as errors I see are inside the VM and not the Openstack host server. Update: I increased the RX and TX values, but to no success.

centos6