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I have a 256 slice VM from Slicehost that is often incredibly slow to respond to key presses over ssh. It can take as long as 3 seconds to type "ls".

From what I can tell, my VM doesn't seem to be all that taxed for resources. So I am guessing that the problems are either my network connection to the VM or some other VM on the physical hardware impacting my server. How would I go about determining what the cause of the issue is?

Stats for my VM:

$ uptime
 08:44:47 up 98 days,  6:25,  1 user,  load average: 0.00, 0.00, 0.00
$ free -m
             total       used       free     shared    buffers     cached
Mem:           268        251         16          0          6         48
-/+ buffers/cache:        197         70
Swap:          511         14        497
$ top
top - 08:45:32 up 98 days,  6:25,  1 user,  load average: 0.07, 0.02, 0.00
Tasks:  82 total,   1 running,  81 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:    274540k total,   257688k used,    16852k free,     6436k buffers
Swap:   524280k total,    15320k used,   508960k free,    49532k cached

This is a traceroute from my local machine to the VM:

Hop Hostname    IP  Time 1  Time 2
1   my_pc.local 192.168.1.107   0.114ms 
1   router.local    192.168.1.1 1.887ms 
1   router.local    192.168.1.1 1.287ms 
2   no  reply   *   
3   no  reply   *   
4   be-51-ar01.needham.ma.boston.comcast.net    68.85.162.157   533.341ms   
5   pos-2-3-0-0-cr01.newyork.ny.ibone.comcast.net   68.86.90.57 422.463ms   
6   pos-0-12-0-0-cr01.ashburn.va.ibone.comcast.net  68.86.85.29 598.607ms   
7   pos-1-8-0-0-cr01.atlanta.ga.ibone.comcast.net   68.86.87.90 998.950ms   
8   pos-1-12-0-0-cr01.dallas.tx.ibone.comcast.net   68.86.85.157    1014.316ms  
8   pos-1-12-0-0-cr01.dallas.tx.ibone.comcast.net   68.86.85.157    479.281ms   
9   pos-0-2-0-0-pe01.1950stemmons.tx.ibone.comcast.net  68.86.86.150    963.164ms   
10  rackspace-bbr.dfw1.comcast.net  75.149.230.242  619.255ms   
11  core7-bbr1-vlan3007.dfw1.rackspace.net  174.143.123.118 359.844ms   
12  98.129.84.173   98.129.84.173   343.851ms   
13  my_slice    174.143.xxx.xxx 5082.621ms  

And a ping from my local machine to the VM:

Bytes    Source  Seq Time    Units
64  174.143.xxx.xxx 1   71.4    ms
64  174.143.xxx.xxx 2   73.3    ms
64  174.143.xxx.xxx 3   70.0    ms
64  174.143.xxx.xxx 4   72.3    ms
64  174.143.xxx.xxx 5   69.7    ms
Time minimum:   69.70 ms
Time average:   71.35 ms
Time maximum:   73.30 ms
Packets transmitted:    5
Packets received:   5
Successful packets: 100%

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2 Answers

up vote 3 down vote accepted

There's a problem with the virtual machine, as you can see from the traceroute, it's taking 6 seconds at the last hop, which is the virtual network for the vm.

Either it's a software issue in the guest OS (CPU too locked-up to reply in a timely manner) or on the host (not enough resources to virtualize the network with proper response times?). I'd suggest contact linode support, they're fairly good.

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Thanks, while contacting them, can you recommend any further analysis that I can do on this problem? Basically this is a learning project for me so the solution isn't as important as learning how to solve/identify. –  Rob Aug 1 '10 at 13:56
    
Try running top on the VM, see if anything is taking up an ungodly amount of CPU. –  Mahmoud Al-Qudsi Aug 1 '10 at 20:34
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Sounds like a network problem for me. What about ping my_slice?

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Added ping & updated traceroute stats –  Rob Aug 1 '10 at 13:56
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