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Ubuntu 10.04 64bit - Kernel 2.6.36 Running as a Xen 3.4 guest.

8GB memory , no swap being used, no IO wait time, and 0% cpu. Yet high load. Why is this:

15:11:24 up 5 days,  3:22,  2 users,  load average: 21.23, 20.06, 19.51
Tasks: 113 total,   1 running, 112 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:   7416372k total,  5250472k used,  2165900k free,   153260k buffers
Swap:  1959924k total,    26288k used,  1933636k free,   246932k cached

IO top shows nothing.

free -mem

        total       used       free     shared    buffers     cached
Mem:          7242       5127       2115          0        149        241
-/+ buffers/cache:       4736       2506
Swap:         1913         25       1888
share|improve this question
Presumably you have a lot of threads/processes waiting for I/O that's not happening. Networked filesystems can do this. – David Schwartz Sep 24 '12 at 19:39
Have you got 4 CPUs? – Nils Sep 24 '12 at 20:51
Dual Xeon - 8 threads. – Tom C Sep 24 '12 at 21:06

You either 1) own the host or 2) you are renting it from a hosting company.

If it's 1 then you should look at the other machines on the host, find out which one is thrashing the disks and fix it.

If it's 2 you need to complain to your hosting company and see if they can't either move you or move the offending party to another physical box and/or data store.

share|improve this answer
If 1 then there should be wait time. If 2 there should be stolen time. – Nils Sep 24 '12 at 20:53
It's on a 'bare-metal' Xen guest. Hosted with a provider. they say the physical hardware isn't shared. It's just under a Xen host to be able to launch/re seize, etc easily. – Tom C Sep 24 '12 at 21:08

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