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Just installed 64-bit Ubuntu Server 10.10 inside as guest in a virtual machine. I'm using VMware Player. The host is 64-bit Windows 7.

The minimum requirements for the Ubuntu server is said to be 128MB RAM.

So right after the install, I ran top command and to my surprise it said:

Tasks: 63 total, 1 running, 62 sleeping, 0 stopped, 0 zombie
Mem: 504088k total, 446192k used, 57896k free, 30548k buffers

From what I've read, modern Linux systems buffer memory for performance reasons. But here, only ~30.5MB is used for buffers.

I sorted based on %MEM and there's nothing that stands out (biggest hogger is at 1.3%). Is it because of the virtualization that the memory is some how pre-allocated and thus shown in the used field?


free -m
          total      used      free     shared     buffers     cached
Mem:        492       435        56          0          29        338
-/+ buffers/cache:     67       424
Swap:       563         0       563
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What does free -m say? – Cakemox Oct 15 '10 at 13:58
up vote 4 down vote accepted

From your free output, you're only using 67MB. The rest is used for buffers (29M) and filesystem cache (338MB).

share|improve this answer

Check out this page - it'll give you a better understanding of what's most likely going on:

Linux Ate My RAM!

share|improve this answer
Very concise link.. exactly to the point. I gave you an upvote, but will accept Cakemox's answer. Thanks! – randomguy Oct 15 '10 at 14:13

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