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I've just upgraded the OpenSSH server version on my VPS from 4.3 to 5.8. For a reason each SSH session I make takes now at least 40MB Ram (It took 3-4MB before the upgrade).

My VPS has only 64MB Ram so I really need that ram, and can't find a reason how the ram usage came up by 1000%. OpenSSH is not that RAM-intensive.

The weird thing is when I try to open a SSH-1 session, it takes only 2MB ram, which is fine. Problem is that SSH-1 is not secure enough.

How can I debug the problem, or how can I get it fixed?

I'm using Debian 4 (etch).

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Is this a specialized VPS? If not, you may want to consider another VPS hosting service. Rackspace Cloud Servers comes to mind... 256MB memory for about $10/mo. – Matt Beckman May 5 '11 at 18:21

Try using pmap

pmap -x <pid_of_ssh>

"pmap - report memory map of a process"

This will list all the in memory objects in use by the process.

----------------  ------  ------  ------
total kB           90168    3284     732

the RSS (resident set size) is what you are interested in, although this does show a memory usage of 90168 kB a lot of that is shared,

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I have no RSS. Here is the log: – Alex58 May 3 '11 at 11:59

Dropbear is a relatively small SSH 2 server and client. It runs on a variety of POSIX-based platforms. Dropbear is open source software, distributed under a MIT-style license. Dropbear is particularly useful for "embedded"-type Linux (or other Unix) systems, such as wireless routers.

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