Why doesn't free memory go down on Linux?

Hello Friends,

I have a Linux OS with a java application using 2 GB on a whole and 1.5 GB Memory for oracle database on a 8 GB RAM machine. I am in a situation where i see free memory to be very low i.e. just 35 MB. I had a look at all the available processes but none of the processes are consuming so much memory which is missing. Do you think it is bug? No, it is a feature provided in Redhat Linux.

You can find a good explanation about the situation i have explained above in the below article.

http://sourcefrog.net/weblog/software/linux-kernel/free-mem.html

rstat daemon on Unix

Hello All,
Most of you might know that few times we see that LoadRunner doesn't collect OS metrics on Unix, this might be due to 2 reasons, rstatd was not configured or that daemon was not running on that machine. This is important standard performance meter to work.We can achieve this by doing the following.

rstatd prerequisites
Ensure that the rstatd daemon is running on the monitored computer by verifying the presence of the following entry in /etc/inet/inetd.conf
rstatd/2-4 tli rpc/datagram_v wait root /usr/lib/netsvc/rstat/rpc.rstatd rpc.rstatd

By default Solaris 5.10 disables it .
# svcadm enable rstat
to verfiy whether it is running, run rpcinfo -p

Location of rpc.rstatd can vary among different Operating systems.