UNIX for Dummies Questions & Answers

When i first restart my computer memory usage is at 24% as the days months and evening pass it gets up to 80% and holds there sometime breaching 98%. Is there an command to regain the memory?


Redhat 8
768 mb ram

It sounds like you have runaway procs that are consuming your memory. As time goes on they take over more and more of your available memory as it is freed by other procs. You need to determine which procs are using the most memory and then decide to whether to kill and restart them.

I don't know what type of monitoring tools you have on Redhat, but i bet you do or can download a patch for one to read the performance on your host.

See this post.

Ok that was an answer and then some. Thank you very much for taking the time to expain it and to provide the ability for me to go go find the sources. I had done a search on memory on this sight and read that replay and many others but never quite found the answer i wanted.

thank you

FWIW: Linux uses memory very efficiently and will often, over time, use most of the memory available. This is considered to be a feature, BTW.

Take, for example, XP. I have 1.5GB loaded and it seems to never use more than 400MB - 500 MB no matter how many apps I have running.

If this was a linux system, it would find a way to use all the memory.

Your description of linux, over time, using 80 percent or more memory is common. Here is our linux server memory stats:

Code:

CPU states: 10.8% user,  6.1% system,  0.0% nice, 83.0% idle
Mem:   517496K av,  506932K used,   10564K free,   64624K shrd,  298040K buff
Swap:  256024K av,     320K used,  255704K free     111132K cached

Up almost 3 months:

Code:

www# uptime
  8:52pm  up 84 days, 21:36,  3 users,  load average: 0.15, 0.10, 0.05
www#

So, 507/517 is about 98 percent, and this is normal for good running linux boxes because linux is designed to use the available memory efficiently.

Both the answers have helped. I now atleast better understand the principle behind the numbers. My concern was because i am used to reading, now back words, the micro-soft way. My computer starts at 98% resources free and then works to 60% or 70%. If i run Maya a graphics render program then i can expect to drop even lower with my only recoil to restart. Similiarly the win2k server I manage has to be restarted one a month or so to keep it really happy.

So in conclusion. There is not an aplication or cammand i run to regain the mem % usage, nore should I focus on it relentlessly as it may not be causing as much of a problem as the numbers might seem.

I agree with your conclusions; and certainly don't worry that our linux server is at 98 percent memory usage. If I installed another 512 MB, it would still go to 98 percent because linux likes to use the available memory What's the point of having memory if the OS does not use it? ( or at least that is what I keep saying after loading my XP box to 1.5 GB and never using more than 400 - 500 MB, and being CPU bound most of the time in application resource time...)

If you are not seeing much swap activity, you are OK. If you are swapping (using the disks to supplement memory) then add more memory if you can.