I'm currently using a combination of qemu-kvm, libvirtd, and virt-manager to host some virtual RHEL 6 machines. When I go ahead and attempt to bump the ram usage up above 4gb, the machines fail to start. What would even be the cause of this? Any information is helpful.
I'm running a 10 core, 3GHz Xeon processor, with 64 GB of ram.
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We have a Data ware house server running on Debian linux ,We are using PostgreSQL , Jenkins and Python.
It's been few day the memory of the CPU is consuming a lot by jenkins and Postgres.tried to find and check all the ways from google but the issue is still there.
Anyone can give me a lead on how to reduce this memory consumption,It will be very helpful.
below is the output from free -m
total used free shared buff/cache available
Mem: 63805 9152 429 16780 54223 37166
Swap: 0 0 0
below is the postgresql.conf file
Below is the System configurations,
Results from htop
Please don't post text as images. It is hard to read and process.
I don't see your problem.
Your machine has 64 GB RAM, 16 GB are used for PostgreSQL shared memory like you configured, 9 GB are private memory used by processes, and 37 GB are free (the available entry).
Linux uses available memory for the file system cache, which boosts PostgreSQL performance. The low value for free just means that the cache is in use.
For Jenkins, run it with these JAVA Options
JAVA_OPTS=-Xms200m -Xmx300m -XX:PermSize=68m -XX:MaxPermSize=100m
For postgres, start it with option
-c shared_buffers=256MB
These values are the one I use on a small homelab of 8GB memory, you might want to increase these to match your hardware
When running Mongod I get the following WARNING: The file system cache of this machine is configured to be greater than 40% of the total memory. This can lead to increased memory pressure and poor performance. This is on a windows 10 pro 64 bit machine.
I got mongodb version 3.0 on linux redhat 6. The storage engine is MMAPv1.
I checked mongo memory usage on the server. I notice that virtual memory is 10 Gb which is far from mapped memory that is 4 Gb.
Is this situation correct or mongo server is running suboptimal?
It should be related to the glibc new virtual memory management since glibc2.10.
see here .
https://www.ibm.com/developerworks/community/blogs/kevgrig/entry/linux_glibc_2_10_rhel_6_malloc_may_show_excessive_virtual_memory_usage?lang=en
In a nutshell, the new malloc will allocate by default 8*cores*64MB on 64bit system for thread memory pool.
I have a cloud server in cloudways, the CPU load is very high even after I upgrade my server up 2 levels but the strange thing is the ram is almost free ( server 16 GB ram 6 Core) is there anything we can do to take advantage of that free ram to reduce CPU load.
Regards
No CPU and RAM are different things
Check the reason why your CPU is highly loaded.
Maybe your host where your VM runs on is overloaded. Did you try to
contact your cloud provider?
I was looking for an answear but didn't find one.
I'm trying to create a new VM to develop a web application. What would be the optimal processor settings?
I have i7 (6th gen) with hyperthreading.
Host OS: Windows 10. Guest OS: CentOS.
Off topic: RAM that should I give to VM should be 50% of my memory? Would it be ok? (I have 16GB RAM)
Thanks!
This is referred to as 'right-sizing' a vm, and it is dependent on the application workload that will run inside it. Ideally, you want to provide the VM with the minimum amount of resources the app requires to run correctly. "Correctly" is subjective based upon your expectations.
Inside your VM (CentOS) you can run top to see how much memory and cpu % is being used. You can also install htop which you may find friendlier than top.
RAM
If you see a low % of RAM being used, you can probably reduce what you're giving the VM. If you are seeing any swap memory used (paging to disk), you may want to increase the RAM. Start with 2GB and see how the app behaves.
CPU
You'll may want to start with no more than 2vCPUs, checkout top to see how utilized the application is under load, and then make an assessment for more/less vCPUs.
The way a hosted hypervisor (VMware Workstation) handles guest CPU usage is through a CPU scheduler. When you give a vm x number of vCPUs, the VM will need to wait till that many cores are free on the CPU to do 'work'. The more vCPUs you give it, the more difficult (slower) it will be to schedule. It's more complicated than this, but I'm trying to keep it high level. CPU scheduling deep dive.