What is KSM in KVM?

Kernel same-page Merging (KSM), used by the KVM hypervisor, allows KVM guests to share identical memory pages. KSM allows for greater guest density of identical or similar guest operating systems by avoiding memory duplication. The concept of shared memory is common in modern operating systems.

What is KSM sharing?

KSM (kernel samepage merging) is a Linux kernel feature that allows the KVM hypervisor to share identical memory pages among different process or virtual machines on the same server. This level of overcommitment is possible because virtual machines on the same host often share many duplicate memory pages.

What is Ksmtuned process Linux?

ksmtuned is part of Kernel same-page Merging (KSM) service, it’s a Linux feature used by KVM hypervisor, it examines the memory allocated by the running programs, if it finds identical memory pages it will merge them in a single memory page, the thing will reduce the used memory pages and hence the overall memory …

What is Linux KSMD?

The KSM daemon ksmd periodically scans those areas of user memory which have been registered with it, looking for pages of identical content which can be replaced by a single write-protected page (which is automatically copied if a process later wants to update its content).

What is KSM sharing proxmox?

KSM. KSM (Kernel Samepage Merging) is running in the Linux kernel and scans the memory of all the virtual machines running on a single host, looking for duplication and consolidating. With KSM we’re able to improve virtual machine density by as much as 300\% without impacting performance.

What is Khugepaged?

Khugepaged controls A higher value can cause excessive swap IO and waste memory. A lower value can prevent THPs from being collapsed, resulting fewer pages being collapsed into THPs, and lower memory access performance.

How much RAM does proxmox use?

2 GB
Memory, minimum 2 GB for OS and Proxmox VE services. Plus designated memory for guests. For Ceph or ZFS additional memory is required, approximately 1 GB memory for every TB used storage.

What is ballooned memory?

In computing, memory ballooning is a technique used to eliminate the need to overprovision host memory used by a virtual machine (VM). Depending on the amount of memory required by the VM, the size of the “balloon” may be increased or decreased dynamically, mapping and unmapping physical memory as required by the VM.

What is the difference between HugePages and transparent huge pages?

Transparent Hugepages are similar to standard HugePages. However, while standard HugePages allocate memory at startup, Transparent Hugepages memory uses the khugepaged thread in the kernel to allocate memory dynamically during runtime, using swappable HugePages.

How do I get rid of large transparent pages in Linux?

To disable Transparent HugePages:

1. For Oracle Linux 7 and later, and Red Hat Enterprise Linux 7 and later, add or modify the transparent_hugepage=never parameter in the /etc/default/grub file: Copy transparent_hugepage=never.
2. Run the grub2–mkconfig command to regenerate the grub.

Does Proxmox require Vt D?

Intel EMT64 or AMD64 with Intel VT/AMD-V CPU flag. Memory, minimum 2 GB for OS and Proxmox VE services. Redundant Gbit NICs, additional NICs depending on the preferred storage technology and cluster setup – 10 Gbit and higher is also supported. For PCI(e) passthrough a CPU with VT-d/AMD-d CPU flag is needed.

Can I run Proxmox from USB?

Now you can use the USB thumb drive to install Proxmox on your computer.

What is Kernel SamePage Merging (KSM)?

KSM is a memory-saving de-duplication feature, enabled by CONFIG_KSM=y, added to the Linux kernel in 2.6.32. See mm/ksm.c for its implementation, and http://lwn.net/Articles/306704/ and https://lwn.net/Articles/330589/ The userspace interface of KSM is described in Kernel Samepage Merging

What does KSM stand for in Linux?

Kernel Same-page Merging (KSM) Kernel same-page Merging (KSM), used by the KVM hypervisor, allows KVM guests to share identical memory pages. These shared pages are usually common libraries or other identical, high-use data. The concept of shared memory is common in modern operating systems.

What happens when KSM is set to 0?

When set to 0, ksm merges only pages which physically reside in the memory area of same NUMA node. That brings lower latency to access of shared pages. Systems with more nodes, at significant NUMA distances, are likely to benefit from the lower latency of setting 0.

What is the maximum number of KSM page sharers allowed?

Maximum sharing allowed for each KSM page. This enforces a deduplication limit to avoid high latency for virtual memory operations that involve traversal of the virtual mappings that share the KSM page. The minimum value is 2 as a newly created KSM page will have at least two sharers.

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