Questions tagged [virtual-memory]
It is an extension of memory address space which is logically appended to the physical memory of a computer by the Memory Management Unit (MMU) of its processor. It is normally realized in operating systems by utilizing free disk space to implement such memory extension and may also be referred to as swap-file or page-file.
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Meaning of the buffers/cache line in the output of free
Why does my server show
total used free shared buffers cached
Mem: 12286456 11715372 571084 0 81912 6545228
-/+ buffers/cache: 5088232 7198224
Swap:...
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Caching/preloading files on Linux into RAM
I have a rather old server that has 4GB of RAM and it is pretty much serving the same files all day, but it is doing so from the hard drive while 3GBs of RAM are "free".
Anyone who has ever tried ...
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swap partition vs file for performance?
What is better for performance? A partition closer to the inside of the disk will have slower access times, and we must wait for the drive to switch between the OS and swap partitions.
On the other ...
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In Linux, what is the difference between "buffers" and "cache" reported by the free command?
This is an old question that I've seen from time to time. My understanding of it is rather limited (having read about the differences a long time ago, but the factoid(s) involved never really stuck).
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How do I tell what process is causing kswapd to be in use?
I see kswapd using 100% CPU... how can I tell on which process's behalf kswapd is being used so much?
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Difference Between Private Memory Limit and Virtual Memory Limit in IIS
I want to set the max limit on the physical memory an application can use in IIS 7.
Should I set a limit on Private Memory Limit or Virtual Memory Limit?
Can some one point me to documentation of all ...
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What is "a lot" of Page Faults?
I am monitoring the memory object in Windows 2k8, and am tracking the Page Faults/sec counter. Is there any threshold to determining what is an excessive amount of page faults? Or should I be more ...
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How to limit the memory used by an application in IIS?
The IIS worker processes are taking lot of memory on our servers. I want to limit the memory each application can use. I am confused whether I should set a limit on Virtual Memory Limit, or Private ...
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Constantly Increasing swap size in Linux and Swap space not being reclaimed?
I have a 8GB RAM linux box on which 4 tomcat servers are running. One of the them is set to 3000MB memory(jvm -Xms and -Xmx setting) and others are set to 1500MB. The swap partition is also set to ...
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How to sort top result on virtual memory on Redhat Linux?
There is an interactive key "M" to sort by memory, which seems to be sorting on resident memory. Is there a way to sort on virtual memory? I happen to be working on Redhat Linux, but the question is ...
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Understanding virtual memory usage > swap + physical on Linux
I have a process that is reporting in 'top' that it has 6GB of resident memory and 70GB of virtual memory allocated. The strange thing is that this particular server only has 8GB physical and 35GB of ...
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Ballooning occuring on SQL server
From what I understand ballooning should occur only when the host begins to run out of physical memory, somewhere above 90% usage. I have an SQL server running in a three node cluster (64 GB RAM in ...
user35213
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How do you measure the memory footprint of a set of forked processes?
Say I've got a process using 200MB of memory, and it fork()s:
python -c "import os; data='x'*200000000; os.fork(); raw_input()"
Programs like 'top' will show each process using 200MB, with very ...
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Linux OOM disk I/O. Also: swap, what is it good for?
I'm having problems with the OOM killer on one of my Linux (2.6.37) installs. The computer has 4GB of memory which I sometimes utilize fully. In those cases, I expect the OOM handler to come in and ...
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What are the exact conditions based on which Linux swaps process(s) memory from RAM to a swap file?
My server has 8Gigs of RAM and 8Gigs configured for swap file. I have memory intensive apps running. These apps have peak loads during which we find swap usage increase. Approximately 1 GIG of swap is ...
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Memory overcommitment on VMware ESXi 5.0
I would like to understand better the possibilities of VmWare ESXi memory overcommitment. I've read this paper from VmWare, so I am familiar with general concepts, such as hypervisor swapping, memory ...
user81458
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What is nonpaged pool?
I have a Server 2008 R2 that I maintain on a day-to-day basis.
The server is good and operating fine but it keeps sending me event 2019 error logs.
"The server was unable to allocate from the system ...
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Different linux page cache behavior for servers doing the same work
I have two sets of servers w/128G memory, distinguished by when they were provisioned, that are behaving very differently while running the exact same daemon (elasticsearch). I am using elasticsearch ...
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Automatically suspend/hibernate a process when too much memory taken
I'm running a small Debian compute cluster on 8-core PCs with 16GB of RAM. I'm running batches of about 1k tasks (each batch has a total expected time of a month to be finished). A single task is ...
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Is it possible to set vm.overcommit_memory =1 only for specific containers?
So, I'm running a container that is showing this in the log:
WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = ...
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What is the default maximum value for /proc/sys/kernel/shmmax
I am having an amiguity as to what the maximum value in shmmax should be set.
After having a look at my system's statistics, it shows the following:
#cat /proc/sys/kernel/shmmax
...
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Is it bad if your Virtual Bytes count is high in an application pool in IIS?
Related to What does Virtual Bytes mean in Worker Processes pane in IIS7.5 Manager?
I have a server running a few different sites. We're seeing some performance and memory issues.
When I go to ...
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Why does Windows Server 2012 R2 Standard edition show only 20% of my available memory?
Fellow Techies-- I have a LENOVO x3650 X6/x64 based Windows server with 4 18 cores/36 logical processors-- with installed physical memory (ram) @1.5 TB, total virtual memory @1.5 TB. However, I am ...
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Windows Server task manager displays much higher memory use than sum of all processes' working set size
I have a 16 GB Windows Server 2008 x64 machine mostly running SQL Server 2008. The free memory as seen in Task Manager is very low (128 MB at the moment), i.e. about 15.7 GB are used. So far, so good.
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Sleepless
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How can I keep important VMs in memory without disabling swap?
VM Host -> Xenon E5-2440 w/ 48G mem... Everything runs CentOS6.5 (2.6.32-431)
I have 4 guest VMs running each w/ 2G of memory. Their disk images are local files.
The host machine is also running a ...
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Mysql using high VIRT memory and RES is compartively
is there a way to reduce the VIRT mem usage?
I am not sure what the reason is for such high usage.
It has reached upto 12g as well.
Using top command
Tasks: 348 total, 1 running, 344 sleeping, 0 ...
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Virtualization limits for Ubuntu Server 14.04 LTS with KVM?
Essentially I'm after something like this:
Virtualization limits for Red Hat Enterprise Linux with KVM
but for Ubuntu Server 14.04 LTS.
I'm trying to create some KVM guests with very large 1TB+ RAM ...
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Linux max. value for vm.max_map_count
I'm planning to increase significantly the default value of 65k max mappings; let's say multiply by 10. Assuming we have enough memory on the machine is there anything I should take care of doing that?...
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How can I measure disk cache churn on Linux? [duplicate]
Possible Duplicate:
Is there a way to get Cache Hit/Miss ratios for block devices in Linux?
I have a file server which serves out large (25GB-1TB+) files over the network from local storage. I'm ...
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Linux OOM-killer acting despite plenty available memory
Once a week or so the OOM-killer shoots down a postgres process in my server, despite that 'free' states it has plenty of available memory.
I have read several threads here and there, but cant see ...
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How do I find the root cause of Memory pressure failure on an SQL server 2008?
One of the servers I have been performance monitoring started throwing the following warnings from the Resource-Exhaustion-Detector:
Windows successfully diagnosed a low virtual memory condition. ...
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Virtual Server Memory not a power/multiple of 2
In the old times (before virtualization), memory came in powers/multiples of 2, because that is the way memory is manufactured. Nowadays that we create virtual servers that don't have real physical ...
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Windows Server 2016 pagefile does not increase
I apologize in advance if this is not clear enough to understand my problem, it's a bit long but I've done my best to make it understandable.
I'm running an Exchange 2016 CU6 on a Windows server 2016 ...
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High Memory 64bit server, not using all ram
I have several high memory linux servers running centos 64bit, and after 10-20 days of uptime I have noticed on all of these servers they dont actually use all the ram available to then (they all have ...
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Does z/OS enforce memory protection between processes of the same user?
It is often pointed out that each user has their own (virtual) address space in in z/OS; this is said as if it is a good thing, and I suppose it is compared to real mode. But in most modern systems I'...
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What is shrink_slab, and why is it showing up in /var/log/messages?
I'm investigating some application issues on a Linux system and noticed this around the time of the most recent problem, but not close enough to be definitively related:
Jun 7 17:51:49 localhost ...
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Reducing Virtual memory Page File Size on Windows 7
I've upgraded my PC to 16GB RAM and I've noticed the page file is at 16GB as well. Since I decided to go SSD, hard drive space is a bit limited so I would like to try and claim some of that 16GB back.
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Performance effects of compressing Program Files on Windows / NTFS
What are the performance effects of compressing Program Files on Windows NTFS?
On a fast, multicore machine, the overhead of decompression is minimal. Machines are generally disk bound, and if you ...
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Running out of memory, or running out of disk space?
I'm running a database loading process (osm2pgsql) which is failing:
Processing: Node(17404k 148.8k/s) Way(1351k 6.38k/s) Relation(9520 29.94/s)way_done failed: ERROR: could not extend file "base/...
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Large virtual memory size of ElasticSearch JVM
I am running a JVM to support ElasticSearch. I am still working on sizing and tuning, so I left the JVM's max heap size at ElasticSearch's default of 1GB. After putting data in the database, I find ...
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How to tune system settings for mongoDB on Linux?
Trying to squeeze a lot out of one question here -- please bear with me.
Although the MongoDB man pages make several useful recommendations about system settings like ulimit (http://docs.mongodb.org/...
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Windows Server: Prevent process swapping/paging
Is there a possibility to prevent swapping for a single process?
This process is an in-memory-database and should not be moved to virtual ram.
all other processes should still be swap-able.
I ...
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Running out of memory with plenty of memory and swap
I have a Debian-based system that is running out of memory but there appears to be plenty of free memory. The box will run for about 6-12 days and then it will begin killing anything allocating memory ...
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Slab reclaimable memory is not freed when needed
Correct me if I am wrong, but to my understanding slab reclaimable holds cached kernel objects which can be freed if needed. So if application needs to allocate more space, even if the 'free' memory ...
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How to interpret increasing SHR reported by top?
The man page for top defines SHR as:
t: SHR -- Shared Mem size (kb) The amount of shared memory used by a
task. It simply reflects memory that could be potentially shared with
other ...
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virtual memory commited
After a server bounce happens, and after around 40-45 days time period, we receive continuous “Committed Virtual Memory” alerts which indicates the usage of swap space in the magnitude of >4GB
This ...
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Linux virtual memory tuning to workaround disk I/O issue
I am having a problem with a Linux server that it is writing to much to disk, thus I am having a slow response time due to a big IO wait. I already check smart values for the disks and are OK. This is ...
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Linux out of memory on VPS
On my VPS (CentOS) 4GB ram (2 + 2 dynamically assigned when needed) and i have tomcat running with following options JAVA_OPTS="-Xms256m -Xmx2048m -XX:MaxPermSize=256m".
Now when i try to start ...
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Remove swap completely or set swappiness to 0?
In managing a server with 512GB of RAM I encountered a process that keeps consuming swap until it hits 100% of the swap space then stops consuming more (6GB of swap) but keeps working fine (albeit, ...
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Committed/Allocated memory in Linux is less than used memory. How is that possible?
So I have a system with linux kernel 4.14.73 in which I am using values from /proc/meminfo in an program that shows the system specs including memory used and memory reserved. All was well until I saw ...
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