Limiting the usage of a resource (memory, disk space, CPU time, open files, network bandwidth, …) by a process or a group of processes.

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2
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1answer
72 views

starts logging when the limits are hit

/etc/security/limits.conf. The file is responsible to limit resources of users/groups on a Linux server. Unfortunately, the file does not generate any logs (or the case could be that I do not really ...
1
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0answers
133 views

Limiting the total size of samba's vfs_recycle by pruning oldest deleted files first

Running SerNet Samba 4.0.9 on CentOS 6.4 serving as an AD DC and fileshare for XP clients. Added recycler per the example here. My concern is that the recycle dir will eventually grow large. ...
0
votes
1answer
220 views

No virtual memory (-v) item in output of ulimit -a

When I run command ulimit -a, I see no virtual memory item in the list of output of the command. It is unlimited for some user IDs though. Does that mean I am assigned no virtual memory?
5
votes
2answers
621 views

Does linux kill heavy and long running background processes after they reach some threshold?

If I start a really heavy (memory/cpu intensive) running really long running process will the OS terminate it after a period of time arbitrarily? I.e. are there any limits beyond which the OS would ...
2
votes
0answers
44 views

equivalent to 'cpusets' for gpu's

I work with clusters of computers and manage the nodes with torque and Moab. A user is able to submit a job to a node, and request the amount of resources they need. #The following submits the job ...
6
votes
1answer
4k views

How to circumvent “Too many open files” in debian

If I want to see all relevant log files of my apache2 server at once, I use tail -f /var/kunden/logs/*log /var/kunden/logs/*log /var/log/apache2/*log |grep -v robots|grep -v favicon But since those ...
3
votes
2answers
3k views

sudo: ulimit: command not found

I was using ubuntu 12.04 ,on which I run ulimit -n ,it is showing 1024, I want to increase my open file limit from 1024 to 65535,so I tried the following command: sudo ulimit -n 65535 but i get the ...
4
votes
3answers
1k views

limiting size of logfile from a variable

How can I limit the size of a log file, which is saved in the form of 'foo.txt', from within a bash script please? I want to put in the variables 'LOGFILE=50 mb' and it uses that size, or whatever ...
0
votes
5answers
4k views

SSH login attempts per minute per IP

How can i limit SSH login attempts per minute per IP ? I want to disable login attempts during 5 seconds after a failure. Is this possible ? I'm not talking about ban a user after parsing logs like ...
5
votes
2answers
223 views

Externaly limiting number of CPU cores used

I need to externally limit a process/session to a certain number of cores. Are there any other possibilities than CPU affinity (I don't like the need to specify the actual cores) and cgroups (hard to ...
21
votes
3answers
1k views

Can the “du” program be made less aggressive?

We have a regular job that does du summaries of a number of subdirectories, picking out worst offenders, and use the output to find if there are things that are rapidly rising to spot potential ...
4
votes
2answers
9k views

Modify ulimit (open files) of a specific process

Is it possible to change the soft - and hard limit of a specific process? In my case, my process is mongod and a lot of web resources tell me to simply execute: ulimit -n <my new value> My ...
5
votes
1answer
2k views

How many users does Linux support being logged in at the same time via SSH?

I know Linux supports multiple users being logged in at the same time. But what's the maximum number of users that can be logged into Linux at the same time? I see there are there are 69 tty files ...
1
vote
2answers
122 views

understanding how to run script securely as limited user

I'm a long time dev but linux newbie. I've been building this (http://tryperl.com) to learn linux. So, my question is just about some *nix stuff I don't fully grok. One of the things I want to do is ...
3
votes
1answer
707 views

Httpd : no space left on device

I am using Fedora 17 and over the last few days I am having an issue with my system. Whenever I try to start httpd it shows me: Error: No space left on device When I execute systemctl status ...
9
votes
2answers
684 views

How to solve this memory issue gracefully?

I have a standard Linux (Debian testing) laptop, with a swap partition. I do a lot of experiments with it. Some of them are really memory hungry and the way Linux behaves by default is an issue for ...
5
votes
2answers
1k views

What is “automatic stack expansion”?

getrlimit(2) has the following definition in the man pages: RLIMIT_AS The maximum size of the process's virtual memory (address space) in bytes. This limit affects calls to brk(2), mmap(2) and ...
2
votes
0answers
120 views

Can I limit the number of inotify watches available to a process or cgroup?

I am consistently running out of inotify resources, leading to errors along the lines of: # tail -f /some/files tail: inotify resources exhausted tail: inotify cannot be used, reverting to polling ...
3
votes
1answer
432 views

Can I limit connections per second for certain UserAgents using UFW?

GoogleBot is hitting my server hard - and even though I have set the CrawlRate in Webmaster Tools it is still hiking up the load on my server and slowing down Apache for the rest of the normal web ...
2
votes
1answer
12k views

How to modify ulimit for open files on SUSE Linux Enterprise Server 10.4 permanently?

SERVER:/etc # ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited file size (blocks, -f) unlimited pending signals (-i) 96069 ...
1
vote
1answer
653 views

How to avoid 4 core limit for Ubuntu within VMWare?

I have Ubuntu installed as VM on my laptop. My laptop has quad core with HT technology making it 8 cores. Within Ubuntu VM I can only use max of 4 cores. What should I do so I can access all 8? ...
8
votes
1answer
2k views

Are limits.conf values applied on a per-process basis?

I'm tuning the nofile value in /etc/security/limits.conf for my oracle user and I have a question about its behavior: does nofile limit the total number of files the user can have open for all of its ...
3
votes
3answers
983 views

Can't add large number of rules to iptables

I made a very simple bash script (echo at start, runs commands, echos at end) to add approx 7300 rules to iptables blocking much of China and Russia, however it gets through adding approximately 400 ...
3
votes
1answer
648 views

How do you increase MAXSYMLINKS

In a python script, I am creating a bunch of symbolic links chained together. example: link1->link2->link3->.......->somefile.txt I was wondering how you can change the max number of symlinks to be ...
1
vote
0answers
763 views

Permanently change per-process stack size

When I use ulimit -s to change the per-process stack size, it only lasts for that login; if I restart the setting is lost. How can I permanently change the maximum stack size on my system?
4
votes
2answers
4k views

How to limit ftp speed

I have multiple users on a server. They upload and download their files through FTP. Sometimes some heavy transfer causes high load on the server. I am wondering, if there is any way to limit the ftp ...
11
votes
2answers
7k views

How to Throttle per process I/O to a max limit?

I'm looking for a way to limit a processes disk io to a set speed limit. Ideally the program would work similar to this: $ limitio --pid 32423 --write-limit 1M Limiting process 32423 to 1 megabyte ...
2
votes
2answers
146 views

How to constrain the resources an application can use on a linux web server

This is the situation: I have a PHP/MySQL web application that does some PDF processing and thumbnail creation. This is done by using some 3rd party command line software on the server. Both kinds of ...
7
votes
2answers
712 views

What is a canonical way to find the actual maximum argument list length?

Following ARG_MAX, maximum length of arguments for a new process it seems like ARG_MAX is wrongly (or at least ambiguously) defined on my Mac Mini 3,1 running Ubuntu 12.04: $ getconf ARG_MAX # ...
12
votes
2answers
1k views

Is there an upper limit to the number of zombie processes you can have?

I used to work with an HP-UX system and the old admin told me there is an upper limit on the number of zombie processes you can have on the system, I believe 1024. Is this a hard fact ceiling? I ...
7
votes
4answers
5k views

Preventing tar from using too much CPU and disk (old laptop crashes if 100%)

I want to backup 1 terabyte of data to an external disk. I am using this command: tar cf /media/MYDISK/backup.tar mydata PROBLEM: My poor laptop freezes and crashes whenever I use 100% CPU or 100% ...
17
votes
3answers
684 views

Limiting a specific shell's internet bandwidth usage

I want update my linux in one shell but by default wget or axel in updater use all the bandwidth. How can I limit the speed in this shell? I want other shells to have a fair share, and to limit ...
2
votes
3answers
836 views

How can I read lines at a fixed speed?

I need to read a large log file and send it over a local network using (netbsd) netcat between two VMs on the same host workstation. I know that netcat has an interval, but as far as I can tell, the ...
7
votes
1answer
2k views

Throttling web crawlers

My website is being DoS'ed by Google webspiders. Google is welcome to index my site, but sometimes it is querying a tagcloud on my site faster than my webserver can produce the results, making my ...
20
votes
3answers
19k views

Why is number of open files limited in Linux?

Right now, I know that: Find open files limit per process: ulimit -n Count all opened files by all process: lsof | wc -l Get maximum open files count allowd: cat /proc/sys/fs/file-max My ...
14
votes
2answers
15k views

How to create a user with limited RAM usage?

So I have 4 GB RAM + 4GB swap. I want to create a user with limited ram and swap: 3 GB RAM and 1 GB swap. Is such thing possible? Is it possible to start applications with limited RAM and swap ...
5
votes
2answers
4k views

ulimit PICKLE: “Operation not permitted” and “Command not found”

I'm trying to increase the maximum number of open files for the current user > ulimit -n 1024 I attempt to increase and fail as follows > ulimit -n 4096 bash: ulimit: open files: cannot ...
8
votes
2answers
6k views

How to limit available virtual memory per process

Occasionally some processes on my GNU/Linux desktop (such as gv and gnash) use up the physical memory and cause thrashing. Since these processes aren't important, I want them to be automatically ...
5
votes
1answer
236 views

Why is the following command killing a system?

Anyone understand the following code , running in bash ? :(){ :|:& };: It seems to be a "fork" bomb on Linux.
20
votes
2answers
20k views

Limit process to one cpu core

How to limit process to one cpu core ? Something similar to ulimit or cpulimit would be nice. (Just to ensure: I do NOT want to limit percentage usage or time of execution. I want to force app (with ...
8
votes
4answers
8k views

How do I limit the number of files printed by ls?

Is there a way to limit the quantity of listed files on a ls command? I've seen: ls | head -4 but to get head to be executed I need to wait for ls to finish execution, and with directories with an ...
10
votes
6answers
9k views

How to limit log file size using >>

How can I limit the size of a log file written with >> to 200MB? $ run_program >> myprogram.log
5
votes
1answer
1k views

File descriptor limits are lost after a system reboot

I'm trying to increase the default file descriptor limits for processes on my system. Specifically I'm trying to get the limits to apply to the Condor daemon and its sub-processes when the machine ...
22
votes
4answers
2k views

How to limit resource usage to save CPU+RAM for a certain process?

I have a dev server on which sshd sometimes stops working because the machine runs out of RAM. Yes we are running low on memory and upgrading is not a feasible choice right now. What I want to do is ...
3
votes
1answer
6k views

How do I increase the number of semaphore arrays in Linux?

In a Debian lenny server running postgresql, I noticed that a lack of semaphore arrays is preventing Apache from starting up. Looking at the limits, I see 128 arrays used out of 128 arrays maximum, ...
4
votes
1answer
832 views

Linux - why is kernel.shmall so low by default?

I run DB2 on Linux where I have to allocate the vast majority of memory on the machine to shared memory segments. This page is typical of the info that I've found about shmall/shmmax: ...
5
votes
2answers
5k views

Set default nice value for a given user (limits.conf)

Could someone tell me how to set the default value of nice (as displayed by top) of a user? I have found that /etc/security/limits.conf is the place but if I put either: username_of_a_guy - nice ...
13
votes
3answers
3k views

Can I limit a process to a certain amount of time / CPU cycles?

We have a script which runs on our web servers, triggered by customer action, which initiates a unix process to generate some cache files. Because this process acts upon files supplied by our ...
16
votes
6answers
6k views

Is there a way to limit the amount of memory a particular process can use in Unix?

I need to test a process for memory management. I do not have the source, so I need to do all the testing from the OS side. I want to be able to say something like limitmemory 400k -p <pid> ...
9
votes
6answers
2k views

How do I set a limit on the number of files Linux can have open?

I plan to run a Java app using nohup ... &. The limit must apply to commands like this.