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Questions tagged [limit]

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

139
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5answers
282k views

do changes in /etc/security/limits.conf require a reboot?

do changes in /etc/security/limits.conf require a reboot before taking effect? Like if I have a script that sets the following limits in /etc/security/limits.conf, does this require me to reboot ...
128
votes
3answers
169k 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 question ...
78
votes
7answers
124k 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 or tail to be executed I need to wait for ls to finish execution, and with directories ...
65
votes
2answers
72k views

How to limit a process to one CPU core in Linux? [duplicate]

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 ...
37
votes
3answers
62k 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 ...
36
votes
3answers
89k views

Limit max connections per IP address and new connections per second with iptables

We have an Ubuntu 12.04 server with httpd on port 80 and we want to limit: the maximum connections per IP address to httpd to 10 the maximum new connections per second to httpd to 150 How can we do ...
36
votes
7answers
33k views

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

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> Is ...
35
votes
3answers
51k views

Creating threads fails with “Resource temporarily unavailable” with 4.3 kernel

I am running a docker server on Arch Linux (kernel 4.3.3-2) with several containers. Since my last reboot, both the docker server and random programs within the containers crash with a message about ...
31
votes
7answers
50k views

Limiting processes to not exceed more than 10% of CPU usage

I operate a Linux system which has a lot of users but sometimes an abuse occurs; where a user might run a single process that uses up more than 80% of the CPU/Memory. So is there a way to prevent ...
30
votes
4answers
34k 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 ...
30
votes
5answers
105k views

How can I increase open files limit for all processes?

I can use ulimit but I think that only affects my shell session. I want the limit increased for all processes. This is on Red Hat.
25
votes
8answers
15k views

Make disk/disk copy slower

Is there a method of slowing down the copy process on Linux? I have a big file, say 10GB, and I'd like to copy it to another directory, but I don't want to copy it with full speed. Let's say I'd like ...
25
votes
4answers
3k 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 ...
23
votes
4answers
56k 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 ...
23
votes
8answers
41k 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
23
votes
1answer
14k 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 ...
22
votes
3answers
5k views

Practical limit on the number of btrfs snapshots?

I am considering using btrfs on my data drive so that I can use snapper, or something like snapper, to take time based snapshots. I believe this will let me browse old versions of my data. This would ...
21
votes
3answers
2k 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 ...
21
votes
3answers
1k 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 ...
21
votes
1answer
37k views

sudo: ulimit: command not found [duplicate]

On Ubuntu 12.04, I ran 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 following error: ...
19
votes
3answers
2k views

Get over 2 GB limit creating PDFs with ImageMagick

I am using convert to create a PDF file from about 2,000 images: convert 0001.miff 0002.miff ... 2000.miff -compress jpeg -quality 80 out.pdf The process terminates reproducible when the output file ...
18
votes
2answers
3k views

Why is socket path length limited to a hundred chars?

On Unix systems path names have usually virtually no length limitation (well, 4096 characters on Linux)... except for socket files paths which are limited to around 100 characters (107 characters on ...
17
votes
3answers
3k 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 ...
16
votes
3answers
6k 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 customer,...
15
votes
2answers
6k views

How to limit the total resources (memory) of a process and its children

There are plenty of questions and answers about constraining the resources of a single process, e.g. RLIMIT_AS can be used to constrain the maximum memory allocated by a process that can be seen as ...
14
votes
4answers
16k 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% ...
13
votes
2answers
13k 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 ...
13
votes
1answer
7k views

Terminal does not accept pasted or typed lines of more than 1024 characters [duplicate]

When I enter text on stdin in an OS X Terminal, a single line is limited to 1024 characters. For example, cat > /dev/null beeps after I type (or paste) a line longer than this, and refuses to ...
12
votes
2answers
5k 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 mremap(...
11
votes
3answers
47k views

Number of SSH connection(s) on a single linux machine

I landed up in a situation wherein I had to access a Linux machine via puTTY.I made various attempts to SSH but failed to connect to the machine. I then realised my colleague was accessing the same ...
11
votes
2answers
13k 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 ...
11
votes
2answers
22k views

How to limit available virtual memory per process [duplicate]

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 ...
11
votes
2answers
3k views

How can I allow a user to prioritize a process to negative niceness?

I want a user to run a specific process on the system with a negative nice value. I can't simply fork the process to background as this specific program is a minecraft server and I rely on the command ...
11
votes
6answers
3k 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.
10
votes
2answers
6k views

receive signal before process is being killed by OOM killer / cgroups

In our cluster, we are restricting our processes resources, e.g. memory (memory.limit_in_bytes). I think, in the end, this is also handled via the OOM killer in the Linux kernel (looks like it by ...
10
votes
2answers
2k 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 ...
9
votes
1answer
39k 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 ...
9
votes
2answers
2k 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 # ...
9
votes
1answer
333 views

Do processes in cgroups have to be set every boot? If so, how to persist them?

I was reading this answer to a question on setting limits for processes by using cgroups. The sample given sets limits for a process (in the example, sshd). In the answer, the PID of the process is ...
9
votes
1answer
21k views

Fixing ulimit: open files: cannot modify limit: Operation not permitted

I tested this on different GNU/Linux installations: perl -e 'while(1){open($a{$b++}, "<" ,"/dev/null") or die $b;print " $b"}' System A and D The first limit I hit is 1024. It is easily raised ...
8
votes
1answer
19k views

How to configure the process open file limit of a user?

The default open file limit per process is 1024 on - say - Linux. For certain daemons this is not enough. Thus, the question: How to change the open file limit for a specific user?
8
votes
2answers
15k 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 ...
8
votes
1answer
5k 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 ...
8
votes
3answers
8k views

Largest allowed maximum number of open files in Linux

Is there a (technical or practical) limit to how large you can configure the maximum number of open files in Linux? Are there some adverse effects if you configure it to a very large number (say 1-...
8
votes
1answer
4k 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 ...
8
votes
1answer
803 views

Can you throttle the bandwidth to a tmpfs based ramdisk?

I created a ramdisk using tmpfs as follows: sudo mount -t tmpfs -o size=1024m tmpfs /myramdisk I was looking into cgroup blkio subsystem bandwidth limits "read_bps_device" and "write_bps_device" but ...
7
votes
1answer
2k views

What is the sense behind ZFS's limits?

According to Wikipedia, ZFS has the following limits: Max. volume size: 256 trillion yobibytes (2128 bytes) Max. file size: 16 exbibytes (264 bytes) Max. number of files: Per directory: 248 Per file ...
7
votes
1answer
7k 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 (...
7
votes
1answer
6k views

/dev/mmcblk0 partitions limit

I've just mounted a microSD card which has 17 partitions in my laptop and I'm getting the following error in the YaST partitioner: Your disk /dev/mmcblk0 contains 17 partitions. The maximum number of ...
7
votes
1answer
17k views

How to change the kernel max PID number? [duplicate]

The default PID max number is 32768. To get this information type: cat /proc/sys/kernel/pid_max 32768 or sysctl kernel.pid_max kernel.pid_max = 32768 Now, I want to change this number... but I ...