Ubuntu Servers :: Consequences Of Giving PHP Scripts A High Memory Limit?
May 28, 2010
I have an Ubuntu server running in our small office. Among its many duties is report generation. It uses PHP and DOMPDF (a PHP library for converting HTML/CSS to PDFs for printing). PHP's default memory limit of 32MB is not even close to being enough to pull large amounts of data from the database and generate images/tables/PDFs with that data.
I increased the memory limit to 64MB and that is adequate for reports under 3 pages or so (varies based on table complexity, images, etc). If any user tries to generate a report longer than that, PHP just throws a "out of memory" error and doesn't make the report.
My question is: what are the possible consequences of increasing the memory limit yet again to 128MB or maybe even higher? The server isn't terribly powerful. It has 2GB RAM and 4GB swap space. I know that isn't much but this is a small office and at most I can only see two or three people trying to run reports at the same time. As for security, apache is currently only serving pages in the local network, but sometime within the next year I'll probably have it hosting a public website (currently using a hosting service). Is a high memory limit a potential security risk when exposed to the internet?
EDIT: Sorry, PHP's default memory limit is 16 not 32 as I said. Question still stands, however
I have a VPS server with 512 MB memory. The php.ini is set so script memory limit = 16 MB. However, I have noticed in my top report, instances like the following:
The bold number of 6.4 is the % of sever memory this process is using. 6.4 % of 512 MB of memory is about 32 MB of memory, so it appears that this isn't being limited by php.ini. Am I correct? This leads to the next question: Is there some way to limit the amount of memory a single suphp process can use? (Basically, something like the setting in php.ini which limits suphp processes in the same way.)
I am using Slackware 12.2 on my laptop compaq presario V2356AP Intel centrino 1.6ghz 1 GB Ram and Slackware is installed on 16gb partition with 10 gb free now.When i installed it was fine over a few days slackware is giving me high response time. while playing videos it is getting stuck firefox is giving bad responses and even konqueror.I heard that slackware is one of the fastest linux and is old hardware friendly right
My problem seems to be very simple, it's high memory usage. I occasionally will use movie player to watch a few shows and I use firefox as well. My memory usage starts out real small about 500 mb but after using firefox lightly and movie player it jumps to almost 2 gigs and this is after they've been closed what gives? I've attached an image so you can see what I'm talking about.
Most of my many Linux installs boot up to a memory use of 170-190 MB with no open or running programs. But with Ubuntu 9.10 it shows; 305-310 MB and the top RAM use item is the; compiz.real, which I think is a display desktop effects application. I have the nvidia video card driver installed, and that nvidia X-Server configuration tool. Also I can not find where that compiz options is at, ( the display options in system, preferances does not open, and says to use my video card tool ).
I have a kernel module that I am trying to do a phys_to_virt() and then perform a memcpy to the returned virtual address. The problem that I'm having is that my module crashes during the memcpy when trying to do this on a physical address in high memory. Do I need to need to perform some kind a mapping operation on high memory address for this to work?
I've installed my debian sid about one month ago (first xfce, next gnome) but noticed that it's kind of really slow. The upgrades take ages, launching (and using) firefox takes so much time,... In comparaison to my ubuntu, archlinux (on the same computer) or previous installation of debian there is clearly a problem somewhere.Today I tried to do a "top" sorted by mem usage : 3.5% xulrunner-stub, 2.1% dropbox, 1.4% aptitude (doing upgrade), 1.4% clementine,... nothing terriblebut still I've 2.7Gb or RAM used (more than 50%)
$ free -m total used free shared buffers cached Mem: 3967 26851282 0 79 1938
I have a server running samba process and there are about 70 samba users connected at a time. The system has 4Gb of memory and it seems each samba process is utilizing only 3352Kb of memory. When I run the command pmap -d (pid of samba)
But when I run the top command, it results as below: Tasks: 163 total, 1 running, 162 sleeping, 0 stopped, 0 zombie Cpu(s): 0.9% us, 4.9% sy, 0.0% ni, 93.3% id, 0.8% wa, 0.2% hi, 0.0% si Mem: 3895444k total, 3163192k used, 732252k free, 352344k buffers Swap: 2097144k total, 208k used, 2096936k free, 2487636k cached
Why could the system be utilizing such high memory? By the way, the server is not running other processes. The samba version running in it is 3.0.33-0.17.
I've written a program for a class that my professor will be testing in various low memory environments to see how it behaves when the program runs out of memory. Is there a way I can simulate the execution in a low memory environment without creating a virtual machine?
I have a 32 bit Ubuntu installed and my Laptop has 4GB RAM, but only 3GB is considered by Linux. My question is: what is the reason for the upper limit on physical memory ?
Code: dmesg | grep Memory [0.000000] Memory: 3052428k/3112960k available (4673k kernel code, 56364k reserved, 2121k data, 656k init, 2200904k highmem) I am familiar with the virtual memory concept where linux splits upper 1GB for kernel and lower 3GB for user processes. In total, linux 32bit can address 4GB virtual addresses. Does this meant that 1GB of physical memory is already mapped to 1GB of kernel space and Linux only shows the remaining 3GB physical memory left for the user in the above command.
I did some searching on the internet and found some articles related to this, but it only confused me further since some articles suggest 4GB is the upper limit with mentioning whether it's virtual or physical memory, some bring in the concept of PAE, etc. I'm relative new to Linux's memory management, so it'd be really helpful if someone could answer this.
When I run ardour sound editing I get this message , but it starts ok Your system has a limit for maximum amount of locked memory! This might cause Ardour to run out of memory before your system runs out of memory. You can view the memory limit with 'ulimit -l', and it is normally controlled by /etc/security/limits.conf
bash-4.1$ ulimit -l 64 my limits.conf is like this audio - rtprio 99 @audio - memlock 250000
I was looking into using control groups to limit the memory usage of each user on my CentOS system. I was told that this required me to recompile the kernel to have cgroup support. Is this true? Or is there a kernel module that will allow cgroups to work for users and groups on the system without kernel re-compile? Or, is there another way to limit the users memory usage? I have tried ulimit and it doesn't seem to work right.
I ask since this setup will be on a VPS system, that means to re-compile the kernel I need to use Xen instead of OpenVZ. Plus I have never in my life re-compiled the kernel, least of all with different modules ha ha ha so I would have to pay my NOC to do it. So if I don't HAVE to recompile the kernel to get cgroup support.
I upgraded from Fedora 13 to 14 over the network. Everything seems to have worked. The one problem after my install is that I have noticed that setroubleshootd consumes alot of memory.
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It doesn't take long for setroubleshootd to jump in memory usage. I can kill the process but it will start up again. I have tried disabling the service but it doesn't show up in /etc/init.d. # service setroubledshootd stop setroubledshootd: unrecognized service So I am not sure what I can do to resolve the issue with setroubleshootd besides killing it off every 15 minutes.
In our database, when checking the memory used using top command, we are always seeing 32 GB RAM utilized. We have set the sga_max_size to 8gb and PGA to 3 gb. We have tried shutting down oracle db and then the memory went down to 24GB when checked using top command. After cold reboot of the DB server, it gone down to 1.5 GB.
But once the users are started using after end of day, the memory again gone back to 32 GB.
Basically I have a machine with 16GB of RAM and have just discovered that using all of it can crash the whole system over one process. How could I run a process on the system in such a way that if more than 90% of system memory is used, the process immediately crashes?
I presently have Fedora 12 running on a Dell Optiplex with a Pentium 4 CPU. I want to buy a new computer, probably from Dell, I don't completely understand the options I have available for which Fedora 13 will run.I more or less understand what 64 bit means since I also have an HP with an AMD 64 bit processor. But are there other options which will allow me to exceed the i386 memory limit? How about dual processors?
I used to understand CPU architecture pretty well, but i've lost track of more recent developments. Can anyone recommend a primer of CPU types, including assoicated memory limits? Similarly, I would like to be sure that Fedora 13 will run on whatever machine I decide to get. So a list of available processors, which are equivalent to which, and which Fedora 13 has been tested on,
i am having a problem that i would call a bit "important" with my server. so, from last 3 weeks the used space of my hard disk (RAID I) started growing up. i have 2 x 1 tb HDD working on RAID I and i did not install anything those weeks. the space just started changing from 90 GB till 580 GB. now the situation is stable there but i think it's not normal.
the bandwidth usage is low (like 120 gb in 2 months) and i am running 6 counter strike gameservers, a forum, a very little website and some local stuffs... a friend of mine told me that my server could have been hacked but i am afraid it did... some useful informations: when i reboot the server the used space goes down again to ~100 GB and then it starts going up again. i cant really find where all those files are located:
I recently upgraded to Ubuntu 10.10 and I am experiencing an ultra high memory usage of the gnome-settings-daemon of 2GB after suspend! Killing and restarting the daemon solves the issue. Anybody else with this behavior?
I'm having a problem with setrlimit() under linux.
If i used setrlimit(RLIMIT_AS) to set a hard ceiling of virtual memory usage first, then request memory more than that, shouldn't i receive a signal like SIGSEGV?
First i tried the command ulimit in bash, which acted as if i called setrlimit(). i tried 3 programs that overflowed the memory limit i set. i though all the programs would be terminated by a SIGSEGV. but the pascal program received SIGKILL; the C++ program got SIGABRT› the C program, SIGSEGV.
I though there maybe something different between setrlimit() and ulimit, so i wrote a program in C++, fork() first, setrlimit() then execv() in the child, and wait(&status) in the parent. but i got the same result.
I was wondering why these could happen, and could anyone tell me how could i deal with them? i mean, how can i judge that the program exited abnormally because it exceed memory limit?
I am having a php script which is used for bulk mailing. I run the script every minute through cron job. I have mentioned the path of the php script in a .sh file and execute the .sh file through cron job. Every time i run the script it utilizes high memory which results to server crash. how to restrict memory usage for that process to be a minimum one or how to set priority to be low for that process so that it is executed when there is no high priority jobs, so that the server runs normally without going down when the script runs
I was browsing my folder with lots of images, after finished i close nautilus and i notice that my computer became slow, so i'll check it with system monitor and had found that nautilus are using almost 100mb of ram (opening 4 tabs). I'm not sure if this was normal or not because i try to reopen the same folder with pcmanfm and it only consumes less than 20mb of ram (opening 4 tabs). here's the screenshot from system monitor .
I have a pretty fresh install on Ubuntu 10.10 Server, with the LAMP bundle installed. Anyway, I just restarted the computer after changing the /etc/network/interfaces script to connect via dhcp. Now when I boot into the server, there is no command prompt and seems to hang there forever, with one blinking cursor in the top left hand corner of the screen. It will not respond to any input besides ctrl-alt-delete. I was able to press control-alt-delete and the computer automatically restarted itself, but it returns to the same state after each reboot. I booted from the grub menu into recovery mode and made sure the /etc/network/interfaces script was correct, and it is. Also I don't think an error in this file should cause the computer to not boot into the command prompt.
I have a few multi-user servers in an academic laboratory. I am having a problem with some users maxing out the available RAM, causing such sever slowdowns the machine essentially crashes. My servers are Dell Power Edge's running Ubuntu 8.10 Server Edition (Not my choice). I would like to set a maximum limit on the amount of ram a user can utilize. This morning I experimented with setting limits via /etc/security/limits.conf and using ulimit. Neither of them prevented my test program, a simple infinite loop of mallocs, from crashing the server.
In the 11.4 product highlights it says: "...availability of PulseAudio in a Plasma Desktop session by default", but what does this mean to the average KDE user? The SUSE-Wiki has no entry for pulse nor pulseaudio.
While basic sound works fine out of the box for me, I am confused between Phonon, KMix and PulseAudio. Each does something else:KMix is now entirely useless, right? Phonon only allows me to select which sound device is used for which input. PulseAudio allows me to select indivdual volume per Application through pavucontrol, but it does not replace phonon nor Kmix There is no KDE Plasmoid/Systray thingy for configuring volume with PulseAudio? Is there no single application/plasmoid to handle all sound options in one go?
I think it is pretty bad that pavucontrol is not even installed for KDE-users by default, and it took me a while to figure it out. Or is there another application that a KDE-user should rather use by default?
I mean things work fine, such as using Phonon to automatically choose my Bluetooth headset for voice communication while music and games at the same time automatically use the speakers for output. Changing volume with pavucontrol works, but why do I need separate things for that?
This is not meant as a rant! I am just wondering whether the PulseAudio/KDE-Integration is just work-in-progress, or whether I am missing something important here entirely. After all, 11.4 and KDE 4.6 looks pretty polished to me overall, and so the audio situation sticks out as odd to me.
There's a proprietary application that I need that is packaged within a Ubuntu 9.04 live ISO, so I'd like to upgrade the whole thing, including the kernel + libraries to benefit from its extra hardware support, add some missing applications and device drivers, and generate a new ISO ready to be burned on a USB/CD.
What issues should I expect? Are Linux applications/libraries downward-compatible, so that the proprietary application is likely to still work, even though I upgraded the kernel and libraries?
I'm trying to delete files that are useless and large since I'm running out of diskspace. Some of the files are (I think) Vi session files that are stored in /var/tmp dir, they are named elvis1.ses, elvis2.ses, etc.
I have a server with 48 cores, 8 6-way Opteron CPU's. Ubuntu Server 9.04 only sees 32 processors. Is there a limit on the number of cores/processors that the server will use? Windows 2008 on the same server sees all 48 cores and the so does the BIOS, so this is unique to Ubuntu right now.
I really don't understand what's happening.I make a 3.5tb RAID array in Disk Utility, yet it makes it so that one partition is 3tb and the other is 500 gigs free!Why is that? Ext4 can do huge partition sizes I thought.
