Re: [Hampshire] Troubleshooting Memory Leak
Hey Stephen, Not sure if this applies to Linux operating systems or not but I had something similar happening under XP at work. Turns out a call was being made to the OS which was then malloc'ing some memory that the application was meant to free when it was finished with it. The memory allocated was not listed against the application though (as the OS had done the malloc) so it was a bit tough to track down. Just something else to look out for, HTH. Stu 2009/3/24 Stephen Nelson-Smith > I have a CentOS 5 server running nginx, httpd and a dozen or so > mongrel instances. Since this morning I've been experiencing a > serious memory leak - about 2G in 2 hours, until the machine needs to > be rebooted. I've tried to answer the question "what changed", and I > can't think of anything on my side... > > In top, and related tools, I see no processes growing in size - all I > see is the amount of memory available constantly reducing. > > The sort of thing I can think of that fits the evidence would be > something like a process is being created and then dying without > returning the memory to the system. > > However, I am unable to see the malloc's, and I can't currently think > of a way to test this theory. > > I suspect systemtap may be the tool to use - anyone have experience of > using it in this way, or have a recipe they could point me to? > > Any other ideas for troubleshooting and gathering info? > > Thanks in advance, > > S. > > -- > Stephen Nelson-Smith > Technical Director > Atalanta Systems Ltd > www.atalanta-systems.com > > -- > Please post to: Hampshire@mailman.lug.org.uk > Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire > LUG URL: http://www.hantslug.org.uk > -- > -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
[Hampshire] Troubleshooting Memory Leak
I have a CentOS 5 server running nginx, httpd and a dozen or so mongrel instances. Since this morning I've been experiencing a serious memory leak - about 2G in 2 hours, until the machine needs to be rebooted. I've tried to answer the question "what changed", and I can't think of anything on my side... In top, and related tools, I see no processes growing in size - all I see is the amount of memory available constantly reducing. The sort of thing I can think of that fits the evidence would be something like a process is being created and then dying without returning the memory to the system. However, I am unable to see the malloc's, and I can't currently think of a way to test this theory. I suspect systemtap may be the tool to use - anyone have experience of using it in this way, or have a recipe they could point me to? Any other ideas for troubleshooting and gathering info? Thanks in advance, S. -- Stephen Nelson-Smith Technical Director Atalanta Systems Ltd www.atalanta-systems.com -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
Re: [Hampshire] insmod problem
> testerm...@marvin:/dev$ xawtv > This is xawtv-3.95.dfsg.1, running on Linux/i686 (2.6.18-4-486) > can't open /dev/video0: No such file or directory > v4l-conf had some trouble, trying to continue anyway > v4l2: open /dev/video0: No such file or directory > v4l2: open /dev/video0: No such file or directory > v4l: open /dev/video0: No such file or directory > no video grabber device available > testerm...@marvin:/dev$ > > should I move video0 to /dev. tried to copy it and was unable to. > > Cheers > Mike > > OK put the TV card back in but the modules for the usb cam are still not loading. So have been trying to re-install qc-usb. I am booting from the 2.6.18-4-48 kernel. The configuration shell script is failing because it can't find the headers or source files. I have installed the headers but have drawn a blank on the etch source files. Do I need the source files really ? (it would seem so) and What is the correct package please? I couldn't seem to find an appropriate one on debian.org and the mirrors in my sources list returned a 404 error. TIA Mike -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
Re: [Hampshire] Server Security
Roger Munford wrote: > Thanks for all your advice. There is a lot to work through but I am > grateful for the practical advice. > > One of the joys? of working with computers is getting something working > and seeing a benefit. Sometimes you can achieve something with only a > vague idea of what you are doing. Unfortunately these days you have to > be on top of the game and there seem to be so many vulnerabilities to > know about. > It is a joy, the most rewarding moments often come after a long period of joy drought, the fun police are out and it's a shame. Stick with it Roger, you are asking the right questions. Cheers Damian -- http://www.diap.org.uk - distributed archive storage system under development. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
[Hampshire] Server Security
Thanks for all your advice. There is a lot to work through but I am grateful for the practical advice. One of the joys? of working with computers is getting something working and seeing a benefit. Sometimes you can achieve something with only a vague idea of what you are doing. Unfortunately these days you have to be on top of the game and there seem to be so many vulnerabilities to know about. Roger -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
Re: [Hampshire] Server Security
One addition to a point of Damian's: 2009/3/20 Damian Brasher : > 10) Be consistent, be creative (but test creative configuration before > production), and finally write documentation as you go, it can be a simple as > you like but will save you lot's of time in the future. Make use of the tools that are available to you. Use a version control system to keep copies of vital files when you change them. Use some kind of note-taking system to capture what you have set up, why, how, when. 'trac' [1] integrates these two by giving you wiki-type functionality and a change control mechanism together with integration with Subversion for source control of your files. 'Elog' [2] is more just a 'logbook' tool but has nice capabilities. [1] http://trac.edgewall.org/ [2] https://midas.psi.ch/elog/ -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --
