UNIX for Dummies Questions & Answers

I am running RH 7.1 and i am always remotely logged in working on a database. I got php and mysql running and then as the each week goes my rsh, or secure telnet, and any other remote session slows to become extremly choppy. If i am at teh box my i am fine the computer is not bogged down at all, my webpages still load just as fast, but my lose my remote connection. It took 3 minutes just to type in shutdown -r now, but now it is fine.

You may have a process running with a memory leak. So, you need to isolate the leak by finding a way to take periodic snapshots of the process table and write them to a file with a time stamp. Then, when you reboot the machine, you can log in and find the offending process.

ps with right right switches, exeuted from the crontab, and output redirected properly, will do the trick.

On the other hand, you can just login when the system has been running for a while and manually check your processes. You may easily find it that way if you can get in, remotely.

How do I know what is a memory leak?? Is that just where more and more processes open or dont get shut down? How many httpd, and mysql process should be running if i am not even connected to teh servers?

And does this have any thing to do with possible errors. I seem to get this about once a day.

Date: Fri, 14 Sep 2001 04:03:12 -0700
From: Cron Daemon <root@zoe>
To: root@zoe
Subject: Cron <root@zoe> run-parts /etc/cron.daily

/etc/cron.daily/tripwire-check:

**** Error: Tripwire database for zoe not found. ****
**** Run /etc/tripwire/twinstall.sh and/or tripwire --init. ****

Processes that have memory leaks will be using lots of memory and not releasing the memory to other processes. This often occurs when a process allocates memory (sometimes in a branch of the process that is done repeatedly) and the allocation is not released.

If you have your system set up for swap; then you will notice that your system begins to swap, slowing things down. If you don't have enough swap space (or any swap) things will grind to a halt.

Too many processes can also slow things down, but this is not a memory leaks, just too little memory!!!

How much RAM do you have? How much swap space? What are the top memory-hog-processes on your system?

I have 512 in ram and 200 in swap space. And this is my results as off ps -A. This is with few to no one connected to my computer.
PID TTY TIME CMD
1 ? 00:00:04 init
2 ? 00:00:00 keventd
3 ? 00:00:00 kapm-idled
4 ? 00:00:00 kswapd
5 ? 00:00:00 kreclaimd
6 ? 00:00:00 bdflush
7 ? 00:00:00 kupdated
8 ? 00:00:00 mdrecoveryd
447 ? 00:00:00 pump
514 ? 00:00:00 syslogd
519 ? 00:00:00 klogd
533 ? 00:00:00 portmap
548 ? 00:00:00 rpc.statd
632 ? 00:00:00 apmd
681 ? 00:00:00 automount
693 ? 00:00:00 atd
708 ? 00:00:00 sshd
728 ? 00:00:00 xinetd
788 ? 00:00:00 gpm
795 ? 00:00:00 mysqld
810 ? 00:00:00 mysqld
811 ? 00:00:00 mysqld
812 ? 00:00:00 mysqld
813 ? 00:00:00 httpd
825 ? 00:00:00 crond
826 ? 00:00:00 httpd
827 ? 00:00:00 httpd
828 ? 00:00:00 httpd
830 ? 00:00:00 httpd
831 ? 00:00:00 httpd
832 ? 00:00:00 httpd
833 ? 00:00:00 httpd
905 ? 00:00:00 xfs
950 tty1 00:00:00 mingetty
951 tty2 00:00:00 mingetty
952 tty3 00:00:00 mingetty
953 tty4 00:00:00 mingetty
954 tty5 00:00:00 mingetty
955 tty6 00:00:00 mingetty
956 ? 00:00:00 gdm
963 ? 00:00:03 X
964 ? 00:00:00 gdm
975 ? 00:00:00 gdmlogin
1312 ? 00:00:00 mysqld
1313 ? 00:00:00 mysqld
1479 ? 00:00:00 mysqld
1560 ? 00:00:00 mysqld
1562 ? 00:00:00 mysqld
1725 ? 00:00:00 httpd
1731 ? 00:00:00 mysqld
1732 ? 00:00:00 mysqld
1772 ? 00:00:00 in.telnetd
1773 pts/0 00:00:00 login
1774 pts/0 00:00:00 bash
1810 pts/0 00:00:00 su
1811 pts/0 00:00:00 bash
1850 ? 00:00:00 crond
1851 ? 00:00:00 run-parts
1861 ? 00:00:00 awk
1862 ? 00:00:00 sa1
1864 ? 00:00:00 sadc
1865 pts/0 00:00:00 ps

ps -A does not show the correcg memory usage stats. Please check the man page for ps for the right switches.