Red Hat Enterprise Linux 5 Administration Unleashed

556APPENDIX DTroubleshootingQ. I need to start a graphical program from a remote server. I used the SSH utility to loginto it. But, when I run the command to start the graphical program, I see thefollowing error:Unable to initialize graphical environment. Most likely cause of failureis that the tool was not run using a graphical environment. Please eitherstart your graphical user interface or set your DISPLAY variable.Caught exception: could not open displayA. You need to enable X11 forwarding to be able to display a graphical interface on aremote system via SSH. Use the -Y option when executing the ssh command toconnect to the server:ssh -Y Monitoring and Tuning TroubleshootingQ. How do I limit the amount of memory each user is allowed to use so one user can’thog all the memory and slow down the other users?A. The /etc/security/limits.conf file allows an administrator to limit the amount ofmemory locked in by an individual user or a user group. The file must be edited bythe root user. Each line in the file contains four values: The value is a valid username or a group name preceded by the @ symbolsuch as @legal. The type must be either soft for enforcing as a soft limit or hard forenforcing as a hard limit. The item should be memlock for limiting locked inmemory. The value is the value of the limit, which is an integer that represents themaximum amount of memory in kilobytes.TIPRead the comments in /etc/security/limits.conf and the limits.conf man pagefor details on how to limit other items such as maximum filesize allowed by a user andmaximum number of users allowed to log into the system at the same time.Q. The processors in my four-way server were being maxed out, so I installed two moreprocessors. How do I tell whether Linux recognizes the new processors?A. The kernel should automatically detect the new processors and balance the loadbetween all processors. To verify the processors are recognized, use the cat/proc/cpuinfo command to view a list of all processors found by the kernel. Youshould see a processor stanza for each processor. If you have multi-core processors,each processor core is listed as a separate processor. Refer to Chapter 8, “64-Bit,Multi-Core, and Hyper-Threading Technology Processors” for details on reading theoutput for multi-core processors.