Linux Job Management Notes - Revision history

BenFranske: moved User talk:Shari to Linux Job Management Notes

2011-07-18T19:43:37Z

moved User talk:Shari to Linux Job Management Notes

← Older revision	Revision as of 19:43, 18 July 2011
(No difference)

Shari at 01:49, 18 July 2011

2011-07-18T01:49:25Z

← Older revision		Revision as of 01:49, 18 July 2011
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	CFDisk is a tool that is used to partition a hard disk it is a Linux partition editor, similar to fdisk, but with a different user interface.		CFDisk is a tool that is used to partition a hard disk it is a Linux partition editor, similar to fdisk, but with a different user interface.

	The mkfs command makes a new file system on a specified device the ~~mkfs~~ command initializes the file system ~~label and startup block~~.		The mkfs command makes a new file system on a specified device the command initializes the file system.

	The mount command serves to attach the file system found on some device		The mount command serves to attach the file system found on some device.

Shari at 01:46, 18 July 2011

2011-07-18T01:46:47Z

← Older revision		Revision as of 01:46, 18 July 2011
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	1. dmesg \| less to find information about the hard drive on your system		1. dmesg \| less to find information about the hard drive on your system

	2. sudo ~~cfdick~~ /dev/sda or your disk name could be sdb to find and partition the hard drive		2. sudo cfdisk /dev/sda or your disk name could be sdb to find and partition the hard drive

	3. while inside cfdick you can follow the prompts to create new partitions when finished tab to write and then exit cfdisk, you are returned to the command line		3. while inside cfdick you can follow the prompts to create new partitions when finished tab to write and then exit cfdisk, you are returned to the command line
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	7. you can then use the df -1 command to check the free space on each partition		7. you can then use the df -1 command to check the free space on each partition

			CFDisk is a tool that is used to partition a hard disk it is a Linux partition editor, similar to fdisk, but with a different user interface.

			The mkfs command makes a new file system on a specified device the mkfs command initializes the file system label and startup block.

			The mount command serves to attach the file system found on some device

Shari at 16:18, 14 July 2011

2011-07-14T16:18:46Z

← Older revision		Revision as of 16:18, 14 July 2011
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	4. sudo mkfs –t name of file system /dev/sdb number of partition could be 1 through 4 this step must be done for each partition		4. sudo mkfs –t name of file system /dev/sdb number of partition could be 1 through 4 this step must be done for each partition

	5. create the mount points ~~or empty~~ directories using the mkdir name of directory this is where you are going to mount the partitions		5. create the mount points new directories using the mkdir name of directory command this is where you are going to mount the partitions

	6. sudo mount /dev/sda# (or name and number of disk) name of directory you are mounting to		6. sudo mount /dev/sda# (or name and number of disk) name of directory you are mounting to

	7. you can then use the df -1 command to check the free space on each partition		7. you can then use the df -1 command to check the free space on each partition

Shari at 16:17, 14 July 2011

2011-07-14T16:17:33Z

← Older revision		Revision as of 16:17, 14 July 2011
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	'''''Partitions'''''		'''''Partitions'''''

	Partitioning the hard disk helps to separate data from other data on your hard disk by breaking the hard disk into chunks. Without any partitions, your hard disk is one chunk of empty space where no file system can be stored. There are good reasons to make more than one partition on a hard drive. With multiple partitions, you can easily collect similar data sets into one partition, which keeps everything logically and physically separate. The hard disk for SCSI disks is labeled device/sata drives /dev/sda, /dev/sdb, and so on. SCSI hard drive partitions is represented by an additional number first drive first partition, /dev/sda1, second partition, /dev/sda2 and so on. The ~~steps~~ for partitioning a hard drive are:		Partitioning the hard disk helps to separate data from other data on your hard disk by breaking the hard disk into chunks. Without any partitions, your hard disk is one chunk of empty space where no file system can be stored. There are good reasons to make more than one partition on a hard drive. With multiple partitions, you can easily collect similar data sets into one partition, which keeps everything logically and physically separate. The hard disk for SCSI disks is labeled device/sata drives /dev/sda, /dev/sdb, and so on. SCSI hard drive partitions is represented by an additional number first drive first partition, /dev/sda1, second partition, /dev/sda2 and so on. The commands for partitioning a hard drive are:

	1. dmesg \| less to find information about the ~~second~~ hard drive ~~you just added /dev/sdb~~		1. dmesg \| less to find information about the hard drive on your system

	2. sudo cfdick /dev/sdb to find and partition the hard drive		2. sudo cfdick /dev/sda or your disk name could be sdb to find and partition the hard drive

	3. while inside cfdick you can follow the prompts to create new partitions when finished tab to write and then exit cfdisk you are returned to the command line		3. while inside cfdick you can follow the prompts to create new partitions when finished tab to write and then exit cfdisk, you are returned to the command line

	4. sudo mkfs –t name of file system /dev/sdb number of partition		4. sudo mkfs –t name of file system /dev/sdb number of partition could be 1 through 4 this step must be done for each partition

	5. create the mount points or empty directories using the mkdir		5. create the mount points or empty directories using the mkdir name of directory this is where you are going to mount the partitions

	6. sudo mount /dev/~~sdb~~# name of directory you are mounting to		6. sudo mount /dev/sda# (or name and number of disk) name of directory you are mounting to

	7. you can then use the df -1 command to check the free space on each partition		7. you can then use the df -1 command to check the free space on each partition

Shari at 16:01, 14 July 2011

2011-07-14T16:01:16Z

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	The first block read is the superblock that provides information on the disk shape, free space, and location of the first i-node. The superblock is redundant and placed after every group that contains an i-node and data.		The first block read is the superblock that provides information on the disk shape, free space, and location of the first i-node. The superblock is redundant and placed after every group that contains an i-node and data.
	The i-node is a control structure every directory gets an i-node that includes information about the files owner, permission, size, and group id, but not the file name. The i-node then points to the files in that directory.		The i-node is a control structure every directory gets an i-node that includes information about the files owner, permission, size, and group id, but not the file name. The i-node then points to the files in that directory.


			'''''Partitions'''''

			Partitioning the hard disk helps to separate data from other data on your hard disk by breaking the hard disk into chunks. Without any partitions, your hard disk is one chunk of empty space where no file system can be stored. There are good reasons to make more than one partition on a hard drive. With multiple partitions, you can easily collect similar data sets into one partition, which keeps everything logically and physically separate. The hard disk for SCSI disks is labeled device/sata drives /dev/sda, /dev/sdb, and so on. SCSI hard drive partitions is represented by an additional number first drive first partition, /dev/sda1, second partition, /dev/sda2 and so on. The steps for partitioning a hard drive are:

			1. dmesg \| less to find information about the second hard drive you just added /dev/sdb

			2. sudo cfdick /dev/sdb to find and partition the hard drive

			3. while inside cfdick you can follow the prompts to create new partitions when finished tab to write and then exit cfdisk you are returned to the command line

			4. sudo mkfs –t name of file system /dev/sdb number of partition

			5. create the mount points or empty directories using the mkdir

			6. sudo mount /dev/sdb# name of directory you are mounting to

			7. you can then use the df -1 command to check the free space on each partition

Shari at 15:57, 14 July 2011

2011-07-14T15:57:05Z

← Older revision		Revision as of 15:57, 14 July 2011
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	''step'' 4 you will have to change network configuration file and run fsck		''step'' 4 you will have to change network configuration file and run fsck


			'''''Stopping'''''

			Here are some basic shutdown commands to cleanly shutting down your system you have to be root or use the sudo command

			Shutdown –h now= shutdown the system now and do not reboot

			shutdown –r now= shutdown the system now and reboot


			'''''File system ext2, ext3, superblocks, i-nodes'''''

			A file system organizes data on the storage medium in layers on the disk, ext2 file system has the concept of blocks, i-nodes and directories, ext3 is ext2 file system improved with journaling capabilities, journaling allows fast file system recovery and is the default file systems for Linux.
			The first block read is the superblock that provides information on the disk shape, free space, and location of the first i-node. The superblock is redundant and placed after every group that contains an i-node and data.
			The i-node is a control structure every directory gets an i-node that includes information about the files owner, permission, size, and group id, but not the file name. The i-node then points to the files in that directory.

Shari at 15:50, 14 July 2011

2011-07-14T15:50:20Z

← Older revision		Revision as of 15:50, 14 July 2011
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	If something goes wrong with the startup scripts that affects the boot process it is possible to boot into single user mode, make any repairs needed, and then boot into multiuser mode this process involves four steps.		If something goes wrong with the startup scripts that affects the boot process it is possible to boot into single user mode, make any repairs needed, and then boot into multiuser mode this process involves four steps.

	step 1 At the grub boot screen (after restart), select the kernel, press the e key to edit the entry, and the select second line (the line starting with the word kernel)		''step'' 1 At the grub boot screen (after restart), select the kernel, press the e key to edit the entry, and the select second line (the line starting with the word kernel)

	step 2 select kernel entry, press e again, add key word single to the end of line, press enter, press B to boot into single user mode		''step'' 2 select kernel entry, press e again, add key word single to the end of line, press enter, press B to boot into single user mode

	step 3 the init file will only go through runlevel 1, type root password press enter		''step'' 3 the init file will only go through runlevel 1, type root password press enter

	step 4 you will have to change network configuration file and run fsck		''step'' 4 you will have to change network configuration file and run fsck

Shari at 15:48, 14 July 2011

2011-07-14T15:48:56Z

← Older revision		Revision as of 15:48, 14 July 2011
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	The job of making sure the systems hard disk is in a reliable state is shared by the runlevel scripts and a file called /etc/fstab file. The fsck stands for file system check program is used to check and repair the file system it automatically runs during the boot process. If the system shuts down without any problems the autofsck file is deleted, and fsck will run without any problems. But if the system is shut down hard fsck will run thought all of the local disk listed in the /etc/fstab file to check for a problem, if there is a problem fsck will ask you if you want to fix it.		The job of making sure the systems hard disk is in a reliable state is shared by the runlevel scripts and a file called /etc/fstab file. The fsck stands for file system check program is used to check and repair the file system it automatically runs during the boot process. If the system shuts down without any problems the autofsck file is deleted, and fsck will run without any problems. But if the system is shut down hard fsck will run thought all of the local disk listed in the /etc/fstab file to check for a problem, if there is a problem fsck will ask you if you want to fix it.


			'''''Single user mode'''''

			If something goes wrong with the startup scripts that affects the boot process it is possible to boot into single user mode, make any repairs needed, and then boot into multiuser mode this process involves four steps.

			step 1 At the grub boot screen (after restart), select the kernel, press the e key to edit the entry, and the select second line (the line starting with the word kernel)

			step 2 select kernel entry, press e again, add key word single to the end of line, press enter, press B to boot into single user mode

			step 3 the init file will only go through runlevel 1, type root password press enter

			step 4 you will have to change network configuration file and run fsck

Shari at 05:38, 14 July 2011

2011-07-14T05:38:02Z

← Older revision		Revision as of 05:38, 14 July 2011
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	The job of making sure the systems hard disk is in a reliable state is shared by the runlevel scripts and a file called /etc/fstab file. The fsck stands for file system check program is used to check and repair the file system it automatically runs during the boot process. If the system shuts down without any problems the autofsck file is deleted, and fsck will run without any problems. But if the system is shut down hard fsck will run thought all of the local disk listed in the /etc/fstab file to check for a problem, if there is a problem fsck will ask you if you want to fix it.		The job of making sure the systems hard disk is in a reliable state is shared by the runlevel scripts and a file called /etc/fstab file. The fsck stands for file system check program is used to check and repair the file system it automatically runs during the boot process. If the system shuts down without any problems the autofsck file is deleted, and fsck will run without any problems. But if the system is shut down hard fsck will run thought all of the local disk listed in the /etc/fstab file to check for a problem, if there is a problem fsck will ask you if you want to fix it.

	~~Processes: ps, top, kill signal~~

	~~The ps command stands for process status it list all the processes in a system, if they are running, stopped, or in a zombie state. The most common parameter is ps auxww~~

	~~Example: at the command line type ps auxww press Enter~~

	It you want to look at the processes that are running on your system line by line you can use \| less like this. Example: at the command line type ps auxww \| less Enter you can then use the down arrow to scroll line by line.

	The top command shows what is running on your system in real time it refreshes every two to three seconds. Top is an interactive program with a command line within the program that can be used to prioritize or kill processes. To start the top program use the following command.

	~~Example: at the command line type top press Enter~~

	~~Top is a CPU hog if several people are using the program. To prevent other users from running this program you can change the permissions so only root users are allowed access.~~

	~~Example: at the command line type chmod 0700 `which top`~~

	~~To exit top type q for quit and you are back to the command line.~~

	The kill command is misleading in that it is not guaranteed to stop a process, but it does send a signal to the running process. The operating system by default supplies each process with signal handlers to deal with incoming signal differently. To send the kill signal you need at least one parameter, and the process identification number from the ps command list.

	~~The most common handlers are:~~

	~~ 9 the operating system simply kills the process,~~

	~~ 15 the SIGTERM signal you must clearly specify -15 or TERM to terminate~~

	~~ 1 to hang up also called SIGHUP OR HUP this signal gives the process time to perform a clean shutdown~~

	~~Example: at the command line type kill –signal handler# PID# from ps command list~~

	~~Remember that root users can kill any process, but standard users can only kill the processes they have permission to kill.~~