Changes

The purpose of this lab is to demonstrate how a Linux system administrator can monitor hard disk space availability, and to manage file system size via the Logical Volume Manager (LVM) application. This lab will also demonstrate how to manually mount (i.e. connect) and unmount (disconnect) partitions to file system directories, and demonstrate how to have partitions automatically mounted to directories upon Linux system startup. <u>Main Objectives<br/u> :* Using '''LVM''' to '''resize partitions graphically and via command-line'''.:* Create, partition and format '''virtual hard disks''' to increase the size of a file system.:* Connecting Manually connect and Disconnecting Directories disconnect directories (mount points) to existing partitions ('''mount''', '''umount''').

:* Using '''LVM''' to '''resize partitions graphically and via commands'''.:* Create, partition and format '''virtual hard disks''' to increase the size of a file system.:* Create a Bash Shell Script script to '''monitor and report low disk size''' (run periodically in '''crontab''').

*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/vgs.8.php html vgs]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/lvspvs.8.php lvshtml pvs]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/pvslvs.8.php pvshtml lvs]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/vgdisplay.8.php html vgdisplay]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/lvdisplaypvdisplay.8.php lvdisplayhtml pvdisplay]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/pvdisplaylvdisplay.8.php pvdisplayhtml lvdisplay]<br>

*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/lvextend.8.php html lvextend]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/lvcreate.8.php html lvcreate]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/lvreduce.8.php html lvreduce]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/pvcreate.8.php html pvcreate]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/vgextend.8.php html vgextend]<br>

*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/mount.8.php html mount]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8/umount.8.php html umount]<br>*[http://linuxmanpagesman7.comorg/linux/man-pages/man8man1/mountdf.81.php html df ]<br>*[http://man7.org/linux/man-hpages/man1/du.1.html du]<br>*[http://linuxmanpageswww.lehman.cuny.comedu/cgi-bin/man-cgi?awk+1 awk]<br>*[http:/man8/mounttldp.8org/HOWTO/Partition/fdisk_partitioning.php html fdisk]<br>*[http://linuxmanpageswww.cyberciti.biz/faq/howto-format-create-linux-filesystem/ mkfs]*[http://man7.org/linux/man-pages/man5/fstab.5.comhtml /etc/fstab]*[http:/man8/mountcode.8tutsplus.php mkfscom/tutorials/scheduling-tasks-with-cron-jobs--net-8800 Using crontab]

=INVESTIGATION 1: Adjusting File System Sizes with MANAGING FILE-SYSTEMS USING LVM={| width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/note|VM Backups and Recovery|Most of these investigations will take place in your virtual machines. If you make a significant mistake, your virtual machine may not boot. Remember that you created backups of your virtual machines in Lab 2, and you can restore them if something goes wrong.<br /><br />'''Remember: if you did not create backups for all of your VMs, then you don't have any restoration points to fall-back to!'''|}}|}Monitoring and ensuring adequate space for a Linux file-system is considered to be a critical task for any system administrator. An application called '''LVM''' is a very useful tool for Linux system administrators to easily manage file systems - even when the computer system is running!

Monitoring and ensuring adequate space for a Linux file-system '''LVM''' ('''Logical Volume Management''') is considered used to be an important task manage hard disk drives / partitions for a sys adminLinux and Unix systems. An application called LVM is provides more flexibility than just partitioning hard disks. '''Volume Groups''' are areas used to define '''Physical Volumes''' (i.e. hard disks, disk partitions, or other forms of storage devices). '''Logical Volumes''' are then used to relate directories (mount points) to a very useful tool specific physical volume or for Linux system adminstratorsa "range" or "span" of physical volumes.

'''LVM''' ('''Logical Volume Management''') is used to manage hard disk drives / partitions for Unix/Linux systems. LVM provides more flexibility than just working with hard disks / hard disk partitions. '''Volume Groups''' are areas used to define '''Physical Volumes''' (i.e. hard disks, disk partitions, or other forms of storage devices). '''Logical Volumes''' are then used to relate directories (mount points) to a specific physical volume or for a "range" or "span" of physical volumes. Therefore, LVM allows more flexibility and growth potential for Linux systems (for example, having Logical volumes span multiple hard disks). CentOS uses LVM by default upon installation. Other Linux distributions may provide the capacity to install LVM, or later install and then use Logical Volume Management.

[[Image:Ops235_lab4_1lvm1.png|thumb|500px|right|The '''system-config-lvm''' application allows the Linux system administrator to manage LVMs Graphically. Your LVM information for '''centos2''' VM should be similarly displayed.]]

# Launch your '''centos2''' VM and open a shell terminal.# CentOS provides a tool called '''system-config-lvm''' to graphically administer LVM. Install <br><br>'''NOTE:''' This tool may be replaced by a future graphical LVM management tool and is NOT currently available in the default repositories. We will now perform a "work-around" in order to make the system-config-lvm application by utility work in our system.<br><br># Issue the following command to download the system-config-lvm rpm:<br><b><code><span style="color:#3366CC;font-size:1.2em;">wget https://kojipkgs.fedoraproject.org//packages/system-config-lvm/1.1.18/1.fc19/noarch/system-config-lvm-1.1.18-1.fc19.noarch.rpm</span></code></b><br>(Although it is an rpm file for the Fedora Distribution, it will also work for Centos7).<br><br># Make certain that you are logged in as '''root'''.# Try issuing the command: <b><code><span style="color:#3366CC;font-size:1.2em;">yum install rpm -i ./system-config-lvm-1.1.18-1.fc19.noarch.rpm</span></code></b><br>You should notice an error.# Use the '''yum install''' command to resolve the following dependencies:<ul><li><b><code><span style="color:#3366CC;font-size:1.2em;">yum install gnome-python2-bonobo</span></code></b></li><li><b><code><span style="color:#3366CC;font-size:1.2em;">yum install gnome-python2-gnome</span></code></b></li><li><b><code><span style="color:#3366CC;font-size:1.2em;">yum install usermode-gtk</span></code></b></li></ul><br>

<li value="38">Open a shell as root and run Re-issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">rpm -i ./system-config-lvm-1.1.18-1.fc19.noarch.rpm</span></code></b><br>It should work this time.</li><li>Run the command: <b><code><span style="color:#3366CC;font-size:1.2em;">system-config-lvm</span></code></b></li><li>On the left-hand side, you can click on the '''Volume Group''', '''Physical Volume ''' and '''Logical Volumes ''' and view their properties on the on the right-hand side.</li><li>Determine the current LVM configuration by clicking on the appropriate element and reading the properties in the right-hand panel -- write down the answers:

<li>What is the name and size of the '''Physical Volumes'''?s</li> <li>What are the names and sizes of the '''Logical Volumes'''s?</li> <li>Is there any space in the VG which is not allocated to a LV?<br><br></li>

<li>Perform the following steps in Click on '''Logical View''' (i.e. above home, root, swap) and then click '''Create New Logical Volume''' button. What happens? Why do you think this application to increase the size of happened?<br><br>We will now create another partition ('''/dev/vda3''') using the '''homefdisk''' fileutility, format this newly-system to created partition so we can create another logical volume called '''4 GBarchive''':.<br><br> </li> <ol type="a"li>Quit the '''system-config-lvm''' application.</li> <li>On In the terminal as root, issue the leftcommand: <b><code><span style="color:#3366CC;font-hand sidesize:1.2em;">ls /dev/vd*</span></code></b><br><br>'''NOTE:''' If nothing displays, click on issue the command: '''Logical Volumels /dev/sd*''' containing the and use that device pathname '''home/dev/sda''' fileinstead.<br><br> <li>Issue the command: <b><code><span style="color:#3366CC;font-systemsize:1.2em;">fdisk /dev/vda</span></code></b><br>(or ''fdisk /dev/sda'' if the previous command didn't work)</li> <li>Click on At the fdisk prompt issue the command: '''Edit Propertiesp'''.What does this do?</li> <li>Change Now issue the commands '''n''' (new partition), '''p''' (primary partition), '''3''' (i.e. next available partition number). When prompted for initial block, '''press enter to accept the default beginning block size to '''4 GB, and '''type: +2G''' at ending block (create 2GB for partition) and click '''Okpress enter'''.</li> <li>Verify that At the fdisk prompt, issue the command '''p''' to review the partition information, then type '''homew''' file-system has increased in sizeto save partition table and exit (ignore WARNING message).</li> <li>You <u>'''must'''</u> restart your centos2 VM to allow changes to take effect</olli> <li>Create Open a terminal as root, and format your newly-created partition by issuing the command: <b><code><span style="color:#3366CC;font-size:1.2em;">mkfs -t ext4 /dev/vda3</span></code></b><br>(or ''mkfs -t ext4 /dev/sda3'new 3G LV')</li></ol>{| width="40%" align="right" cellpadding="10"|- valign="top"|[[Image:lvm3.png|thumb|right|500px|What '' (LV Properties: linear) containing an 'system-config-lvm''ext4'display should appear after using '' filesystem named: 'fdisk''lv_archive'to create new partition (/dev/sda3), '' and mount it at: 'formatting''/archive'partition, '' <li>Let's see what happens when we copy data over adding partition to '''lv_archiveLVM''', and then '''reduce the size of lv_archiveallocating partition'''to our default volume group. Complete the following steps below]]|[[Image:lvm4.png|thumb|right|200px|Creating a new logical volume from our newly created physical volume]]|}<ol> <ol typeli value="21">'''Restart the system-config-lvm utility'''. Do you see a"new /dev/sda3 partition under Physical Volumes?</li> <li>Issue To add the newly created partition, you need to add it into LVM to be used. '''Exit the system-config-lvm utility''' and '''issue the following commandto add the partition into LVM: '''<br><b><code><span style="color:#3366CC;font-size:1.2em;">cp -R pvcreate /etc/* dev/archive vda3</span></code></b> (or ''pvcreate /dev/sda3'' ) (enter '''y''' to proceed - ignore warning)</li> <li>Shrink the size of '''lv_archiveRestart system-config-lvm'''. You should notice a section at the bottom indicating <u>Unallocated</u> Physical Volumes. Click on the <u>unallocated</u> partition /dev/vda3 and then click ''' Add to Existing Volume Group'''1 GB(click on other button in next screen to continue). The screen should now show the partition ''/dev/vda3''contained in our default Volume Group (refer to diagram on right-side for reference). What happens?</li> <li>If you could not shrink Click on Logical View (i.e. above home, root, swap), and then click on '''Create New Logical Volume''' button and fill out the details for this new logical volume including: size of : '''1GB''', LV Properties: '''linear''', file system: '''lv_archiveext4''' file system name: '''archive''', what do you think is select '''mount''' and mount it at: '''/archive'''. Have the system create the cause directory ''/archive'' if it does not exist (Refer to diagram on right for reference).</li> <li>Confirm that this new Logical Volume now exists by changing to the problemdirectory /archive. Did you need to restart your centos2 VM to confirm that the '''/archive''' directory is now on your '''centos2''' VM?</li>  </olli>Use system-config-lvm to resize (i.e. edit) the '''archive''' logical volume to '''1.5 GB''' and verify your results.</li>

===Part 2: Managing LVM Via Command Line=== Let's say that you have run out of disk space on your '''centos3''' VM, you need more space on the root file-system, perhaps to host more webpages or a larger database or new software. What are your options? Getting a replacement hard-drive would probably require re-installation of the operating system and backup/restore of the data. Because we're using LVM we can avoid this problem. We can '''add a new <u>virtual</u> hard-drive''' (which will serve as a physical volume) to the volume group, and extend the root logical volume to make use of the new available space. Creating virtual hard drives is not only inexpensive, but a great way for students to learn now to simulate growing the size of the file system.

<li value="23">Run Record the following commands size of the volume group and make note the amount of the output:free space</li> <codeli>At the top of your VM window (make certain <u>ls /dev/vd* pvs vgs lvs df -hnot</codeu>full screen mode) click the '''view''' menu and change view from '''Console''' to <liu>Open the centos3 virtual machine consoleDetails</liu> <li>Go to the hardware details view''' .</li> <li>Click "At the bottom left-hand corner, click '''Add Hardware" ''' and add a new storage device of '''2GBs''', make sure itthe '''Bus type''' is selected as: '''s a VirtIO disk'''.<br><br>'''NOTE: Make certain to click "select managed or other existing storage", and fill in the pathname circled in red as shown in the diagram on the right-hand-side.<br><br>'''</li> <li>Go back to the '''console ''' view</li> <li>Run Issue the same command: <b><code><span style="color:#3366CC;font-size:1.2em;">ls command /dev/vd*</span></code></b>, what has changed?</li> <li>Use '''fdisk''' (performed ''refer to how to use in step Part 1'') to create a new single primary partition for '''/dev/vdb''' that fills the entire disk, save partition table (accepting defaults prompts would work), whatrestart your '''centos3''' VM and then '''format''' that partition for file type: '''ext4'''s changed?.</li> <li>Now we'll make the new device as a '''physical volume''', add it to the '''volume group''', and extend '''lv_root''':</li> <code>pvcreate /dev/vdb  vgextend vg_centos3 /dev/vdb  lvextend -L +2G -r vg_centos3/lv_root</code> <li>Now rerun the ls/pvs/vgs/lvs/df commands. What has changed and what caused those changes?</li> <li>Among the changes, note that your root filesystem is now 2GB bigger - and you have not even rebooted your machine!</li>

:: <b><code><span style="color:#3366CC;font-size:1.2em;">vgextend ''name_of_volumegroup'Answer Part 2 observations ' /dev/vdb1</span></code></ questions in your lab log book.'''b>

= INVESTIGATION 2: CREATING VIRTUAL HARD DRIVES ADDITIONAL FILE-SYSTEM OPERATIONS =

== Part 1: Mounting and Un-mounting Partitions ==[[Image:mount.png|thumb|700px|right|Using the '''mount''' command with no arguments displays file-systems that are already mounted. The Linux system administrator can use the '''mount''' and '''umount''' commands to connect and disconnect different partitions from the file-system to perform maintenance.]]# xPerform this part in your '''centos2''' VM.# As you may recall in Part 1 of Investigation 1, we created another logical volume called '''archive''' using the graphical application '''system-config-lvm'''. This logical volume should be mounted (connected) to our existing file-system (2GB).# Issue the following command: <b><code><span style="color:#3366CC;font-size:1.2em;">mount</span></code></b># What is the purposed of issuing this command without arguments? Can you see the '''/archive''' mount point?# Confirm that the directory named '''/archive''' is mounted.# You can use the '''umount''' command to unmount a file-system (eg. for maintenance purposes). Note the the name of the command is umount, <u>not</u> unmount.# Make certain you are not located in the /archive directory, and issue the following command to unmount the /archive directory:<br><b><code><span style="color:#3366CC;font-size:1.2em;">umount /archive</span></code></b># Issue the '''mount''' command (without arguments) to confirm it has been unmounted.# View the contents of the file-system table /etc/fstab by issuing the following command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">cat /etc/fstab</span></code></b># Note the line that automatically mounts a file-system (''/dev/sda3'', type ''ext4'') to '''/archive'''. This was automatically performed for you via the '''system-config-lvm''' utility.# View and record the fields for the '''/archive''' mount in your lab logbook, and then issue the following command to reconnect or mount '''/archive''':<br><b><code><span style="color:#3366CC;font-size:1.2em;">mount &nbsp; -t ext4 &nbsp; /dev/centos_centos2/archive &nbsp; /archive</span></code></b><br><br>'''NOTE:''' If you are having problem mounting, use the /dev pathname listing in your /etc/fstab file.<br><br># Confirm that this file-system has been properly mounted. Note: You could have also issued the command: '''mount -a''' to <u>automatically</u> mount the file-systems contained in the '''/etc/fstab''' file.<br><br>Tip: If you had to do manually configure /etc/fstab (eg. only in text-based mode - centos3), you could have issued the command (as root):<br> <b><code><span style="color:#3366CC;font-size:1.2em;">echo "/dev/centos_centos2/archive /archive ext4 defaults 1 2" >> /etc/fstab</span></code></b><br>(although we don't need to do this, since it was already done).<br><br># '''A curious question''': If root needs to unmount the '''/home''' directory for maintenance but we had to first login in graphically as a regular user, then su to "root", isn't our regular user still logged in so we can't un-mount the /home directory?!? How can we as a Linux System Administrator get around the problem (hint: you already learned it somewhere in lab3!!! Wow, using what we already taught can pay-off in the future ... lol!).

We take for granted that a file-system must be mounted (for example the root partition) in order for a Linux system to be usable upon system start-up== Part 2: Monitoring Disk Space ==[[Image:disk_usage. png|thumb|500px|right|The '''/etc/fstabdf''' and '''du''' (file commands are useful tools for Linux system table) contains entries administrators to mount various file systems automatically upon start-up flag disk space issues and investigate their causes.]]Another essential duty of the a Linux systemadministrator is to anticipate problems and take preventative measures to avoid computer system problems <u>before</u> that occur.

The Monitoring disk space activity helps provide Linux sys admin also has the ability to manually '''mount''' (connect) and '''un-mount''' (disconnect) partitions in order to perform maintenance on the file system (for example un-mounting the '''/home''' partition administrators information to install software and prevent users from logging in during that process)help take corrective action before problems can occur.

We will now learn how # Remain in your '''centos2''' VM for this section.# Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">df -h</span></code></b># Note the disk space usage for '''/''', '''/home''', and '''/archive''' partitions.# If a partition is running out of available space, the Linux System Administrator can reallocate space among partitions or add another disk and grow the file system (like you did in a previous investigation). The administrator also can investigate the cause of low disk space. Two examples immediately come to perform these operations (including monitoring mind: excessive use of space from users, and potential penetration from hackers.# To investigate excessive disk usage by regular users, you can obtain a total amount of disk usage for that user by issuing the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">du -hs /home/regularuserid</span></code></b># To provided a more detailed list of usage (file-by-file), issue the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">du -h /home/regularuserid | more</span></code></b># If there is a recurring space usage problem with regular users, the Linux system administrator can impose quotas (caps on disk usage) . This method is not taught in this course.# The methods to monitor potential penetration to a Linux system are too numerous, and are taught in Part other coures (for example: SEC520). On method of monitoring potential penetration is to look for abnormally large files. Issue the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">find -P / -size +100000k</span></code></b># Did you see any files that are that size?# The next section will apply some of these tools we have discussed into a shell script and crontab entry to periodically monitor and contact the system administrator of potential disk space issues (before they become a serious problem).

= INVESTIGATION 43: LOOKING AHEAD =

==Automating Routine Tasks (Scheduling The Running of Shell Scripting and Using Script Via Crontab)==

|{{Admon/tip|Bash Shell Scripting Tips:|<br><ul><li>'''The case statementUsing awk to Manipulate Text:'''<br><br>The case statement is a control-flow statement Legend has it that works in a similar way as the if-elif-else statement (but is more concise). This statement presents scenerios or "cases" based on values or regular expressions (not ranges of values like if-elif-else statements). After action(s) are taken for a particular scenerio (or "case"), a break statement (''';;awk''') is used command was invented by three C programmers that wanted to "break-out" of create a utility in Unix that had programming syntax more like C programming. People started to use the statement (command and found it very useful for report generation and not perform other actions). A default case (*) is also used to catch exceptionsfile repair or manipulation.<br><br><u>The command mimics a C program, with braces '''Examples (try in shell script):{ }'''</u><br><br>''read -p "pick that surround the action to perform based on records from a door (1 or 2): " pick<br>case database file matching either test conditions, regular expressions, etc. Fields appear as numbers with $pick in.<br>&nbsp; 1) echo "You win a car!" ;;<br>&nbsp; 2) echo "You win a bag of dirt!" ;;<br>&nbsp; *) echo "Not a valid entry"<br>&nbsp;&nbsp;&nbsp;&nbsp; exit 1 ;;<br>esac''<br><br>''read -p "enter a single digit: " digit<br>case $digit in<br>&nbsp; [0-9]) echo "Your single digit is: $digit" ;;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; *)&nbsp;echo "not a valid single digit"<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; exit 1 ;;<br>esac''<br><bru>Examples</li><liu>'''The getopts function:'''<br><br></li></ul>The getopts function allows the shell scripter to create scripts that accept options (like options for Linux commands). This provides the Linux administrator with scripts that provide more flexibility and versatility. A built-in function called ''awk 'getopts{print}''' (idata-file.e. get command options) is used in conjunction with a '''while''' loop and a ''txt'case''' statement to carry out actions based on if certain options are present when the shell script is run. The variable '''$OPTARG''' can be used if an option accepts text (denoted in the getopts function with an option letter followed by a colon. Case statement exceptions use the ''':)''' and '''\?)''' cases for error handling.<br><br>''awk -F";" '<u>Example of getopts</u>{print $5,$3}'data-file.txt'' (try in script and run with options)<br><br>''while getopts abc: name<br>do<br>&nbsp; case $name in<br>&nbsp; &nbsp; a) echo awk -F"Action for option \,"a\"" ;;<br>'$4 &nbspgt; &nbsp#61; b) echo "Action for option \"b\"" ;;<br>&nbsp; &nbsp; c) echo "Action for option \"c\""<br>&nbsp; &nbsp; &nbsp; &nbsp; echo Value is: 10000 {print $OPTARG" ;;<br>&nbsp; &nbsp; :) echo "Error: You need text after -c option"<br>&nbsp; &nbsp; &nbsp; &nbsp; exit 1 ;;<br>&nbsp; &nbsp; \?) echo "Error: Incorrect option"<br>&nbsp; &nbsp; &nbsp; &nbsp; exit 1 ;;<br>esac, $2}' salary.txt''<br/li><br/ul>}}

We will now use This emphasis on this section focuses on how to run useful shell scripts or shell scripting script that we have created at specific dates/times. It would be silly to help automate the task for expect a Linux adminstrator system administrator to create regular user accountsstay up late (eg. 2 a.m.  #Download, study, and ) to manually run the following a shell script. Issue the command:<br><b><code><span style=" pointerto terminate processes or to re-events:none;cursor:default;color:#3366CC;font-size:1.2em;">wget https://scs.senecacboot Linux servers.Database files (tables) are used to provide instructions onhow frequent shell scripts or commands can be run.ca/~murray.saul/user-create.bash</span></code></b>#Try The '''cron''' daemon is used to refer to understand what these Bash Shell scripts do, files and then to run the script as rootthem on a pre-determined basis. After running the shell script, view the contents of The term '''cron''' comes from the old word '''chronograph'''meaning a special type of watch (actually a '/home'stop-watch'' directory ) to confirmhelp monitor and schedule routine tasks.

<li value="85">Save, Quickly view the tutorial about the <b>[http://code.tutsplus.com/tutorials/scheduling-tasks-with-cron-jobs--net-8800 Using crontab]</b> file to understand the purpose of this file and how to basically set permissions, and then up a schedule to run that a shell script .</li> <li>Issue the following command to setup a crontab entry for root:<br><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">crontab -e</span></code></b></li><li>Enter the input text file following line in order to run at 6:00 on the first day of every month:<br><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">0 6 1 * * /root/monitor-disk-space.bash #Runs first day of each month (6:00 am)</span></code></b></li><li>'''user-data.txtSave'''the crontab entry. Did it work? Try running the script without an argument - What did it do? </li><li>You have completed lab4. Proceed to Completing The Lab, and follow Confirm that the entry was properly saved by issuing the instructions for following command:<br><b><code><span style="lab signpointer-offevents:none;cursor:default;color:#3366CC;font-size:1.2em;".>crontab -l</span></code></b></li></ol>

{{Admon/important|Time for a new backup, INCLUDING YOUR VIRTUAL HARD DRIVE!|If you have successfully completed this lab, make a new backup of your virtual machines. Remember to also make a backup of the new second virtual disk drive on <br><br>''centos1'' Virtual hard-- you now have two virtual disks on ''centos1'', and therefore two drives created in this lab are image files, and therefore will now need two backup filesto be backed up as well!'''.}}

::<ol><li><span style="color:green;font-size:1.5em;">&#x2713;</span> x:'''centos2''' VM:<blockquote><ul><li>'''Logical Volume''', '''Physical Volume''', and '''Volume Group''' information </li><li>Contents of '''/etc/fstab''' file</li><li>Proof that '''/archive''' has been mounted</li></ul></blockquote><li><span style="color:green;font-size:1.5em;">&#x2713;</span> x:'''centos3''' VM:<blockquote><ul><li>Proof of virtual hard disk creation</li><li>'''Logical Volume''', '''Physical Volume''', and '''Volume Group''' information </li></ul></blockquote></li><li><span style="color:green;font-size:1.5em;">&#x2713;</span> x:'''c7host''' Machine:<span style="colorblockquote><ul><li>Proof of creation of the shell script:green;font'''monitor-disk-size:1space.5em;"bash'''</li><li>Crontab entry for '''root''' account</li></ul>&#x2713;</spanblockquote><li> x::<span style="color:green;font-size:1.5em;">&#x2713;</span> x'''Lab5''' log-book filled out.</li></ol> 

= Preparing for the = Practice For Quizzes , Tests, Midterm &amp; Final Exam ==

# How do you create a an LV?# How do you delete resize an LV?

# How can you determine if a partition has been mounted onto a system?# How can you unmount an existing partition from the file-system?# How can you temporarily mount a partition on a file-system?# How can you permanently mount a partition on a file-system upon boot-up?# What is are the purpose separate elements (fields) of the '''/etc/fstab'''file?# Describe the tools that a Linux system administrator have to monitor disk space usage.