Create and configure file systems

Question 1

to create a file system

Answer 1

use mkfs(may ways to use it depending on the file system type, ie)
# mkfs -t ext4 /dev/sdb1
# mkfs.ext4 /dev/sdb1

Question 2

tune2fs

Answer 2

helps us control how many times a filesystem can be mounted before a filesystem check needs to run on it.
Command to run after you’ve formatted a partition
#tune2fs -m0 /dev/sdb1

Question 3

check info on a filesystem

Answer 3

tune2fs -l /dev/sdb1

Question 4

check a filesystem

Answer 4

fsck /dev/sdb1 do not run on a mounted filesystem

Question 5

to create an xfs filesystem

Answer 5

mkfs.xfs /dev/sdb2

Question 6

to create a vfat filesystem

Answer 6

mkfs.vfat /dev/sdb3

Question 7

To get details about a file system type

Answer 7

dumpe2fs /dev/sdb2

Question 8

to repair an unmounted filesystem consistency (xfs filesystem)

Answer 8

xfs_repair /dev/sdb2

Question 9

to get details about a mount xfs filesystem

Answer 9

xfs_info /dev/sdb2

Question 10

to repair an unmounted vfat filesystem

Answer 10

fsck.vfat /dev/sdb3

Question 11

steps to mount a filesystem

Answer 11

1 - create a directory
#mkdir /mnt/data
2. mount the filesystem
# mount -t ext4 /dev/sdb1 /mnt/data
3. check that it's mounted
# mount | grep data
4. add entry to /etc/fstab to mount after reboot(permanent)

Question 12

What’s needed to mount an NFS(network file system) filesystem

Answer 12

Install the NFS client package:
# yum install -y nfs-utils

Activate the nfs-idmap service at boot:
# systemctl enable nfs-idmap

Note: The nfs-idmap service is required by NFSv4 but doesn’t allow you any UID/GID mismatches between clients and server. It is only used when setting ACL by names or to display user/group names.
All permission checks are still done with the UID/GID used by the server (see this thread about nfs-idmap for more details).

Start the nfs-idmap service:
# systemctl start nfs-idmap

Edit the /etc/fstab file and add the following line:
nfsserver:/home/tools /mnt nfs4 defaults 0 0

Execute the /etc/fstab file configuration:
# mount -a

To check the current configuration, type:
# mount | grep nfsserver

To unmount the NFS mounted directory
# umount /mnt

Note: if you get a message like “/mnt: device is busy”, to check that you are not in the mounted directory and no process is using it, type:
# umount /mnt

Question 13

show which nfs filesystem is available on a system

Answer 13

showmount -e [ip or hostname]

Question 14

mount nfs to a local directory

Answer 14

# mkdir /mnt/nfs
# mount -t nfs ip:/srv/nfs /mnt/nfs   
you could also put hostname instead of ip
For permanent entry add to /etc/fstabname:/srv/nfs    /mnt/nfs    nfs   _netdev    0 0

Question 15

for nfs use _netdev instead of defaults

Answer 15

It tells the mount command to wait for the network services to come up prior to mounting the share(to prevent hanging)

Question 16

CIFS network file system

Answer 16

Install the samba client packages
#yum install -y cifs-utils
# yum install -y samba-client

Let’s assume that the /shared directory is exported by the smbserver server.
Edit the /etc/fstab file and add the following line:
//smbserver/shared /mnt cifs rw,username=user01,password=pass 0 0

Execute the /etc/fstab file configuration:
# mount -a

Question 17

Cifs permanent mounting

Answer 17

//smbserver/shared    /mnt   cifs   rw,user,credentials=/root/secret.txt   0 0
in /root/secret.txtadd username=visitor
password=Welcome123$

Question 18

to see which shares are available on a cifs server

Answer 18

smbclient -U username -L [hostname/IP]

Question 19

To login to the remote cifs share

Answer 19

smbclient -U username //ip/shared

Question 20

You can run windows command when you’ve logged into a cifs shared

Answer 20

smb:> get filename.txt download a filesmb: > put file1.txt upload a file

Question 21

To mount a cifs share(temporarily)

Answer 21

# mount -t cifs -o user= //IP-or-host/shared /mnt/sharedreview man mount.cifs
You can also do it from the desktopGo to Places -> connect to serverChange the service type to window share, enter info, then click connect

Question 22

To increase the size of a logical volue

Answer 22

use the lvextend command. When you extend the logical volume, you can indicate how much to extend the volume, or how large you want it to be after you extend it.

Question 23

The following command extends the logical volume /dev/myvg/homevol to 12GB

Answer 23

lvextend -L 12G /dev/myvg/homevol

Question 24

The following command adds another gigabyte to the logical volume

Answer 24

lvextend -L +1G /dev/myvg/homevol

Question 25

The following command extends the logical volume called testlv to fill all of the unallocated space in the volume group myvg

Answer 25

lvextend -l +100% Free /dev/myvg/testlv

Question 26

adding a filesystem on a logical volume

Answer 26

#mkfs.ext4 /dev/vg_new/lv_new
#mkdir /extra   directory to mount logical volume
add entry to /etc/fstab/dev/vg_new/lv_new  /extra  ext4   defaults  0 0
# mount -a

Question 27

To grow the logival volume lvresize can also be used

Answer 27

lvresize -L 900M /dev/vg_new/lv_newThen resize the filesystem# resize2fs /dev/vg_new/lv_new

Question 28

To shrink the logical volume(make sure to have a backup)

Answer 28

#unmount extra
#fsck -f /dev/vg_new/lv_new
#resize2fs /dev/vg_new/lv_new 800MB
#lvresize -L 800MB /dev/vg_new/lv_new

Question 29

Set-GID

Answer 29

set-gid directories are used for group collaboration. Everything that is created in a directory with that special permission bit, is automatically owned by the group

Question 30

how to apply the set-git permission

Answer 30

applying the set-git permission on a directory by add a 2 before the standard permission set
# chmod 2755 share
-Then you’ll see the directory has a permission set that contains a ‘s’ now in place of the x for group
-the character based way to setup a set-gid directory
#chmod g+s share

Question 31

ACL(Access Control Lists)

Answer 31

- to use ACLs first the acl property needs to be enabled on the partition. run the mount command to check
# mount
- to change and turn on ACL make changes in /etc/fstab before
/dev/mapper/vg_rhel01/lv_root   /  ext4   defaults   1 1 after
/dev/mapper/vg_rhel01/lv_root   / ext4    defaults,acl 1 1
Then you need to remount or restartto remount
# mount -o remount /
Without adding entry to fstab(this isn't permanent)
# mount -o remount -o acl /dev/...

Question 32

to check acl on a directory or file

Answer 32

use the getfacl command#getfacl file

Question 33

to add user acl to a file or directory

Answer 33

setfacl -m u:user2:rw install.log m = modify

Question 34

to add a group acl on a file

Answer 34

setfacl -m g:IT:rwx install.log

Question 35

to remove all acls on a file

Answer 35

setfacl -b file1 -b for remove all

Question 36

Note pay attention to “other” users in regard to ACL

Answer 36

#setfacl -m o:rwx file1   gives rwx to other, but you cannot use -x or -b to remobe such a change. The only way to remove this acl is either the following command:
#setfacl -m o:www file1    or
#chmod o-rwx file1

Question 37

to remove permissions allowed to the user bob(-x for remove)

Answer 37

setfacl -x u:bob file1

Question 38

Apply ACL recursively

Answer 38

setfacl -R -m u:user1:rwx file1

Question 39

The following command cancels ACL settings for a user recursively

Answer 39

setfacl -R -x u:user1 file1

Question 40

The mask in regard to ACL

Answer 40

The mask associated with ACL limits the permission available on a file. In other words, with a mask of --r, you can try all other privileges, but all that can be set with that mask is read privileges. The command to set the mask:
#setfacl -m mask:r-- acltest.txt

Question 41

To set a default ACL

Answer 41

Add d: before the rule and specify a directory instead of a filename
#setfacl -m d:o:rx /share

Question 42

Man in regard to ACL

Answer 42

review these man pages
#man acl
#man getfacl
#man setfacl
#man star   the star utility