Skip to content

Latest commit

 

History

History
221 lines (153 loc) · 11 KB

LFCE_StorageManagement.md

File metadata and controls

221 lines (153 loc) · 11 KB

LFCE: Storage Management

  1. Manage advanced LVM configuration

  2. Identify storage devices using block device attributes

  3. Manage Linux file system features and flags

  4. Implement and configure remote block storage devices

  5. Implement and configure network shares

Manage advanced LVM configuration

  • See the LFCS info and read this article

  • Logical volumes can be created with some advanced options as well. Some options that you may wish to consider are:

    –type: This specifies the type of logical volume, which determines how the logical volume is allocated. Some of the available types will not be available if there are not enough underlying physical volumes to correctly create the chosen topography. Some of the most common types are:

    • linear: The default type. The underlying physical devices used (if more than one) will simply be appended to each other, one after the other.

    • striped: Similar to RAID 0, the striped topology divides data into chunks and spread in a round-robin fashion across the underlying physical volumes. This can lead to performance improvements, but might lead to greater data vulnerability. This requires the -i option described below and a minimum of two physical volumes.

    • raid1: Creates a mirrored RAID 1 volume. By default, the mirror will have two copies, but more can be specified by the -m option described below. Requires a minimum of two physical volumes.

    • raid5: Creates a RAID 5 volume. Requires a minimum of three physical volumes.

    • raid6: Creates a RAID 6 volume. Requires a minimum of four physical volumes.

    -m: Specifies the number of additional copies of data to keep. A value of “1” specifies that one additional copy is maintained, for a total of two sets of data.

    -i: Specifies the number of stripes that should be maintained. This is required for the striped type, and can modify the default behavior of some of the other RAID options.

    -s: Specifies that the action should create a snapshot from an existing logical volume instead of a new independent logical volume.

    Examples:

    • To create a striped volume of 10G, you must specify at least two stripes stripe size 10MB. This topology and stripe count requires a minimum of two physical volumes with available capacity:

      sudo lvcreate --type striped -i 2 -L 10G -I 10M -n striped_vol LVMVolGroup

    • To create a mirrored volume, use the raid1 type. If you want more than two sets of data, use the -m option. This example uses -m 2 to create a total of three sets of data (LVM counts this as one original data set with two mirrors). You will need at least three physical volumes for this to succeed:

      sudo lvcreate --type raid1 -m 2 -L 20G -n mirrored_vol LVMVolGroup

    • To create a snapshot of a volume, you must provide the original logical volume to snapshot instead of the volume group. Snapshots do not take up much space initially, but grow in size as changes are made to the logical volume it is tracking:

      sudo lvcreate -s -L 10G -n snap_test LVMVolGroup/test

      Note: To revert a logical volume to the point-in-time of a snapshot, use:

      sudo lvconvert --merge LVMVolGroup/snap_test

    • Create VG using /dev/sda1 /dev/sda2 /dev/sda3 with extend size of 5MB.

    • Extend LVM with 12MB, no fs created.

Identify storage devices using block device attributes

  • Use the following commands and their options: blkid, lsblk, etc.

    blkid -t TYPE=ext4 -> Search by type.

    blkid -o list -> Show additional info for every device like: fs_type, label, mount point.

    blkid -l -t LABEL=STEN_XFS -> Search for specific label.

  • You can also use the directories under /dev/disk to filter by id, label, path or uuid.

  • udevadm info -a -p /sys/block/sda -> To see a lot of info for sda partition.

Manage Linux file system features and flags

  • Check some commands in LFCS repo

  • man mkfs.ext4 -> and search for -E which is the flag for extended options.

  • mkfs.xfs -f -l logdev=/dev/sde1,size=1000b /dev/sde2 -> Make xfs fs and separate data from logs on different partitions.

  • mount -o logdev=/dev/sde1 /dev/sde2 /tmp/mount_point -> Use this mount.

Implement and configure remote block storage devices

  • The server can export local storage to remote clients. We are dedicating the device to the remote system.

    • On the server:

      • yum install targetcli - Install the CLI tool.
      • systemctl enable target --now - Enable and start the service.
      • targetcli
      • /backstores/fileio create file1 /tmp/disk.img 200M write_back=false
      • cd iscsi & create iqn.2018-04.com.localnet.filedisk1 - Create the target.
      • cd /iscsi/iqn.2018-04.com.localnet.filedisk1/tpg1/
      • luns/ create /backstores/fileio/file1 - Create the LUN.
      • acls/ create iqn.2018-04.com.localnet:osboxes - Create the ACL.
      • cd /iscsi/iqn.2018-04.com.localnet.filedisk1/tpg1/acls/iqn.2018-04.com.localnet:osboxes
      • set auth userid=osboxes
      • set auth password=password
      • exit - Use exit to save the above config.
      • sudo netstat -atn | grep 3260
      • sudo firewall-cmd --permanent --add-service=iscsi-target; sudo firewall-cmd --reload

    • On the client:

      • yum install iscsi-initiator-utils
      • systemctl enable iscsid --now
      • systemctl enable iscsi --now
      • sudo vi /etc/iscsi/initiatorname.iscsi - and add the following to the file: 
        InitiatorName=iqn.2018-04.com.localnet:osboxes
      • sudo vi /etc/iscsi/iscsid.conf and change the following lines: 
        node.session.auth.authmethod = CHAP
node.session.auth.username = osboxes
node.session.auth.password = password
      • systemctl restart iscsi; systemctl restart iscsid
      • sudo iscsiadm --mode discovery --type sendtargets --portal 192.168.0.105 - not working
      • sudo iscsiadm -m node -T iqn.2018-04.com.localnet.filedisk1 -p 192.168.0.105:3260 --login 
        # vi /etc/fstab
UUID="XXXXXXXXXX" /storage ext4  _netdev  0  0
      • lsblk --scsi

      All above info can be found here: https://unixcop.com/iscsi-target-and-initiator-installation-on-centos8-rhel8/

  • For more detailed info check the following Linked Learning course: https://www.linkedin.com/learning/linux-storage-systems/configure-remote-block-storage-devices

Implement and configure network shares

  • Have a look at the info in LFCS repo

  • NFS additional info:

    /etc/exports.d/*exports -> Is directory where you can add additional exports as seperate files.

    /var/lib/nfs/etab -> List of available shares.

    /etc/sysconfig/nfs -> Server and Client configuration file.

    Structure of the /etc/exports file:

    export host1(options) host2(options) host3(options)

    nfsstat & nfsiostat -> Provide NFS statistics.

    For more info see: man nfs

  • Samba additional info:

    • Samba is more complex than NFS.

    • testparm - check an smb.conf configuration file for internal correctness.

    • For more info check:

      • man samba
      • man smb.conf -> Have good examples.
      • /etc/samba/smb.conf.example -> Example configuration file.

    • Example:

      sudo mkdir sambapublic
sudo semanage boolean samba_export_all_ro --on -m
sudo semanage boolean samba_export_all_rw --on -m
sudo chown nobody:nobody /home/sambapublic/
sudo chmod -R 775 /home/sambapublic/
sudo semanage fcontext -at public_content_rw_t "/home/sambapublic(/.*)?"
restorecon /home/sambapublic
ls -dZ /home/sambapublic/
sudo firewall-cmd --permanent --add-service samba
sudo firewall-cmd --reload
sudo vi /etc/samba/smb.conf

# Append the following to the smb.conf file:
[sambapublic]
        comment = public samba share
        path = /home/sambapublic
        writable = yes
        public = yes
        #read only = no #Other options
        #guest ok = yes
        #valid users = vagrant

testparm # check the smb.conf file.
systemctl start smb.service
# Test locally
smbclient -L //localhost # when promped for password hit enter.
\> quit
smbclient //locahost/sambapublic # when promped for password hit enter.
\> help tar
\> mkdir testdir

# On remote host:
mount -t cifs -o guest,noperm //SAMBA_SERVER_IP/sambapublic /home/sambapublic_local
# use guest option for not asking for permissions.

    • When using "valid users" option you can do the following additional steps:

      • sudo pdbedit -L -> Check if your account already exists among smbdclients.
      • sudo smbpasswd -a myaccount -> If the account is not there add it.
      • sudo pdbedit -x -u myaccount -> If already exists, you have to delete first and add it again as previous command.

    • Exercise: Create filesystem create user xxxxx allow that user

  • If you have access to Linked Learning have a look at the following courses:

Back to top of the page: ⬆️