362.2 Cluster Storage Access (weight: 3)

Tech Tutorial: 362.2 Cluster Storage Access (weight: 3) #

Introduction #

In modern computing environments, where data availability and scalability are crucial, clustering technology plays an essential role. Cluster storage access is a critical component in managing and maintaining data across different nodes in a cluster, ensuring data is available and consistent. This tutorial will cover the key areas and utilities necessary for effective cluster storage access, focusing on Linux environments.

Exam Objective #

The objective of this section is to understand how to manage and access storage within a cluster, including the configuration and management of shared storage and distributed file systems.

Key Knowledge Areas #

  • Understanding of shared storage technologies (iSCSI, Fibre Channel)
  • Configuration and management of GFS2 file systems
  • Awareness of distributed storage solutions (Ceph, GlusterFS)

Utilities #

  • iscsiadm
  • multipath
  • pcs
  • parted
  • mkfs.gfs2
  • mount
  • ceph
  • gluster

Step-by-Step Guide #

1. Configuring iSCSI Initiator #

The iSCSI protocol allows block-level data storage over IP networks. Here’s how you can configure an iSCSI initiator on a Linux system:

Install the necessary tools: #

sudo apt-get install open-iscsi

Discover targets: #

sudo iscsiadm -m discovery -t st -p [target_IP]

Connect to a target: #

sudo iscsiadm -m node -T [target_name] -p [target_IP] -l

2. Setting Up Device Multipathing #

Device multipathing ensures continuous data access even if one path fails. Here’s how to set it up:

Install multipath-tools: #

sudo apt-get install multipath-tools

Configure multipath: #

Edit /etc/multipath.conf to set up aliases and blacklist non-multipath devices.

Start the multipath daemon: #

sudo service multipath-tools restart

List and manage paths: #

multipath -ll

3. Managing GFS2 File System #

GFS2 is a shared disk file system for Linux used in clusters.

Install GFS2 tools: #

sudo apt-get install gfs2-utils

Create a GFS2 file system: #

sudo mkfs.gfs2 -p lock_dlm -t mycluster:mygfs2 -j 2 /dev/mapper/mpathX

Mount the GFS2 file system: #

sudo mount -t gfs2 -o noatime,nodiratime /dev/mapper/mpathX /mnt/gfs2

4. Introduction to Ceph and GlusterFS #

These are distributed storage systems providing excellent scalability and redundancy.

Install Ceph: #

sudo apt install ceph

Deploy a Ceph Monitor and a Ceph OSD (Object Storage Daemon): #

ceph-deploy new node1 node2 node3
ceph-deploy mon create-initial
ceph-deploy osd create --data /dev/sdb node1

Install GlusterFS: #

sudo apt-get install glusterfs-server

Configure a GlusterFS volume: #

sudo gluster volume create gv0 replica 3 node1:/data/gv0 node2:/data/gv0 node3:/data/gv0 force
sudo gluster volume start gv0

Conclusion #

Understanding and implementing cluster storage access mechanisms is crucial for managing data in a clustered environment. By using tools and technologies like iSCSI, multipathing, GFS2, Ceph, and GlusterFS, administrators can ensure that storage is both scalable and reliable. This tutorial provides the foundational knowledge and practical examples to help you manage cluster storage effectively.