Brief overview of Red Hat Gluster Storage

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Red Hat Gluster Storage (GlusterFS )
Bipin Kunal
SME - RHGS (GlusterFS)

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Agenda
● What is Red Hat Gluster Storage?
● What is GlusterFS?
● Architecture
● Features
● Concepts
● Use Cases

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What is Red Hat Gluster Storage?
●
Red Hat Gluster Storage is a software only, scale-out storage
solution.
●
GlusterFS, a key building block of Red Hat Gluster Storage, is based
on a stackable user space design and can deliver exceptional
performance for diverse workloads.

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What is GlusterFS?
●
A general purpose scale-out distributed file system.
●
Aggregates storage exports over network interconnect to provide a
single unified namespace.
●
Filesystem is stackable and completely in userspace.
●
Layered on disk file systems that support extended attributes.

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Typical GlusterFS Deployment
● Global
namespace
● Scale-out storage
building blocks
● Supports
thousands of
clients
● Access using
GlusterFS native,
NFS, SMB and
HTTP protocols

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GlusterFS Architecture – Foundations
●
Software only, runs on commodity hardware
●
No external metadata servers
●
POSIX compliant

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Features

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Design Features
●
Elasticity
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No Metadata with the Elastic Hashing Algorithm
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Scalability
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High Availability
●
Simple Management
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Modular and Stackable Design

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Features from User Prospective
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Bit-rot detection
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Data tiering
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Data Replication and Distribution
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Geo-replication
●
Snapshot
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IO and Management Encryption
●
Containerized GlusterFS

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GlusterFS Architecture – Foundations
●
Software only, runs on commodity hardware
●
No external metadata servers
●
POSIX compliant

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Concepts

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GlusterFS concepts – Trusted Storage Pool
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Trusted Storage Pool (cluster) is a collection of storage servers.
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Trusted Storage Pool is formed by invitation – “probe” a new
member from the cluster and not vice versa.
●
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Membership information used for determining quorum.
●
Members can be dynamically added and removed from the pool.

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GlusterFS concepts – Trusted Storage Pool
Node2
Probe
Probe
accepted
Node 1 and Node 2 are peers in a trusted storage pool
Node2Node1
Node1

14. 05/04/16 The Future of Gluster.org - John Mark Walker
GlusterFS concepts – Trusted Storage Pool
Node1 Node2 Node3Node2Node1 Trusted Storage Pool
Node3Node2Node1
Detach

15. 05/04/16 The Future of Gluster.org - John Mark Walker
 A brick is the combination of a node and an export directory – for e.g.
hostname:/dir
 Each brick inherits limits of the underlying filesystem
 No limit on the number bricks per node
 Ideally, each brick in a cluster should be of the same size
/export3
/export3
/export3
Storage Node
/export1
Storage Node
/export2
/export1
/export2
/export4
/export5
Storage Node
/export1
/export2
3 bricks 5 bricks 3 bricks
GlusterFS concepts - Bricks

16. 05/04/16 The Future of Gluster.org - John Mark Walker
GlusterFS concepts - Volumes
● A volume is a logical collection of bricks.
● Volume is identified by an administrator provided name.
● Volume is a mountable entity and the volume name is provided
at the time of mounting.
● mount -t glusterfs server1:/<volname> /my/mnt/point
● Bricks from the same node can be part of different volumes

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GlusterFS concepts - Volumes
Node2Node1 Node3
/export/brick1
/export/brick2
/export/brick1
/export/brick2
/export/brick1
/export/brick2
music
Videos

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Volume Types
●
Type of a volume is specified at the time of volume creation
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Volume type determines how and where data is placed
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Following volume types are supported in glusterfs:
a) Distributed
b) Replicated
c) Distributed Replicated
d) Dispersed
e) Distributed Dispersed

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Distributed Volume
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Distributes files across various bricks of the volume.
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Directories are present on all bricks of the volume.
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Single brick failure will result in loss of data availability.

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How does a distributed volume work?
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Uses Davies-Meyer hash algorithm.
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A 32-bit hash space is divided into N ranges for N bricks.
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At the time of directory creation, a range is assigned to each directory.
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During a file creation or retrieval, hash is computed on the file name.
This hash value is used to locate or place the file.
●
Different directories in the same brick end up with different hash
ranges.

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How does a distributed volume work?

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How does a distributed volume work?

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Replicated Volume
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Synchronous replication of all directory and file updates.
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Provides high availability of data when node failures occur.
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Transaction driven for ensuring consistency.
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Number of replicas supported are 2 and 3.

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Replicated volume

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Distributed Replicated Volume
● Distribute files across replicated bricks
– Number of bricks must be a multiple of the replica count
– Ordering of bricks in volume definition matters
● Scaling and high availability
● Load Balancing
● Most preferred model of deployment currently.

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Distributed Replicated Volume

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Dispersed Volume
These are based on Erasure Coding
This allow recovery on data even if one or more bricks fail
Lesser disk space utilization that Distributed-Replicated

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Distributed Dispersed Volume

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FUSE based native access

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NFS access

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Use Cases
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Media Storage and streaming
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Disaster Recovery (Geo-Replication)
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Efficiently and cost-effectively store virtual machine images
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Collaboration and control data access anywhere, anytime

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Q & A
Thank You