HDD/SSD configuration

HDD only

This basic configuration requires a dedicated disk for each metadata server.

HDD-only configuration
Nodes 1-5 (base)			Nodes 6+ (extension)
Disk #	Disk type	Disk roles	Disk #	Disk type	Disk roles
1	HDD	System	1	HDD	System
2	HDD	MDS	2	HDD	CS
3	HDD	CS	3	HDD	CS
…	…	…	…	…	…
N	HDD	CS	N	HDD	CS

HDD + system SSD (no cache)

This configuration is good for creating capacity-oriented clusters.

HDD + system SSD (no cache) configuration
Nodes 1-5 (base)			Nodes 6+ (extension)
Disk #	Disk type	Disk roles	Disk #	Disk type	Disk roles
1	SSD	System, MDS	1	SSD	System
2	HDD	CS	2	HDD	CS
3	HDD	CS	3	HDD	CS
…	…	…	…	…	…
N	HDD	CS	N	HDD	CS

HDD + SSD

This configuration is good for creating performance-oriented clusters.

HDD + SSD configuration
Nodes 1-5 (base)			Nodes 6+ (extension)
Disk #	Disk type	Disk roles	Disk #	Disk type	Disk roles
1	HDD	System	1	HDD	System
2	SSD	MDS, cache	2	SSD	Cache
3	HDD	CS	3	HDD	CS
…	…	…	…	…	…
N	HDD	CS	N	HDD	CS

SSD only

This configuration does not require SSDs for cache.

In this configuration, network latency defines more than half of overall performance, so make sure that the network latency is minimal. One recommendation is to have one 10Gbps switch between any two nodes in the cluster.

SSD-only configuration
Nodes 1-5 (base)			Nodes 6+ (extension)
Disk #	Disk type	Disk roles	Disk #	Disk type	Disk roles
1	SSD	System, MDS	1	SSD	System
2	SSD	CS	2	SSD	CS
3	SSD	CS	3	SSD	CS
…	…	…	…	…	…
N	SSD	CS	N	SSD	CS

HDD + SSD (no cache), 2 tiers

In this configuration example, tier 1 is for HDDs without cache and tier 2 is for SSDs. Tier 1 can store cold data (for example, backups), tier 2 can store hot data (for example, high-performance virtual machines).

HDD + SSD (no cache) 2-tier configuration for nodes 1-5 (base)
Disk #	Disk type	Disk roles	Tier
1	SSD	System, MDS
2	SSD	CS	2
3	HDD	CS	1
…	…	…	…
N	HDD/SSD	CS	1/2

HDD + SSD (no cache) 2-tier configuration for nodes 6+ (extension)
Disk #	Disk type	Disk roles	Tier
1	SSD	System
2	SSD	CS	2
3	HDD	CS	1
…	…	…	…
N	HDD/SSD	CS	1/2

HDD + SSD, 3 tiers

In this configuration example, tier 1 is for HDDs without cache, tier 2 is for HDDs with cache, and tier 3 is for SSDs. Tier 1 can store cold data (for example, backups), tier 2 can store regular virtual machines, and tier 3 can store high-performance virtual machines.

HDD + SSD 3-tier configuration for nodes 1-5 (base)
Disk #	Disk type	Disk roles	Tier
1	HDD/SSD	System
2	SSD	MDS, T2 cache
3	HDD	CS	1
4	HDD	CS	2
5	SSD	CS	3
…	…	…	…
N	HDD/SSD	CS	1/2/3

HDD + SSD 3-tier configuration for nodes 6+ (extension)
Disk #	Disk type	Disk roles	Tier
1	HDD/SSD	System
2	SSD	T2 cache
3	HDD	CS	1
4	HDD	CS	2
5	SSD	CS	3
…	…	…	…
N	HDD/SSD	CS	1/2/3