Virtual SAN is a hyper-converged storage platform that is built into the ESXi hypervisor. It aggregates locally attached flash and disk drives from each ESXi host in a cluster to provide a shared datastore. Virtual SAN provides dynamic capacity and performance scaling. It utilizes storage policies to provide per-VM storage service levels from the single shared datastore. Virtual SAN simplifies storage management by automating control of storage capacity, performance, and availability based on application needs.

1. © 2014 VMware Inc. All rights reserved.
VMware Virtual SAN
It changes everything
Duncan Epping
Principal Architect – R&D

2. Virtual SAN Technical Walkthrough
1 Introduction
2 Requirements
3 Architecture
4 Configuration Walkthrough
5 Virtual Machine Provisioning Operations
2

3. VMware Virtual SAN
• Storage scale out architecture
built into the hypervisor
• Aggregates locally attached
storage from each ESXi host in
a cluster
• Dynamic capacity and
performance scalability
• Flash optimized storage solution
• Fully integrated with vSphere
and interoperable:
• vMotion, DRS, HA, VDP, VR …
• VM-centric data operations
3
vSphere + Virtual SAN
Hard disksHard disks
SSD SSD Hard disks
SSD
…
Virtual SAN Shared
Datastore
• Hypervisor-Convergedstorage platform

4. Storage Policy-Based
Management
VSAN Shared
Datastore
Simplifies and Automates Storage Management
4
Per VM storage service levels from a single self-tuning datastore
Capacity
Performance
Availability
Per VM Storage
Policies
Policies set based on
application needs
vSphere + VSAN
SLAs
Software automates
control of service levels

5.  No overprovisioning
 Less resources, less time
 Easy to change
Today
5. Consume from pre-
allocated bin
4. Select appropriate bin
3. Expose pre-allocated
bins
2. Pre-allocate static bins
1. Pre-define storage
configurations
1. Define storage policy
2. Apply policy at VM
creation
VSAN
VSAN
Shared
Datastore
Resource and data service are
automatically provisioned and
maintained
✖ Overprovisioning (better safe
than sorry!)
✖ Wasted resources, wasted time
✖ Frequent Data Migrations
Virtual SAN Puts The App In Charge
Simpler and automated storage management through application centric
approach
5

6. 6
Management Clusters
Use Cases
Backup and DR
Target
DMZ / Isolated
Tier 2 / Tier 3
Test / Dev / Staging
Private cloud
Virtual Desktop
ROBO
VDI
Site A Site B
vSphere
VSAN

7. VMware Virtual SAN
Hardware Requirements

8. Two Ways to Build a Virtual SAN Node
8
Completely Hardware Independent
1. Virtual SAN Ready
Node
…with multiple options available
at GA + 30
Preconfigured server ready to
use Virtual SAN…
2. Build Your
Own
…using the Virtual SAN
CompatibilityGuide*
Choose individual
components …
Flash: SSD or PCIe
SAS/NL-SAS/ SATA
HDDs
Any Server on
vSphere Hardware
Compatibility List
HBA/RAID Controller

9. Hardware Requirements
9
Any Server on the VMware
Compatibility Guide
• SSD, HDD, and Storage Controllers must be listed on the VMware Compatibility Guide for VSAN
http://vmwa.re/vsanhcl
1Gb/10Gb NIC
SAS/SATAControllers (RAID Controllers
must work in “pass-through” or RAID0”
mode
SAS/SATA/PCIe
SSD
SAS/NL-SAS/SATA
HDD
At least 1
of each
ESXi Boot device: 4GB to 8GB USB/SD

10. Flash Based Devices
In Virtual SAN ALL write operations always go directly to the Flash tier,
and most reads will come from Flash
Flash based devices serve two purposes in Virtual SAN
1. Non-volatile Write Buffer (30%)
– Writes areacknowledged when they enter prepare stage on SSD.
– Reduces latency for writes
2. Read Cache (70%)
– Cache hits reduces read latency
– Cache miss – retrieve data from HDD
Choice of hardware is the #1 performance
differentiator between Virtual SAN
configurations.
10

11. Flash Based Devices
• VMware SSD Performance Classes
– Class A: 2,500-5,000 writes per second
– Class B: 5,000-10,000 writes per second
– Class C: 10,000-20,000writes per second
– Class D: 20,000-30,000writes per second
– Class E: 30,000+ writes per second
• Endurance
– 10 Drive Writes per Day (DWPD) for 5 years, and
– Random write endurance up to 3.5 PB on 8KB transfer size per NAND
module, or 2.5 PB on 4KB transfer size per NAND module
11

12. Flash Capacity Sizing
 The general recommendation for sizing Virtual SAN's flash capacityis to have
10% of the anticipated consumed storage capacity before the Numberof
Failures To Tolerate is considered
 Total flash capacity percentage should be based on use case, capacity and
performance requirements
– 10% is a general recommendation, could be too much or it may not be
enough
MeasurementRequirements Values
Projected VM space usage 50GB
Projected number of VMs 100
Total projected space consumption per VM (50% of 50GB) x 100 = 2,500 GB = 2.5 TB
Target flash capacity percentage 10%
Total flash capacity required 2.5TB x .10 = 250 GB
12

13. Magnetic Disks (HDD)
• SAS/NL-SAS/SATA HDDs supported
– 7200 RPM for capacity
– 10000 RPM for performance
– 15000 RPM for additional performance
• NL SAS will provide higher HDD controller queue depth at same drive
rotational speed and similarprice point
– NL SAS recommended if choosing between SATA and NL SAS
• When doing the design, take “overhead”, “slack space” and “failures to
tolerate” in to account!
13

14. Storage Controllers
• SAS/SATA Storage Controllers
– Pass-through or “RAID-0” mode supported
– Also sometimes referredto as “Virtual SAN SAS” or “Virtual SAN SATA”
• Performance using RAID-0 mode is controller dependent
– Check with your vendor for SSD performance behind a RAID-controller
– Disable controller cache
• Storage Controller Queue Depth matters
– Higher storage controller queue depth will increase performance
• Validate number of drives supported for each controller
14

15. Network
• 1Gb / 10Gb supported
– 10Gb shared with NIOC for QoS will support
most environments
– If 1GB then recommend dedicated links for Virtual SAN
• Jumbo Frames will provide nominal performance increase
– Enable for greenfield deployments, could lower CPU overhead
• Virtual SAN supports both VSS & VDS
– NIOC requires VDS
– Nexus 1000v – Should work but hasn't been fully tested
• Network bandwidth performance has more impact on host
evacuation, rebuild times than on workload performance
15

16. ESXi Boot Devices
 What installation device to use:
– Depends on amount of host memory
– Up to 512 GB
– Use of SD/USB devices or magnetic disks as the ESXi
boot supported
– 512 GB or greater
– Only supported when using a magnetic disk or solid
stated disk as the ESXi boot device
16

17. VMware Virtual SAN
Technical Characteristics and Architecture

18. Technical Characteristics
Virtual SAN is a cluster level feature similar to:
– vSphere DRS
– vSphere HA
– Virtual SAN
Deployed, configured and manage from vCenter through the
vSphere Web Client (ONLY!).
– Radically simple
• Configure VMkernel interface for Virtual SAN
• Enable Virtual SAN by clicking Turn On
18

19. Virtual SAN Implementation Requirements
• Virtual SAN requires:
– Minimum of 3 hosts in a cluster
configuration
– All 3 host must contribute
storage
• vSphere 5.5 U1 or later
– Maximum of 32 hosts
– Locally attached disks
• Magnetic disks (HDD)
• Flash-based devices (SSD)
– Network connectivity
• 1GB Ethernet
• 10GB Ethernet (preferred)
19
VSAN 10GbE netw ork
esxi-01 esxi-02 esxi-03
Virtual SAN and HA/DRS Cluster

20. Virtual SAN Constructs and Artifacts
New Virtual SAN constructs, artifacts and
terminologies:
• Disk Groups
• VSAN Datastore
• Objects
• Components
• Virtual SAN Network
20

21. Virtual SAN Disk Groups
• Virtual SAN uses the concept of disk groups to pool together flash
devices and magnetic disks as single management constructs
• Disk groups are composed of at least 1 flash device and 1-7 magnetic
disks
– Flash devices are use for performance (Readcache + Write buffer)
– Magnetic disks are used for storage capacity
– Disk groups cannot be createdwithout a flash device
21
disk group disk group disk group disk group disk group
Each host: 5 disk groups max. Each disk group: 1 SSD + 1 - 7 HDDs

22. Virtual SAN Datastore
• Virtual SAN is an object store solution that is presented to vSphere as
a file system
• The object store mounts the VMFS volumes from all hosts in a cluster
and presents them as a single shared datastore
– Only members of the cluster can access the Virtual SAN datastore
– Not all hosts need to contribute storage, but its recommended
22
vsanDatastore
esxi-01
disk group disk group disk group disk group
Single VSAN datastore per cluster
esxi-02 esxi-03 esxi-04

23. Virtual SAN Objects
• Virtual SAN manages data in the form of flexible data containers called
objects. Virtual machine files are referred to as objects
• Virtual machines files are referred to as objects
– There are four different types of virtual machine objects:
• VM Home
• VM swap
• VMDK
• Snapshots
• Virtual machine objects are split
into multiple components based
on performance and availability
requirements defined in
VM Storage profile
23
vsanDatastore

24. Virtual SAN Components
• Virtual SAN components are chunks of objects distributed across
multiple hosts in a cluster in order to tolerate simultaneousfailures and
meet performance requirements
• Virtual SAN utilizes a Distributed RAID architecture to distribute data
across the cluster
• Components are distributed
with the use of two main techniques:
– Striping (RAID-0)
– Mirroring (RAID-1)
• Number of component replicas and
copies created is based on
the object policy definition
24
raid-1
Mirror Copy Mirror Copy
ESXi Host ESXi Host
stripe-1b
stripe-1a
stripe-2b
stripe-2a
raid-0raid-0

25. Virtual SAN Network
• New Virtual SAN traffic VMkernel interface
– Dedicatedfor Virtual SAN intra-cluster communication and data replication
• Supports both Standard and Distributed vSwitch
– Leverage NIOC for QoS in shared scenarios
• NIC teaming – used for availability and not for bandwidth aggregation
• Layer 2 Multicast must be enabled on physical switches
– Much easier to manage and implement than Layer 3 Multicast
25
Management Virtual Machines vMotion Virtual SAN
Distributed Switch
20 shares 30 shares 50 shares 100 shares
vmnic0 vmnic1
vmk1 vmk2vmk0

26. VMware Virtual SAN
Configuration Walkthrough

27. Configure Network
27
• Configure the new dedicated Virtual SAN network
– vSphere WebClient network template configuration feature.

28. Enable Virtual SAN
• One click configuration
– Virtual SAN configured in Automaticmode, all empty local disks are
claimed by Virtual SAN for the creationof the distributed vsanDatastore
– Virtual SAN configured in Manual mode, the administrator must manually
select disks to add the the distributed vsanDatastore by creating Disk
Groups
28

29. Disk Management
• Each host in the cluster creates a single or multiple disk groups which
contain a combination of HDDs, and SSDs
29

30. Virtual SAN Datastore
• A single Virtual SAN Datastore is created and mounted, using storage
from all multiple hosts and disk groups in the cluster
• Virtual SAN Datastore is automatically presented to all hosts in the
cluster
• Virtual SAN Datastore enforces thin-provisioning storage allocation by
default
30

31. Virtual SAN Capabilities
• Virtual SAN currently surfaces five unique storage capabilities to vCenter
31

32. Number of Failures to Tolerate
• Number of failures to tolerate
– Defines the number of hosts, disk or network failures a storage object can
tolerate. For “n” failures tolerated, “n+1” copies of the object are created
and “2n+1” host contributing storage are required
32
vsan network
vmdkvmdk witness
esxi-01 esxi-02 esxi-03 esxi-04
~50% of I/O ~50% of I/O
Virtual SAN Policy: “Number of failures to tolerate = 1”
raid-1

33. Number of Disk Stripes Per Object
• Number of disk stripes per object
– The number of HDDs across which each replica of a storage object is
distributed. Higher values may result in better performance.
33
vsan network
stripe-2b witness
esxi-01 esxi-02 esxi-03 esxi-04
stripe-1b
stripe-1a stripe-2a
raid-0raid-0
VSAN Policy: “Number of failures to tolerate = 1” + “Stripe Width =2”
raid-1

34. Virtual SAN Storage Capabilities
• Force provisioning
– if yes, the object will be provisioned even is the policy specifiedin the
storage policy is not satisfiable with the resources currently available.
• Flash read cache reservation (%)
– Flash capacity reservedas read cache for the storage object. Specified as a
percentage of logical size of the object.
• Object space reservation (%)
– Percentage of the logical size of the storage object that will be reserved
(thick provisioned) upon VM provisioning. The rest of the storage object is
thin provisioned.
34

35. Virtual SAN I/O flow – Write Acknowledgement
vsan network
vmdkvmdk
esxi-01 esxi-02 esxi-03 esxi-04
VSAN mirrors write IOs to all active mirrors,
these are acknowledged when they hit the flash buffer!
witness
Destaging to HDD is done
independentlybetween hosts.
raid-1

36. VSAN IO flow – Reads
vsan network
witness
esxi-01 esxi-02 esxi-03
Read Cache
Write Buffer
Magnetic Disks
Read Cache
Write Buffer
Magnetic Disks
VSAN track of where IO resides and reads from where located
Read block 1 and 2.
Block 1 is owned by
esxi-01 and block 2
by esxi-03.
vmdk vmdk
1MB(1)
1MB(2)

37. VMware Virtual SAN
Virtual Machine Provisioning Operations

38. Virtual Machine Provisioning Operations
• All VM provisioning operation include access to VM Storage Policies
38

39. Virtual Machine Provisioning Operations
• If the Virtual SAN Datastore understands the capabilities in the VM
Storage Policy, it will be displayed as a matching resource
39

40. Virtual Machine Provisioning Operations
– If the VSAN Datastore can satisfy the
VM Storage Policy, the VM Summary
tab will display the VM as compliant
– If not, due to failures, or the force
provisioning capability, the VM will be
shown as non-compliant
40

41. Virtual Machine Policy Management
• Modify VM performance, capacity, and availability requirements without
downtime
41

42. Maintenance Mode – planned downtime
 3 Maintenance mode
options:
 Ensure accessibility
 Full data migration
 No data migration

43. VMware Virtual SAN
Summarizing

44. 44
 Installs in two clicks
 Managed from vSphere
Client
 Policy-based management
 Self-tuning and elastic
 Deep integration with
VMware stack
Radically Simple
 Embedded in vSphere
kernel
 Flash-accelerated
 Matches the VDI density of
all flash array
 Best price/performance
 100 kazillion IOps
High Performance Lower TCO
 Eliminates large upfront
investments (CAPEX)
 Grow-as-you-go (OPEX)
 Flexible choice of industry
standard hardware
 Does not require
specialized skills
Virtual SAN Key Benefits

45. Don’t forget… ;-)
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