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This is a presentation on storage-related changes in VMware vSphere 4.1. I gave this presentation at the Triad VMUG meeting in Greensboro, NC on January 28, 2011.
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1© Copyright 2010 EMC Corporation. All rights reserved.
Storage Changes in VMware vSphere 4.1A quick review of changes and new features
Scott Lowe, VCDX 39vSpecialist, EMC CorporationAuthor, Mastering VMware vSphere 4Blogger, http://blog.scottlowe.org
2© Copyright 2010 EMC Corporation. All rights reserved.
Storage Feature Summary• 8 Gbps FC HBA and expanded support for
FCoE CNAs
• New storage performance statistics
• Storage I/O Control
• vStorage APIs for Array Integration
• iSCSI enhancements
3© Copyright 2010 EMC Corporation. All rights reserved.
New Storage Performance Statistics• More comprehensive performance statistics
available both in vCenter and esxtop/resxtop– Historical/real-time via GUI in vCEnter– Real-time via esxtop/resxtop for
drill-down/scripting
• Latency and throughput statistics available for:
– Datastore per host– Storage adapter and path per host– Datastore per VM– VMDK per VM
• Greater feature parity across all storage protocols
4© Copyright 2010 EMC Corporation. All rights reserved.
Storage I/O Control
5© Copyright 2010 EMC Corporation. All rights reserved.
The I/O Sharing Problem
What You See Now What You Should See
datastore
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MicrosoftExchange
datastore
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MicrosoftExchange
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Solution: Storage I/O Control (SIOC)
32GHz 16GB
Datastore A
CPU shares: High
Memory shares: Highonline store
MicrosoftExchange
data mining
CPU shares: Low
Memory shares: Low
CPU shares: High
Memory shares: High
I/O shares: High I/O shares: LowI/O shares: High
7© Copyright 2010 EMC Corporation. All rights reserved.
Setting I/O Controls
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Enabling Storage I/O Control
Storage I/O Control Enabled
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Viewing Configuration Settings
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Allocate I/O Resources• Shares translate into ESX I/O queue slots
– VMs with more shares are allowed to send more I/O’s at a time
– Slot assignment is dynamic, based on VM shares and current load
– Total # of slots available is dynamic, based on level of congestion
I/O’s in flight
STORAGE ARRAY
data mining
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Congestion Triggers SIOC• Congestion signal: ESX-array response time
> threshold– Default threshold: 30ms– Should set different defaults for SSD and SATA
• Changing default threshold (not usually recommended)
– Low latency goal: set lower if latency is critical for some VMs
– High throughput goal: set close to IOPS maximization point
12© Copyright 2010 EMC Corporation. All rights reserved.
vStorage APIs for Array Integration
13© Copyright 2010 EMC Corporation. All rights reserved.
Storage Integration Points
FC/FCoE & iSCSIArray APIs/Mgmt
vCenter
VAAI SCSI cmds
ESX Storage Stack
Datamover
Vendor-specific Plug-Ine.g. EMC Virtual Storage
Integrator
View VMware-to-Storage relationshipsProvision datastores more easily
Leverage array features (compress/dedupe, file/filesystem/LUN
snapshots
VI Client VM
Storage Array
VMFS NFS
NFSclient
Network Stack
VMware LVM
HBA Drivers
VSS via VMware Tools Snap request
SvMotion requestVM provisioning cmdTurn thin prov on/off
Vendor-specific VAAI SCSI command support
vStorage API for Multi-
pathing
NMP
Future NFS offloads
NFS
NIC Drivers
vStorage API for Data Protection
(VDDK)
Vendor Specific
vStorage API for SRM
SRM
VM-Aware Unisphere
Co-op
Co-
op
14© Copyright 2010 EMC Corporation. All rights reserved.
Current VAAI Primitives• Hardware-Accelerated Locking = 10-100x better metadata
scaling– Replace LUN locking with extent-based locks for better
granularity– Reduce number of “lock” operations required by using one
efficient SCSI command to perform pre-lock, lock, and post-lock operations
– Increases locking efficiency by an order of magnitude
• Hardware-Accelerated Zero = 2-10x lower number of IO operations
– Eliminate redundant and repetitive host-based write commands with optimized internal array commands
• Hardware-Accelerated Copy = 2-10x better data movement– Leverage native array Copy capability to move blocks
15© Copyright 2010 EMC Corporation. All rights reserved.
Hardware-Accelerated Locking• Without API
– Reserves the complete LUN so that it could obtain a lock
– Required several SCSI commands– LUN level locks affect adjacent hosts
• With API– Locks occur at a block level
One efficient SCSI command - SCSI Compare and Swap (CAS)
– Block level locks have no effect on adjacent hosts.
• Use Cases– Bigger clusters with more VMs– View, Lab Manager, Project Redwood– More & Faster VM Snapshotting
16© Copyright 2010 EMC Corporation. All rights reserved.
Parameter for Hardware-Accelerated Locking
Q: Can this be changed without a reboot?
A: Yes!
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Hardware-Accelerated Zero• Without API
– SCSI Write - Many identical small blocks of zeroes moved from host to array for MANY VMware IO operations
– Extra zeros can be removed by EMC arrays after the fact by “zero reclaim”
– New Guest IO to VMDK is “pre-zeroed”
• With API– SCSI Write Same - One giant block of
zeroes moved from host to array and repeatedly written
– Thin provisioned array skips zero completely (pre “zero reclaim”)
• Use Cases– Reduced IO when writing to new blocks in
the VMDK for any VM– Time to create VMs (particularly FT-enabled
VMs
VMDK
SCSI WRITE (0000…..)SCSI WRITE (data)SCSI WRITE (0000….)SCSI WRITE (data)Repeat MANY times…
SCSI WRITE SAME (0 * times)SCSI WRITE (data)
18© Copyright 2010 EMC Corporation. All rights reserved.
Parameter for Hardware-Accelerated Zero
Q: Can this be
changed without a reboot?
A: Yes!
19© Copyright 2010 EMC Corporation. All rights reserved.
Hardware-Accelerated Copy• Without API
– SCSI Read (Data moved from array to host)– SCSI Write (Data moved from host to array)– Repeat– Huge periods of large VMFS level IO, done via
millions of small block operations
• With API– SCSI Extended Copy (Data moved within array)– Repeat– Order of magnitude reduction in IO operations– Order of magnitude reduction in array IOps
• Use Cases– Storage VMotion– VM Creation from Template
SCSI READSCSI READSCSI READ..MANY times…
SCSI EXTENDED COPY
SCSI WRITESCSI WRITESCSI WRITE..MANY times…
“let’s Storage VMotion”“let’s Storage VMotion”
“Give me a VM clone/deploy from template”
20© Copyright 2010 EMC Corporation. All rights reserved.
Parameter for Hardware-Accelerated Copy
Q: Can this be changed without a reboot?
A: Yes!
21© Copyright 2010 EMC Corporation. All rights reserved.
iSCSI Enhancements
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iSCSI Enhancements in vSphere 4.1• Boot from software iSCSI (iBFT)
• iSCSI offloading
• iSCSI session management
• Additions have also been made to the CLI
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Steps in Booting from Software iSCSI• Ensure that the NIC you wish to use supports iSCSI
Boot.
• Ensure that the NIC has a supported version of firmware.
• Ensure that iSCSI Boot option is selected in the host BIOS for the NIC.
• Configure the iSCSI Boot parameters in the NIC BIOS.
• Configure the iSCSI target to allow initiator (NIC) access.
• Configure a LUN on the iSCSI target and present to the initiator.
24© Copyright 2010 EMC Corporation. All rights reserved.
Q&A
25© Copyright 2010 EMC Corporation. All rights reserved.
THANK YOU