VMware vSphere 4 Guida Utente Pagina 5
- Pagina / 71
- Indice
- SEGNALIBRI
Valutato. / 5. Basato su recensioni clienti
Technical white paper | HP Enterprise Virtual Array Storage and VMware vSphere 4.x and 5.x configuration best practices
5
ALUA compliance
All EVA storage solutions – models P6x00, EVA8x00/6x00/4x00 – are dual-controller asymmetric active-active arrays that
are compliant with the SCSI ALUA standard for Vdisk access/failover and I/O processing.
Note
ALUA is part of the SCSI Primary Commands – 3 (SPC-3) standard.
While the active-active nature of the array allows I/O requests to a Vdisk to be serviced by either controller, the array’s
asymmetry forces the optimal access path to the Vdisk to be used (that is, the I/O path to the controller that requires less
processing overhead).
The controller with the optimal path to the Vdisk – managing controller – can issue I/Os directly to the Vdisk, whereas the
non-managing controller – proxy controller – can receive I/O requests but must pass them to the managing controller to
initiate fulfillment.
The following example shows how a read I/O request sent to the non-managing controller is processed:
1. The non-managing controller transfers the request (proxy) to the managing controller for the Vdisk.
2. The managing controller issues the I/O request to the Vdisk and caches the resulting data.
3. The managing controller then transfers the data to the non-managing controller, allowing the request to be fulfilled via
the controller/server ports through which the server initiated the request.
Thus, a proxy read – a read through the non-managing controller – generates processing overhead.
Note
Since write requests are automatically mirrored to both controllers’ caches for enhanced fault tolerance, they are not
affected by proxy processing overhead. Thus, the managing controller always has a copy of the write request in its local
cache and can process the request without the need for a proxy from the non-managing controller.
Vdisk controller ownership and access
The ability to identify and alter Vdisk controller ownership is defined by the ALUA standard.
EVA arrays support the following ALUA modes:
• Implicit ALUA mode (implicit transition) – The array can assign and change the managing controller for the Vdisk
• Explicit ALUA mode (explicit transition) – A host driver can set or change the managing controller for the Vdisk
EVA arrays also support the following ALUA access types:
• Active-Optimized (AO) – The path to the Vdisk is through the managing controller
• Active-Non-Optimized (ANO) – The path to the Vdisk is through the non-managing controller
ALUA compliance in vSphere 4.x and 5.x
ALUA compliance was one of the major features added to the vSphere 4 SCSI architecture and remains standard in vSphere
4.1 and 5.x. The hypervisor can detect whether a storage system is ALUA-capable; if so, the hypervisor can optimize I/O
processing and detect Vdisk failover between controllers.
vSphere 4.x and 5.x support all four ALUA modes:
• Not supported
• Implicit transitions
• Explicit transitions
• Both implicit and explicit transitions
In addition, vSphere 4.x supports all five ALUA access types:
• AO
• ANO
- HP Enterprise Virtual Array 1
- Storage and VMware vSphere 1
- Executive summary 4
- The challenges 4
- Key concepts and features 4
- ALUA compliance 5
- Configuring EVA arrays 6
- Using Command View EVA 7
- Disk group provisioning 13
- Vdisk provisioning 16
- • EVA Controllers 18
- Controller connections 20
- Front-end GbE and FC ports 20
- • Fixed_AP 24
- • Round robin 24
- • Fixed 24
- • Configure the Vdisk 25
- Configuring multi-pathing 27
- • SATP 28
- Displaying the SATP list 29
- Disk Group 33
- DR Group 33
- Upgrading EVA microcode 34
- Using VMFS 35
- Using RDM 35
- Comparing supported features 36
- Sizing the vSphere cluster 38
- Aligning partitions 38
- Optimizing queue depth 39
- Using adaptive queuing 39
- Optimizing I/O size 42
- • Plugin-less deployment 44
- VAAI operation concurrency 46
- ESX UNMAP support history 47
- UNMAP in ESXi 5.5 49
- Summary of best practices 51
- Summary 53
- Glossary 53
- Changing the default PSP 56
- Figure C-2. I/O routes 58
- Sample configuration 62
- Configuring the vSphere host 64
- Configuring the array 68
- Configuring the VM 69
- For more information 71
McCulloch Eager Beaver EBC1840DK Handbücher
Bedienungsanleitungen und Benutzerhandbücher für Benzinwerkzeug McCulloch Eager Beaver EBC1840DK.
Wir stellen 1 PDF-Handbücher McCulloch Eager Beaver EBC1840DK zum kostenlosen herunterladen nach Dokumenttypen zur Verfügung Bedienungsanleitung
Commenti su questo manuale