Dell PowerStore 5200T EMC PowerStore Host Configuration Guide - Page 39

Setting the Maximum I/O, Confirming UNMAP Priority

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Query for VAAI status: # esxcli system settings advanced list --option=/DataMover/HardwareAcceleratedInit # esxcli system settings advanced list --option=/DataMover/HardwareAcceleratedMove # esxcli system settings advanced list --option=/VMFS3/HardwareAcceleratedLocking Verify the Int Value equals 1 (enabled). Enable each of the settings: # esxcli system settings advanced set --int-value 1 --option /DataMover/ HardwareAcceleratedInit # esxcli system settings advanced set --int-value 1 --option /DataMover/ HardwareAcceleratedMove # esxcli system settings advanced set --int-value 1 --option /VMFS3/ HardwareAcceleratedLocking NOTE: These settings enable ATS-only on supported VMFS Datastores, as noted in VMware Knowledge Article 1021976 (Frequently Asked Questions...). Setting the Maximum I/O Follow these guidelines to set the maximum I/O request size for storage devices. Disk.DiskMaxIOSize determines the maximum I/O request size that is passed to storage devices. With PowerStore and ESXi release earlier than 7.x, it is required to change this parameter from 32767 (the default setting of 32 MB) to 1024 (1 MB). Example: Setting Disk.DiskMaxIOSize to 1024 (1 MB). esxcli system settings advanced set -o "/Disk/DiskMaxIOSize" --int-value 1024 NOTE: When setting Disk.DiskMaxIOSize to 1 MB on ESXi hosts connected to arrays other than PowerStore, performance on large I/Os may be impacted. NOTE: Setting the maximum I/O size is only required for ESXi versions earlier than 7.0, unless the ESXi version used is not exposed to the issue covered in VMware Knowledge Article 2137402 (Virtual machines using EFI firmware...). Confirming UNMAP Priority This topic provides steps for setting UNMAP priority on a DataStore. Prerequisites NOTE: Provisioning Virtual Disks with UNMAP set to a non-default priority on a DataStore provisioned on PowerStore may result in an increased amount of write I/Os to the storage subsystem. It is therefore highly recommended to verify that UNMAP is set to Low priority. NOTE: See Dell EMC Knowledge Article 000126731 (Best practices for VMFS datastores...) for further unmap-related recommendations when doing Virtual Machine File System (VMFS) bootstorm or failover with VMware Site Recovery Manager (SRM) on VMFS datastores from ESXi hosts connected to PowerStore. To set UNMAP priority on a datastore: Steps 1. On most ESXi hosts, the default UNMAP priority is set to Low. It is recommended to verify, using ESX CLI, that the datastores are configured with Low priority. 2. To verify that a datastore is set to Low priority: a. List the file systems: [~] esxcli storage filesystem list Mount Point Volume Name Host Configuration for VMware vSphere ESXi 39

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Query for VAAI status:
# esxcli system settings advanced list --option=/DataMover/HardwareAcceleratedInit
# esxcli system settings advanced list --option=/DataMover/HardwareAcceleratedMove
# esxcli system settings advanced list --option=/VMFS3/HardwareAcceleratedLocking
Verify the
Int Value
equals 1 (enabled).
Enable each of the settings:
# esxcli system settings advanced set --int-value 1 --option /DataMover/
HardwareAcceleratedInit
# esxcli system settings advanced set --int-value 1 --option /DataMover/
HardwareAcceleratedMove
# esxcli system settings advanced set --int-value 1 --option /VMFS3/
HardwareAcceleratedLocking
NOTE:
These settings enable ATS-only on supported VMFS Datastores, as noted in
VMware Knowledge Article 1021976
(Frequently Asked Questions...)
.
Setting the Maximum I/O
Follow these guidelines to set the maximum I/O request size for storage devices.
Disk.DiskMaxIOSize
determines the maximum I/O request size that is passed to storage devices. With PowerStore and
ESXi release earlier than 7.x, it is required to change this parameter from 32767 (the default setting of 32 MB) to 1024 (1 MB).
Example: Setting Disk.DiskMaxIOSize to 1024 (1 MB).
esxcli system settings advanced set -o "/Disk/DiskMaxIOSize" --int-value 1024
NOTE:
When setting Disk.DiskMaxIOSize to 1 MB on ESXi hosts connected to arrays other than PowerStore, performance
on large I/Os may be impacted.
NOTE:
Setting the maximum I/O size is only required for ESXi versions earlier than 7.0, unless the ESXi version used is not
exposed to the issue covered in
VMware Knowledge Article 2137402 (Virtual machines using EFI firmware...)
.
Confirming UNMAP Priority
This topic provides steps for setting UNMAP priority on a DataStore.
Prerequisites
NOTE:
Provisioning Virtual Disks with UNMAP set to a non-default priority on a DataStore provisioned on PowerStore may
result in an increased amount of write I/Os to the storage subsystem. It is therefore highly recommended to verify that
UNMAP is set to Low priority.
NOTE:
See
Dell EMC Knowledge Article 000126731 (Best practices for VMFS datastores...)
for further unmap-related
recommendations when doing Virtual Machine File System (VMFS) bootstorm or failover with VMware Site Recovery
Manager (SRM) on VMFS datastores from ESXi hosts connected to PowerStore.
To set UNMAP priority on a datastore:
Steps
1.
On most ESXi hosts, the default UNMAP priority is set to Low. It is recommended to verify, using ESX CLI, that the
datastores are configured with Low priority.
2.
To verify that a datastore is set to Low priority:
a.
List the file systems:
[~] esxcli storage filesystem list
Mount Point
Volume Name
Host Configuration for VMware vSphere ESXi
39