Optimize ESXi for SSD

ESXi Host Settings

Set the maximum number of consecutive “sequential” I/Os allowed from one VM before switching to another VM:

1	~ # esxcfg-advcfg -s 64 /Disk/SchedQuantum

Set the maximum I/O request size passed to storage devices. With XtremIO, it is required to change it from 32767 (default setting of 32MB) to 4096 (4MB):

1	~ # esxcfg-advcfg -s 4096 /Disk/DiskMaxIOSize

Set the maximum number of active storage commands (I/Os) allowed at any given time at the VMkernel :

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For ESXi 5.0 & 5.1 ~ # esxcfg-advcfg -s 256 /Disk/SchedNumReqOutstanding For ESXi 5.5 ~ # esxcli storage core device list | grep "Display Name: XtremIO" | awk -F'[()]' '{cmd="esxcli storage core device set -d " $2 " -O 256"; system(cmd)}'

Note : The setting for vSphere 5.5 is per volume! So after adding a volume to a ESXi 5.5 host this command needs to be rerun.

Verify which HBA module is currently loaded

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Qlogic ~ # esxcli system module list | egrep "ql|Loaded" Emulex ~ # esxcli system module list | egrep "lpfc|Loaded" Cisco UCS FNIC ~ # esxcli system module list | egrep "fnic|Loaded"

For example when using Qlogic :

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~ # esxcli system module list | egrep "ql|Loaded" Name           Is Loaded   Is Enabled qlnativefc     true        true

Set Queue Depth (in this case Qlogic)

1	~ # esxcli system module parameters set -p ql2xmaxqdepth=256 -m qlnativefc

Reboot the host and than verify that queue depth adjustment is applied

1 2	~ #  esxcli system module parameters list -m qlnativefc | grep ql2xmaxqdepth ql2xmaxqdepth   int   256    Maximum queue depth to report for target devices.

When using the vSphere Native Multipathing :

Set the vSphere NMP Round Robin path switching frequency to XtremIO volumes from the default value (1000 I/O packets) to 1:

1	~ # esxcli storage nmp satp rule add -c tpgs_off -e "XtremIO Active/Active" -M XtremApp -P VMW_PSP_RR -O iops=1 -s VMW_SATP_DEFAULT_AA -t vendor -V XtremIO

When using the EMC PowerPath software :

Upload the EMC PowerPath software installer to a local datastore and run the following line (be sure to change the path and filename to your own specifications!).

1	~ # esxcli software vib install -d /vmfs/volumes/VMFSVOLUME/EMCPower.VMWARE.5.9.SP1.P02.b054.zip

vCenter Settings

The maximum number of concurrent full cloning operations should be adjusted, based on the XtremIO cluster size. The vCenter Server parameter config.vpxd.ResourceManager.maxCostPerHostdetermines the maximum number of concurrent full clone operations allowed (the default value is 8). Adjusting the parameter should be based on the XtremIO cluster size as follows:

10TB Starter X-Brick (5TB) and a single X-Brick – 8 concurrent full clone operations

Two X-Bricks – 16 concurrent full clone operations

Four X-Bricks – 32 concurrent full clone operations

Six X-Bricks – 48 concurrent full clone operations

VAAI

Be sure to check if VAAI is enabled :

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~ # esxcfg-advcfg -s 1 /DataMover/HardwareAcceleratedMove ~ # esxcfg-advcfg -s 1 /DataMover/HardwareAcceleratedInit ~ # esxcfg-advcfg -s 1 /VMFS3/HardwareAcceleratedLocking

Why? Let me show you the differences between the deployment of a Windows 2012 R2 template (15GB) with VAAI enabled and disabled :

VAAI enabled : 34 seconds

Performance Testing

Before and after changing the settings I ran some simple IOmeter tests with the following configuration :

4x Windows 2012 R2 4vCPU’s, 8GB, 40GB vDisk for OS, 40GB vDisk connected to a Paravirtual vSCSI Adapter used for the IOmeter test file.

One of the VM’s was used as IOmeter manager / dynamo and the rest of the IOmeter dynamo processes connected to the manager, all configured with 4 workers per dynamo process. The VM’s where on the same ESXi host to be sure that we can compare the results and no other influences could affect the tests.

Default ESXi Settings

Test Name	IOPS	MBps
Max Throughput-100%Read	67604	2107
RealLife-60%Rand-65%Read	68803	528
Max Throughput-50%Read	44780	1392
Random-8k-70%Read	74179	574

Optimal ESXi Settings

Test Name	IOPS	MBps
Max Throughput-100%Read	93876	2924
RealLife-60%Rand-65%Read	108679	841
Max Throughput-50%Read	39949	1240
Random-8k-70%Read	100129	773

Not bad increase of IOPS and throughput I must say! My advice? Apply the recommended settings!