VSAN poor performance

Hi All,

I have a query on new VSAN setup. Please help if you have time and any idea.

Testing Setup.
Three node VSAN AF cluster.

Dell R630 Intel(R) Xeon(R) CPU E5-2699 v3 @ 2.30GHz
512 GB of Physical RAM
HBA mini 330 [ VSAN Compatible Firmware is, Driver is default driver from ESXi OS]

Dell customized 6.7 U3 OS is using “6.7.0 Update 3 Build-17700523 (A11)

Crucial SSD disks Model “CT2000BX500SSD1, 1.82 TB disks”
Each disk group has 2*2 TB SSD (Per server)
1 * 1.82 TB Cache
1 * 1.82 TB Capacity
Broadcom 5700 10 NICS for VSAN. “BRCM 10G/GbE 2+2P 57800 rNDC”

I created a test windows 2019 VM but the performance is very poor.
While checking from ATTO/Crystal benchmark, it's writing with 20 mb (4 k block).

I created a new RAID0 policy from VSAN and tested it with above VM but the performance is very low.

Any ideas to fix this?

Thank you,

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1 Reply
VMware Employee
VMware Employee

@ManivelR , Here you are using really cheap consumer-grade SSDs (the reviews of which appear negative) that aren't supported for vSAN and are using them for both Cache and Capacity-tier and in the absolute minimum configuration (Disk-Groups comprised of single Capacity-tier absolutely not advised, nor is single Disk-Group per node).

If this is a homelab/testing station then better off using something not on HCL that can actually move (e.g. a 500GB 970 EVO as cache and multiple Capacity-tier drives), if this is intended to be a Production cluster then you need to get drives that are on the vSAN HCL and supported/rated for their intended purpose (e.g. All-Flash Cache-Tier/Capacity-tier).

You are also testing this with performance monitoring tools that have no clue what HCI is and are not going to be informative of what a Disk-Group/node/cluster can pull - use HCIBench.

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