Virtual machines might experience slow performance due to high input/output processing

Products

• VMware vSphere ESXi

Issue/Introduction

Due to high input/output processing, virtual machines might experience slow performance when you deploy the VMs on an ESXi host with write cache disabled local storage. This issue is more noticeable on an ESXi host with a host bus adapter (HBA) that does not support less than 2 ms of timeout value for I/O and experiences SCSI reservation conflicts.

Environment

VMware vSphere ESXi 6.0

Resolution

To workaround the specific errors experienced due to VMFS Reservation timeouts and aborted commands, increase the VMFS Reservation timeout from 1 second to 5 seconds using the commands:

• esxcfg-advcfg -s 5000 /VMFS3/OptLockReadTimeout
• esxcfg-advcfg -s 5000 /VMFS3/OptLockWriteTimeout

To improve the performance of the VMs, use the VMware Paravirtual SCSI adapter instead of the LSI Logic adapter.

You can find more information on how you can avoid the slow performance of the VMs from the following:

• Enabling Write Cache: KB 1002282
   
• Enabling Read/Write caching: Storage Array Performance
   
• Ensuring write-back cache is enabled: KB 1006602

Additional Information

For translated versions of this article, see:

• 日本語: 高速の入出力処理が原因で、仮想マシンのパフォーマンスが低下する可能性がある (2134536)
• 简体中文: 虚拟机的性能可能会因输入/输出处理速度较高而变缓 (2134944)
• Deutsch: Leistungsbeeinträchtigung bei virtuellen Maschinen aufgrund hoher E/A-Verarbeitung (2144675)