VMware - iSCSI / Fiber Channel Best Practices

 

Multipathing

A) Increase max bandwidth by adding additional paths (iSCSI only)

In order to achieve maximum throughput Zadara recommends creating a minimum of 4 paths to each iSCSI device (8 optimal).  See the following guide for additional information

https://support.zadarastorage.com/hc/en-us/articles/360000502523-VMware-Increase-iSCSI-Bandwidth-by-Adding-Additional-Paths 

**note: We have observed that adding additional paths will not provide meaningful performance benefits unless the Round Robin IOPS limit is set to 1 (see below) 

B) Path Selection Policy = Round Robin

For best performance Zadara recommends to use the Round Robin path selection policy.  With Round Robin the host uses an automatic path selection algorithm rotating through all active paths, instead of a fixed or most recently used path.

Path selection policies are configured on a per-device basis in VMWare. 

**note: We have observed that setting the path selection policy to Round Robin will not provide meaningful performance benefits unless the Round Robin IOPS limit is set to 1 (see below) 

C) Round Robin IOPS Limit = 1

When using the Round Robin Path Selection Policy it is critical, for performance reasons, to change the Round Robin IOPS limit to 1 (default is 1000).  This setting will determine the number of IOPS VMWare will issue before switching to the next available path.

https://support.zadarastorage.com/hc/en-us/articles/360000501266-VMware-Set-Round-Robin-IOPS-Limit-for-all-Zadara-Devices 

  

iSCSI Initiator Settings

Zadara Storage recommends that this and that be set according to https://support.zadarastorage.com/hc/en-us/articles/115003993126-VMware-ESXi-Initiator-iSCSI-settings 

 

 

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