Hello Based on your description, it does not sound like you are using an H330 HBA. If you have RAID 1 and RAID 5 virtual disks created on the H330 then it is the H330 RAID controller. We have an article about performance expectations on controllers without cache, especially when using parity. 20MB/s sustained writes with RAID 5, SATA spindle drives, and a controller without cache does not sound abnormal to me. The performance impact of the RAID 5 will be felt on the RAID 1 with SSDs because the controller has to pause all I/O to perform parity calculations once the queue is full. [URL] If you go to the R540 support page and select ESXi 6.5 in the OS drop-down there is a category called Enterprise Solutions. That has the custom images we provide. The important information section lists all of the VIBs that we change in the image. The VIB listed there is the one validated for the PERC in that OS version. [URL] Thanks
On a new install of ESXi 6.5 on a new PowerEdge R540 using an H330 HBA, sustained write speeds to an SSD volume in RAID 1 and a SATA volume in RAID 5 are approximately 20 MB/sec.  Symptoms are very similar to those described in this post:  [URL]  Unfortunately, the only driver available is a native lsi_mr3.  After disabling that driver using the ESXi shell, the volumes connected to the H330 are no longer shown.  I tried re-enabling the driver, but each time I reboot the driver is disabled, so the volumes are lost.  But that is a problem for another day.  The big question is: What other options are available to improve performance under ESXi 6.5 to SSD and SATA volumes connected via the H330? Is there a vmklinux driver that could be substituted in place of the native driver?
Poor Write Performance using Dell R540 with H330 ESXi 6.5