I have R620 server. I have that disks:

  • 4x512GB Samsung SSD
  • 4x1TB Seagate ES.2 HDD

I will use Vmware Esxi to create virtual machines. What's the best option? Using SSD's as primary drives and use them at RAID10 or using HDD's with RAID10?

I will host 1200 websites on this server with cPanel.

Capacity is not my concern. But performance is. When I Raid 10 with SSD's, it doesn't really show 4x performance and 4K Seq. Read/Write rate is very low. So that makes me think using it.

  • Possible duplicate of Can you help me with my capacity planning?
    – user143703
    Apr 20, 2017 at 18:42
  • RAID10 is your best option for performance, with a reasonable level of availability. Your other option would be RAID5 (but only for the SSDs) for storage at the cost of performance. Are you using hardware or software raid? What model are the Samsung SSDs and what is the actual IO you are seeing when benchmarking? Apr 20, 2017 at 20:33
  • I'm using Samsung 850 PRO SSD's. When I raid 10 with them read speed is 3x, write speed is 2x, 4k seq. read and write speed is same as 1 drive. Nothing changes on 4k seq. side.
    – Murat G
    Apr 21, 2017 at 5:47

1 Answer 1


Check the RAID configuration you have. In order to obtain the max performance of RAID. It is recommended to configure stripe size value of 64k for both HDDs and SSDs. Also, check disk cache. For HDD set cache to default, read ahead and write-trough, while for SSDs it should be default, no read ahead and write-back.

Check the RAID documentation, to familiralize yourself with Impact of RAID Settings on Performance. Source: http://download.intel.com/support/motherboards/server/sb/configuring_raid_for_optimal_perfromance_11.pdf

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