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ESX Disk Configuration

Looking for a little input on this system configuration.  I have a DELL R520 in a remote office that as setup as a physical server.  Since we don't have much access to the site and limited HW budget for that office I wanted to rebuild the machine with ESXi to give us a little more flexibility to remotely spin up servers and perform maintenance.  At present the system has 8 x 7200RPM SAS drives configured as follows:

2 Drives Raid 1 with 1 Hot Spare (2 Partitions System and Data)
4 Drives Raid 5 with 1 Hot Spare (1 Large Data Partition)

We don't need anywhere near that level of data store at this location <1TB with the obvious need for some future growth.  I was planing to do the following:

Install Dell Internal Dual SD Module (IDSDM) with cards to run ESXi, thus freeing up my hard drives to be dedicated to VM hosting.  The question is would it make more sense to:

A) 8 Drives in RAID 10

 or

B) 4 Drives Raid 10
     4 Drives Raid 10

From a performance perspective does it make any sense to create separate RAID 10 volumes?  Initially There would be a very light load File Server and a Read Only Domain controller running, but I'm looking to possibly host some redundant Web/DB servers on the box.  Again read only "reporting" DBs.  My first though was to run the DC and FS on the first volume and leave the second available for these additional system.  Possibly even putting the web boxes on VOL1 and leave VOL2 strictly for a DB.  

Am I over thinking this?  Should I just stick with a 8 drive RAID 10?
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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
Install Dell Internal Dual SD Module (IDSDM) with cards to run ESXi, thus freeing up my hard drives to be dedicated to VM hosting.  

This is good, and an excellent idea, make sure you update the firmware on the server, using the latest available from Dell, and also download and use the OEM ESXi version from Dell Website, most forget this step!

Check your server is on the HCL.

Check the VMware Hardware Compatability Lists HCL here

The VMware Hardware Compatibility List is the detailed lists showing actual vendor devices that are either physically tested or are similar to the devices tested by VMware or VMware partners. Items on the list are tested with VMware products and are known to operate correctly.Devices which are not on the list may function, but will not be supported by VMware.

http://www.vmware.com/go/hcl

If you want the best performance possible, RAID 10, with all the disks, will be the fastest.

more disks = more spindles = more performance = more IOPS.

or you could do RAID 6 with Hot Spares, or RAID 10 with Hot Spares.

you can then "carve" out virtual disks (LUNs), to present to ESXi, to keep them small.

Author

Commented:
Would carving out 2 seperate LUNs from a single 8 Disk RAID 10 offer any protection from say an IOPS heavy DB impacting performance of the other systems?  Or since this is a logical and not physical separation, ie. shared spindles, there would be potential issues?
VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017
Commented:
All the IOPS are going to hit the same controller, and they will be spread over the entire 8 disks.

as opposed to 4 disks. So you will get better performance.

What you are doing is splitting the LUNs, so you do not have a massive single datastore, which if it gets corrupted you will lose all your VMs, so it's protection.

We do the same with a SAN, Array is across all the spindles, but then we carve our virtual storage (LUNs) from all the spindles and present to the ESXi host.

"Too many eggs in one basket".

Author

Commented:
Excellent description, much appreciated.
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
no problems...