Raid 5 or 6 on esxi?

[april14507]

I happened to read somewhere saying Raid 5 or Raid 6 is not good for esxi6. The better choices are Raid 0, 1, or 10. Why? Can someone explain the reason? Thank you very much in advance!!!

[jrodsguitar]

For just esxi deploy a pair of SSD's in Raid 1. It will run well and is redundant. You'll be fine.

[golddiggie]

What's the use of the volume going to be?? That will really determine what RAID level to pick.

IME, for ESXi, go RAID 1. But, I've also been loading ESXi onto either USB flash drives (thumb drives) or dual SD card modules (mirrored) for some time now. Both in work and home lab environments.

For datastore volumes, it will depend on what kind of IOPS you need and what the drives are. Not to mention what kind of reads/write activity you'll be seeing. There are penalty calculation tools out there to help you figure that out. Depending on the use case, and drive count, RAID 10 might be good for you. Or RAID 6. Depending on how reliable the array has to be, RAID 5 might not be resilient enough (can only suffer one drive failure before you're FUBAR).

Another element will be what type of drive you'll be using. 10k spindle? 15k spindle? 2.5" or 3.5" spindle? SSD and class of SSD?

[april14507]

There will be esxi and vms running on one box which is Dell PowerEdge R440. And the equipment does have raid 5 to be configured. Is it ok for esxi host?

[golddiggie]

Provided you have a hardware RAID controller, it will work. Performance, and resiliency, though could be another matter. If the controller doesn't start with "H" then you're boned ("S" labeled controllers are software controllers and ESXi will see the drives outside of a RAID config even if you do it under the BIOS/UEFI configuration items).

[april14507]

thank you.

The specification sheet says:

Internal controllers: PERC H330, H730p, H740p, HBA330, Software RAID (SWRAID) S140

Boot Optimized Storage Subsystem: HWRAID 2 x M.2 SSDs 120GB, 240 GB

External PERC (RAID): H840

External HBAs (non-RAID): 12 Gbps SAS HBA

also the sheet says: it supports VMware ESXi. I guess that I should be ok.

Supported operating

systems

Canonical® Ubuntu® LTS

Citrix® XenServer®

Microsoft Windows Server® with Hyper-V

Red Hat® Enterprise Linux

SUSE® Linux Enterprise Server

VMware® ESXi

[golddiggie]

"Internal controllers: PERC H330, H730p, H740p, HBA330, Software RAID (SWRAID) S140"

That's just a list of what your options were at build time. Unless this is from the actual server build sheet (that comes on the side of the box).

Personally, I don't waste money on RAID controllers and SSD drives when ESXi is the ONLY thing that will be on it. I go for the ~$100 option of the dual 16GB SD card module instead. Even that is more than what's needed. I then set the syslog path to a datastore on the SAN (a dedicated LUN of about 10GB just because I'm pretty sure I'd never fill it) and call it a day. Instead of spending about a grand on the RAID controller and drives, I spend about $100. I'd rather put those savings into something like a bigger CPU set, or more RAM at purchase. Or just keep it in the budget for later in that year/quarter.

[april14507]

good idea! But that purchase has been done and is out of my control.

Thank you for your kind and detailed explanation.

A side question since you mentioned esxi installing on usb:

My plan is to use rufus to load esxi installer and make a bootable usb. When I boot the equipment from usb and install the esxi 6.7, will the installation take the whole disk space on the equipment and shall I have to partition the disk before the installation? Because the whole disk will also include for the room of the datastore and vms.

Thank you!!!

[golddiggie]

I've never used third party tools to boot ESXi from an USB thumb drive. The installer will recognize any valid/good thumb drives as a valid (selectable) destination for ESXi to live on. It will install on a portion of the device (uses less than 4GB, but I usually get a device with 16GB, or more) and leave the rest available. I don't recall if you can actually use any of the remaining space for anything though. You WILL want to put the syslogs onto a different device though. You'll have an alert post installation about the syslog not using persistent storage. That's why I've used a datastore on the SAN for this at the last work environment. I made the LUN all of 10GB (when you have 30TB+, 10GB is nothing). In my home lab, I don't recall if I put it on the internal SATA drive, or on the iSCSI LUN/datastore I use for most of my VMs (a NAS).

If the USB drive/device is NOT visible in the ESXi installer DON'T USE IT! That will mean it's NOT worth installing on (I've seen this most with PNY branded drives). SanDisk and other better brands rarely, if ever, have an issue.

I've also installed on both USB2 and USB3 thumb drives without issue. Even on hosts without USB3, the USB3 drives work just fine. Again, ESXi loads into memory. So once it's booted, and you're no longer doing anything to the USB drive, it will perform just fine.

[april14507]

thank you very much for the helpful information.