sadom
Enthusiast
Enthusiast

vsan physical server

I'm doing some research to learn vsan. I did not understand some topics. I guess I should buy a compatible server for vsan. I have a scenario in my mind, for example, if I buy at least 3 vsan compatible physical servers. If I buy 2 x250 GB SATA disks for ESXi installation and 10x250 GB SSD disks on each of these servers for vsan. how do i install it?

I'm doing 2x250 GB SATA disk raid 1 and installing esxi on these disks. So, do I need to create any raid structure for 10X250 GB SSD disks before installing vsan?

I could not understand whether to make a raid group for 10x250 gb ssd disks.

 

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10 Replies
IRIX201110141
Champion
Champion

I highly suggest so buy vSAN Ready Nodes from your favorite Vendor.

Some of your questions are answered here https://communities.vmware.com/t5/VMware-vSAN-Discussions/vsan-7-install/m-p/2881426#M13673

 

HPE and DellEMC offer RAID1 like cards with 2x M.2 240 SSDs for the ESXi.  A "special" passtrough only HBA is needed for all vSAN disks which means no RAID, Battery, Cache or what ever!

A single vSAN Host contains at least one Diskgroup which contains up to 1 + 7 Disks.
Hybrid Config: 1x Cache(rd/wr) SSD + up to 7 Magnetic spindles as capacity drives( Hybrids are not very command these days!)
AllFlash: 1x Buffer SSD (wr only) + up to 7 SSD for the capacity

A vSAN Host can have up to 5 Disk groups. Most of my setups have 2 Diskgroups per Hosts and every DG contains between 3-5 capacity disks.

The vSAN will created after you setup and installed your 3 or more ESXi Hosts, vCenter and Cluster configuration. This is the different compared to a classic external storage array.

Regards,
Joerg

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bryanvaneeden
Hot Shot
Hot Shot

Hi @sadom ,

I think @IRIX201110141 already answered some of your questions. I want to add to that list that you can use Raid 1 for the 2x250GB ESXi boot disks for sure.

For the vSAN Capacity/Cache disks you do not need to use a passthrough-only HBA, you can also use RAID 0 for each disk. This does mean you have to create a RAID 0 per physical disk if you are not using passthrough. Please have a look at the official documentation: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.vsan-planning.doc/GUID-475FAD6E-2A1... 

I've had both on my environments, both work fine. But passthrough is obviously easier to configure and keep.

I hope this works for you!

Visit my blog at https://vcloudvision.com!
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IRIX201110141
Champion
Champion

This RAID0 for every single Disk is just a simple Workaround from the time where these Passtrough Only HBAs not exsists or people have already invest into a full blown featurerich RAID HBA. Current HighEnd HBA can switch between RAID and Passtrough mode depends on what you need.

If you buy today something new go for the way cheaper passtrough HBA* which saves you some $$$ and in the end you get more features from the vSAN perspective because vSAN would like to use with s.m.a.r.t and and checking FW of the drives and more.

DellEMC 14Gen. = HBA330
DellEMC 15Gen. = HBA355i

HPE and Leveno will have these to (other names of course).  You can download the xxx pages long VMware vSAN ReadyNode model catalog which contains all existing vendors and there offerings and lurking what kind of hardware they use.

Regards,
Joerg

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bryanvaneeden
Hot Shot
Hot Shot

Agreed, if you go new, you can buy the passthrough only HBA's if you need to save some $$$. But you can do it with RAID 0 configurations for sure.

Visit my blog at https://vcloudvision.com!
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IRIX201110141
Champion
Champion

Yes.
Our oldest vSAN also use RAID0 on the Dell PERC H730(p). It runs 🙂

Regards,
Joerg

 

 

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sadom
Enthusiast
Enthusiast

I don't fully understand the Raid 0 thing. I used it for 2x265gb esxi. Will the remaining 2x250 ssd be raid 0 on 10 disks? This question will be done on the configuration ilo or idrac.

i can't understand it. Why do we configure raid on 10 ssd disks? If I install vcenter without any configuration and activate vsan and merge all the disks from there, won't it work?

Let me ask, I bought a new server, then I installed esxi on 2x2560 gb disks. the remaining 10x256 gb ssd disk is idle, I did not take any action. ( no raid config - I didn't do anything ) then I installed vcenter and enabled vsan. Isn't that the setup?

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IRIX201110141
Champion
Champion

For me it looks like you havent get the basic rules of VMwares vSAN implementation

  1. a vSAN cluster needs 3 or more phys. Hosts. There is a special option for 2 Host and a virtual one as the 3rd.
  2. vSAN needs to see every single disk on it own within the Host. What ever it take to configure on your current HBA you have to do it pririor to match this requirement
  3. a vSAN Diskgroup contains at least one special device for Caching and one for Capacity

 

Regards
Joerg

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bryanvaneeden
Hot Shot
Hot Shot

The RAID on the remaining 10 disks is only needed if the HBA doesn't support passthrough of the disks. It's either one or the other for vSAN. Doesn't matter which one you choose (ofcourse as long they are on the vSAN HCL).

And like @IRIX201110141 said, you do need 3 hosts minimum to create a vSAN cluster.

Visit my blog at https://vcloudvision.com!
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TheBobkin
VMware Employee
VMware Employee

@bryanvaneeden "Doesn't matter which one you choose." Sorry but I have to indicate that this is not the case - some controllers are tested and certified on the vSAN HCL by hardware vendors for passthrough and (not many these days) as RAID0 access mode - if one decides to ignore what has been tested and certified and use the opposite then they are taking it upon themselves to support it (as the hardware vendor nor VMware have given any indication of what is configured is expected to work) and this is not advisable.

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bryanvaneeden
Hot Shot
Hot Shot

@TheBobkin 

Sorry you are true. I edited my post, I forgot to mention that ofcourse it should be supported and on the HCL in the first place, I figured we knew that. But when choosing hardware once the first is done it doesn't really matter anymore in regards to the controller.

Visit my blog at https://vcloudvision.com!
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