Storage clustered

[Dario19]

Hello,

I'm new in Vmware world and I'm a bit confused.

This would be the result I want to achieve:

2 Hosts clustered / 10/15 VMs stored in 2 clustered datastore (NAS)

First of all, does it make sense or is there a better way to obtain HA?

Is it possible with Essentials Plus Kit?

Thank you for your answer

dario

[virtualg_uk]

Hello,

Yes the Essentials Plus kit supports HA as well as all of these features: vSphere Hypervisor, vMotion, High Availability, Data Protection, vShield Endpoint, vSphere Replication

Yes, what you are trying to do sounds good: 2 hosts and 2 datastores from a central NAS so that both datastores are available to both hosts (Shared storage)

I hope this answered your question

[Dario19]

Thank you for your answer grba.

I was thinking about of using two physical NAS, so if one of them goes down the other keep the Vms active but I think it's not possible without DRS. Is it right?

thanx.

[virtualg_uk]

You cannot natively have a VM stored on both NAS systems at the same time (a copy of it on the other NAS) but you could use vSphere Replication to replicate the VM to the other NAS.

In the event of NAS failure, you could then bring up the replicated copies of the VMs on the other NAS.

Please take a look here: https://www.vmware.com/support/pubs/vsphere-replication-pubs.html

Let us know if you need more information

[Dario19]

'you could then bring up the replicated'

So there isn't an automatic restart but I have to start it manually, is it right?

Let's say I have 2 physical hosts and 2 physical NAS:

1 Host goes down. In this case Vmware HA should automatically start the VMs on the other host.

1 NAS goes down. With Replication I have the VMs on the other one but they doesn't start.

Is it right?

One last question (for now ),

Let's suppose that my VMs use 4TB disk space on NAS, and physical host have only the VMs configuration. Does the host uses many GB or theoretically could I create a simple raid 1 with 2 little HD?

I hope you understand my question.

Thank you for your time.

ds

[virtualg_uk]

Yes, if you configure one of the NAS devices so that both host can assess it and see the datastores then HA will restart VMs on the other host if one hosts fails *YOu need to setup a cluster, put the hosts inside it and enable HA)

If the NAS fails, you can recover the VMs via vSphere Replication UI, you need to manually trigger this otherwise your VMs might get recovered during a "false positive" outage)

If the VC is down though, then you will not be able to bring up the VMs on the other host with vSphere Replication because you need the VC to be online.

Solution 1) Store the VC on the other NAS and ensure you have backups

Solution 2) In the event of main NAS failing, manually bring them online (Search datastore for the replicated VMs and add to the inventory)

Solution 3) Or build another VC (licensing?) and replicate to a Replication appliance deployted to that VC, store the VC on the other NAS

Also, ensure you are using RAID on both NAS devices to help prevent any failures.

For your other question, Your VMs disks and VMs configuration filess should all be stored on the NAS. The host requires a very small amount of space to install ESXi, depending on the evrsion of ESXi it's something like 8GB for the install and some space for logs etc. Recommended option is to install to a USB stick or SD card installed nside the host

I hope this helps, anything else just ask.

vSphere Replication, quick youtube video here: https://www.youtube.com/watch?v=8lXSQUOY9eo

[Dario19]

Wow! So I could use an high-end server without hard disk, raid, etc etc and use only one USB stick? I never would have thought it.

In this scenario my high availability seems not so high... :smileyplain:

Last question:

I've read that it's not a good idea to store SQL Server VM on a NAS due to poor performance, many people raccomend to use a local storage or a SAN.

But, If I want create a cluster I can't use local storage, and a SAN would be expensive and useless for my purposes.

What would you recommend me?

thank you

thank you

thank you

ds

[virtualg_uk · Accepted solution]

Yes many high end servers will utilise a single internal SD or USB for the ESXI installation, this is the norm now unless you can boot from SAN etc. The advantage is that there are no spinning disks to fail and SD/USB is far cheaper. When ESXi loads, it loads into memory so having a disk there is just a waste of space and money. Some systems (Dell) support redundancy on the SD cards, so you can put in 2 SD cards for the ESXi install and it will mirror one to the other. If one fails it will use the other. If you dont have this and SD fails, ESXi will still continue running until the next reboot. ESXi is very quick to install again if needed anyway.

For SQL server performance, depending on how many IOPS you require / how busy the server is, NAS can be a good option, it generally depends on how many IOPS the NAS can deliver to the application (This is determined by how many disks you have in the NAS and their type etc) See here for a calculator: Disk RAID and IOPS | The Cloud Calculator

I would vary rarely recommend standard local disk configurations for anything as you lose HA and vMotion abilities between hosts in a cluster.

SAN can have better performance but it all depends on the bandwidth available to it and the IOPS you require, for small DBs NAS can work well.