In the community forums there was a nice little tip that you can run Replication Factor 2 on a single node cluster running Community Edition. Off course I needed to test this out. I installed CE on a VM as described here. I only changed the disks to the following: 2x 250GB for CVM en 2x 500GB for data (128GB is for AHV/Boot):
During installation these are my settings:
After installation is finished make a new cluster with the following command: cluster -s 10.0.0.81 –redundancy_factor=2 create
When the cluster is created and started, login into Prism Element and have a look at the storage containers:
That is pretty cool.
Hi so with this setup, can you tolerate a data drive failure too?
Yes you can 👍🏻
Oh brilliant, I’ll feel much happier running this as my home lab then – thanks for showing this off! (BTW Hi fellow NTC 🙂 )
Just to confirm this does work – I have a server with two SSDs and three HDDs:
nutanix@NTNX-39e1c69b-A-CVM:192.168.250.221:~$ ncli cluster get-domain-fault-tolerance-status type=disk
Domain Type : DISK
Component Type : METADATA
Current Fault Tolerance : 1
Fault Tolerance Details :
Last Update Time : Sun Jan 12 22:30:11 UTC 2025
Domain Type : DISK
Component Type : FREE_SPACE
Current Fault Tolerance : 1
Fault Tolerance Details :
Last Update Time : Sun Jan 12 23:15:41 UTC 2025
nutanix@NTNX-39e1c69b-A-CVM:192.168.250.221:~$ ncli cluster get-redundancy-state
Current Redundancy Factor : 2
Desired Redundancy Factor : 2
Redundancy Factor Status : kCassandraPrepareDone=true;kZookeeperPrepareDone=true
And the ‘resilient capacity’ is shown on the Storage widget on the Prism homepage.
Thanks for this!
But I installed CE 2.1 with 4 SSD. One AHV, one CVM, and two identical data drives. Can I add another CVM and make both mirrors?
No you need to reinstall and select the disks correctly during installation.
That’s what I was afraid of… well at least it’s now working with CE 2.1 and I didn’t get very far so blown away and reconfiguring now.
I have twin 250GB for CVM and twin 2TB for data
One other query. My VM AHV has like 48 GB of RAM… is there a reason I can’t increase the CVM from 16 to 32 or even 20? GUI tells me all nodes have too little memory but it’s a single node of 16
HEre is explained how to change the cvm memory: https://www.jeroentielen.nl/change-nutanix-community-edition-cvm-memory/