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Where CVM reside ?

  • 11 June 2016
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I have a misunderstanding about CVM location for a long time: I think CVM and hypervisor locate in SATA-DOM all. foundation install hypervisor, then install CVM, then CVM utilize NDFS to manage whole disks, untill while reading how to replace I found a Caution:
“Caution: Do not use this procedure to replace Controller VM boot drives on systems that have asingle SSD (such as NX-1020, NX-1050, NX-1065S, NX-1065-G4, NX-6020 and NX-6035C). Forthese platforms, follow the Boot/Metadata Drive Replacement Documentation.”

Does CVM boot drive refer to physical locaton of CVM ? SATADOM always only contains Hypervisor ? no matter one or two ssd Nutanix hardware platfrom ?

If it`s true, what process foundation works ? how the NDFS manager disks and RF to protect CVM data itself ? it seems raid1 will be used for two SSD platform ?NDFS used for the remainning HDD ?

also I just can`t find

thanks in advance
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Best answer by Jon 13 June 2016, 03:47

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RE What lives on the SATADOM and how does the CVM boot
The SATADOM houses the hypervisor and the base "configuration" file for the CVM, as well as a small ISO called svmboot.iso

In ESXi, the configuration file is called a VMX, and it defines how the CVM is configured for resources, as well as calling out the svmboot.ISO as a device that the CVM always boots off of.

Note: way back in the early days of Nutanix, the CVM was called the "SVM", hence this name as stuck around internally on a few items, such as svmboot.iso

The svmboot.iso contains a very small program that helps the CVM boot from the Active partition for Nutanix home os, which lives bare metal on the SSD's within the system.

NOTE: This specific topic is not yet covered in the Nutanix Bible, I asked the author  to update this when he gets time.

RE Single vs Dual SSD systems - replacing SSD's
In a single SSD system, that means that the Nutanix OS for that specific node only lives on that single SSD, so there are some special instructions to replace SSD's in a single SSD system.

Note: CVM's are almost 100% stateless, so losing that SSD and the Nutanix OS on it really doesn't matter at all, as there is a very well defined recovery procedure. We're making this procedure even easier in a very soon upcoming release, so it will all be driven right from the GUI. Very easy.

In a dual SSD system, we actually mirror the nutanix OS across both SSD's, using mdraid.

This means that either one of those SSD's could fail, and all you have to do is follow the very easy hot-swap procedures. After the new SSD is put in, the mdraid will re-sync, and everything is fine.

NOTE: this mdraid is ONLY for the nutanix os, and is not used for anything else.

Boot / Metadata replacement documentation for single SSD:
https://portal.nutanix.com/#/page/docs/details?targetId=Boot_Metadata_Drive_Replacement_Single_SSD-Acr_v4_6-NX1000_NX6000:Boot_Metadata_Drive_Replacement_Single_SSD-Acr_v4_6-NX1000_NX6000


RE Foundation
First, please make sure you read the entire Field Install Guide, as the content will help you understand foundation better:
https://portal.nutanix.com/#/page/docs/details?targetId=Field_Installation_Guide-v3_1:Field_Installation_Guide-v3_1



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Userlevel 7
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-

RE What lives on the SATADOM and how does the CVM boot
The SATADOM houses the hypervisor and the base "configuration" file for the CVM, as well as a small ISO called svmboot.iso

In ESXi, the configuration file is called a VMX, and it defines how the CVM is configured for resources, as well as calling out the svmboot.ISO as a device that the CVM always boots off of.

Note: way back in the early days of Nutanix, the CVM was called the "SVM", hence this name as stuck around internally on a few items, such as svmboot.iso

The svmboot.iso contains a very small program that helps the CVM boot from the Active partition for Nutanix home os, which lives bare metal on the SSD's within the system.

NOTE: This specific topic is not yet covered in the Nutanix Bible, I asked the author  to update this when he gets time.

RE Single vs Dual SSD systems - replacing SSD's
In a single SSD system, that means that the Nutanix OS for that specific node only lives on that single SSD, so there are some special instructions to replace SSD's in a single SSD system.

Note: CVM's are almost 100% stateless, so losing that SSD and the Nutanix OS on it really doesn't matter at all, as there is a very well defined recovery procedure. We're making this procedure even easier in a very soon upcoming release, so it will all be driven right from the GUI. Very easy.

In a dual SSD system, we actually mirror the nutanix OS across both SSD's, using mdraid.

This means that either one of those SSD's could fail, and all you have to do is follow the very easy hot-swap procedures. After the new SSD is put in, the mdraid will re-sync, and everything is fine.

NOTE: this mdraid is ONLY for the nutanix os, and is not used for anything else.

Boot / Metadata replacement documentation for single SSD:
https://portal.nutanix.com/#/page/docs/details?targetId=Boot_Metadata_Drive_Replacement_Single_SSD-Acr_v4_6-NX1000_NX6000:Boot_Metadata_Drive_Replacement_Single_SSD-Acr_v4_6-NX1000_NX6000


RE Foundation
First, please make sure you read the entire Field Install Guide, as the content will help you understand foundation better:
https://portal.nutanix.com/#/page/docs/details?targetId=Field_Installation_Guide-v3_1:Field_Installation_Guide-v3_1
Userlevel 1
Badge +14
Hello, Jon
thanks a million for your patience and detailed repy. really makes me more clear about Nutanix
RE FOUNDATION
In fact, I have readen Field install guide twice, and just can`t understand the more background image step, it mainly shows procedures step by step to install image.
and I have posted similar questions dedicated to Foundation in the path:
Nutanix Community>All About Nutanix>Installation & Configuration>difference between Phoenix, NOS, AOS

there are many terminologies and sofware updates so fast, I just can find and keep up with it from Nutanix train and colleague guys
Userlevel 7
Badge +30
I'll reply to the other thread in a little bit, it's a long thread.

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