independent persistent and non persistent

[Bab]

Dear all

Hi

these are my experience about independet persistent disk

and independent non persistent disk on windows server2016

on first vm i create an independent persistent disk and with just can not get snapshot from that vm's disk is ibdependet persistent

and on second vm that add an independent non persistent disk in this mode

1- could not get snapshot

2- after restart vm disks with type independent non persistent will be remove from my computer and from computer managment /Disk

had to add it

is that correct ?

because i thought we have a feature in independent disk that every thing that write on that disk will be delete afer restart but here the disk will be remove from my computer

Is that correct ?

BR

Babak

[daphnissov]

You need to go back and read to understand how these disk types work. Cormac has a good article here.

[Bab]

So thanks

but in some article said :

independent-persistent mode and independent-non-persistent mode can not get snapshot when my vm is power-on and if we power-off vm it can get snapshot but in that article i could not find this

i have read many article and could not find any about these :

1- i can get snapshot from vm with independent-disk when is power-off

2- when i create  an independent-non-persistent mode in my vm after restart or power-off vm it will be delete my virtual disk from OS but in article i read that when create a virtual disk with independent-non persistent after restart vm just data on disk will be delete but now after restart my virtual disk will be remove and had to add it manually from disk managment

what is the  problem ?

BR

[daphnissov]

1- i can get snapshot from vm with independent-disk when is power-off

No, if a disk is in Independent Persistent mode, you cannot take a snapshot of it regardless of its power state. Try it for yourself. Set the disk to Independent Persistent and power it up. Now take a snapshot. The snapshot operation completes, but if you edit the VM's configuration you'll see it is not referencing any snapshot file. Browse the datastore to confirm. So if there's no snapshot, everything is persisted to disk immediately and is "permanent".

2- when i create  an independent-non-persistent mode in my vm after restart or power-off vm it will be delete my virtual disk from OS but in article i read that when create a virtual disk with independent-non persistent after restart vm just data on disk will be delete but now after restart my virtual disk will be remove and had to add it manually from disk managment

This English is difficult to understand and I don't entirely follow you. There is no "delete my virtual disk from OS" when you restart or power cycle a VM which has Independent Non-Persistent mode set, however it will roll-back any changes made from the time you powered it on to the time you power cycled it. This is how that mode works. If you had to add the disk manually again (assuming Windows) from Disk Management, then something else was going on. It doesn't affect whether disks are unmounted or mounted from the guest's perspective.

[Bab]

Can i set windows installation disk (C drive) type independent-non persistent disk during create vm ?

BR

[daphnissov]

Why would you ever want to do that?

[Bab]

because want everyone used that vm after finished work with restart vm every change that user did redo to previous state

now please see attach pic i have added an independent-non persistent disk type with 3GB size to my vm but after restart my disk will be remove from OS and had to add it manually to os please see attach pic

[daphnissov]

You probably added that new 3 GB disk and made it Independent Non-Persistent at that time. What you need to do is make it a regular Dependent disk when you first add it, bring up your VM, mount and format the disk, and make whatever changes you want to it. Once you reach that steady state you wish to preserve (and disallow changes going forward), THEN shut it down and change the disk type to Independent Non-Persistent. Otherwise, when you do it at the time of disk creation, the next time you power cycle the VM it reverts to the pre-mounted and formatted state, which is what you're showing.