From: "DERUMIER, Alexandre via pve-devel" <pve-devel@lists.proxmox.com>
To: "pve-devel@lists.proxmox.com" <pve-devel@lists.proxmox.com>,
"f.ebner@proxmox.com" <f.ebner@proxmox.com>,
"f.gruenbichler@proxmox.com" <f.gruenbichler@proxmox.com>
Cc: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
Subject: Re: [pve-devel] [PATCH-SERIES v3 pve-storage/qemu-server/pve-qemu] add external qcow2 snapshot support
Date: Mon, 13 Jan 2025 11:58:04 +0000 [thread overview]
Message-ID: <mailman.248.1736769487.441.pve-devel@lists.proxmox.com> (raw)
In-Reply-To: <a09b6f3d-c0bc-4694-9735-7a455ae4c209@proxmox.com>
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From: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
To: "pve-devel@lists.proxmox.com" <pve-devel@lists.proxmox.com>, "f.ebner@proxmox.com" <f.ebner@proxmox.com>, "f.gruenbichler@proxmox.com" <f.gruenbichler@proxmox.com>
Subject: Re: [pve-devel] [PATCH-SERIES v3 pve-storage/qemu-server/pve-qemu] add external qcow2 snapshot support
Date: Mon, 13 Jan 2025 11:58:04 +0000
Message-ID: <2cbef7d2a33ed5ea6fab15b97f611fc4bf207c0f.camel@groupe-cyllene.com>
>>For almost all QMP commands, we only need to care about the node
>>that's
>>inserted for the drive.
(yes, that the throttle group in my implementation, and I have a fixed
name, I'm reusing the "drive-(ide|scsi|virtio)x naming"
>>And for your use-case, checking that the top
>>node of the chain matches what we expect is already a good first
>>step.
>>The lookup itself is a different question, I'll also answer to the
>>other
>>mail.
Maybe this could help to understand the problem:
Here a small resume of the 2 workflow, snapshot && block mirror,
where we have a switch between nodes:
snapshot
--------
--------
a) renaming current
--------------------
1)
device--->throttle-group--->fmt-node1----->file-node1 ----> vm-100-
disk-0.qcow2
2) create a new file node with new file name
device--->throttle-group--->fmt-node1----->file-node1 ----> vm-100-
disk-0.qcow2
file-node2 --> vm-100-disk-0-snap1.qcow2
3) switch the file node with blockdev-reopen
device--->throttle-group--->fmt-node1----->file-node2 ---> vm-100-disk-
0-snap1.qcow2
file-node1 --> vm-100-disk-0.qcow2
4) delete the old filenode
device--->throttle-group--->fmt-node1----->file-node2 ---> vm-100-disk-
0-snap1.qcow2
b) create the new current
-------------------------
1) add a new fmt node
device--->throttle-group--->fmt-node1----->file-node2 ---> vm-100-disk-
0-snap1.qcow2
fmt-node3----->file-node3----->vm-100-disk-0.qcow2
2) blockdev-snapshot -> set fmt-node3 active with fmt-node1 as backing
device--->throttle-group--->fmt-node3----->file-node3----->vm-100-disk-
0.qcow2
|
|--> fmt-node1----->file-node2 ---> vm-
100-disk-0-snap1.qcow2
mirror
--------
--------
1)
device--->throttle-group--->fmt-node1----->file-node1 ----> vm-100-
disk-0.qcow2
2) add a new target fmt + file node
device--->throttle-group--->fmt-node1----->file-node1 ----> vm-100-
disk-0.qcow2
fmt-node2----->file-node2 ----> vm-100-disk-1.qcow2
3) blockdev-mirror (mirror + switch the fmt node on complete)
device--->throttle-group--->fmt-node2----->file-node2 ----> vm-100-
disk-1.qcow2
fmt-node1----->file-node1 ----> vm-100-disk-0.qcow2
4) delete the old fmt+file node
device--->throttle-group--->fmt-node2----->file-node2 ----> vm-100-
disk-1.qcow2
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next prev parent reply other threads:[~2025-01-13 11:58 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-16 9:12 Alexandre Derumier via pve-devel
2025-01-09 14:13 ` Fabian Grünbichler
2025-01-10 7:44 ` DERUMIER, Alexandre via pve-devel
2025-01-10 9:55 ` Fiona Ebner
2025-01-10 12:30 ` DERUMIER, Alexandre via pve-devel
[not found] ` <8f309dfe189379acf72db07398a37a98e8fc3550.camel@groupe-cyllene.com>
2025-01-13 10:06 ` Fiona Ebner
2025-01-13 10:54 ` Fiona Ebner
2025-01-13 10:57 ` DERUMIER, Alexandre via pve-devel
2025-01-13 11:54 ` Fiona Ebner
2025-01-13 11:58 ` DERUMIER, Alexandre via pve-devel [this message]
[not found] ` <2cbef7d2a33ed5ea6fab15b97f611fc4bf207c0f.camel@groupe-cyllene.com>
2025-01-13 13:42 ` Fiona Ebner
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