Re: [RFC] Live resize of backing device

[Coly Li <colyli@suse.de>]

> 2023年1月27日 20:44，Andrea Tomassetti <andrea.tomassetti-opensource@devo.com> 写道：
> 
> From 83f490ec8e81c840bdaf69e66021d661751975f2 Mon Sep 17 00:00:00 2001
> From: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
> Date: Thu, 8 Sep 2022 09:47:55 +0200
> Subject: [PATCH v2] bcache: Add support for live resize of backing devices
> 
> Signed-off-by: Andrea Tomassetti <andrea.tomassetti-opensource@devo.com>
> ---
> Hi Coly,
> this is the second version of the patch. As you correctly pointed out,
> I implemented roll-back functionalities in case of error.
> I'm testing this funcionality using QEMU/KVM vm via libvirt.
> Here the steps:
>  1. make-bcache --writeback -B /dev/vdb -C /dev/vdc
>  2. mkfs.xfs /dev/bcache0
>  3. mount /dev/bcache0 /mnt
>  3. dd if=/dev/random of=/mnt/random0 bs=1M count=1000
>  4. md5sum /mnt/random0 | tee /mnt/random0.md5
>  5. [HOST] virsh blockresize <vm-name> --path <disk-path> --size <new-size>
>  6. xfs_growfs /dev/bcache0
>  6. Repeat steps 3 and 4 with a different file name (e.g. random1.md5)
>  7. umount/reboot/remount and check that the md5 hashes are correct with
>        md5sum -c /mnt/random?.md5

[snipped]

Hi Andrea,

For the above step 5, could you provide a specific command line for me to reproduce?

I tried to resize the disk by virus from 400G to 800G, the disk resize doesn’t happen online, I have to stop and restart the virtual machine and see the resized disk.

Thanks.

Coly Li