Increasing the Size of A guestVM

[chiibuzor]

[dianpopa]

Hi!

Can you give us more details? What resource of your guestVM would you need to adjust?

[chiibuzor]

Hi, I would like to increase the size of the root partition, if possible mount another drive with a desired size. Cheers. Regards

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On Mon, Sep 5, 2022 at 4:32 PM Diana Popa ***@***.***> wrote: Hi! Can you give us more details? What resource of your guestVM would you need to adjust? — Reply to this email directly, view it on GitHub <#3110 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AK3SGZR6L2T3LZRUNHXFPPDV4YHCRANCNFSM573RAK5Q> . You are receiving this because you authored the thread.Message ID: <firecracker-microvm/firecracker/repo-discussions/3110/comments/3561267@ github.com>

[dianpopa]

Yes, you can adjust the size of a block device after boot.

You simply modify the size of the backing file on the host and then you send the patch command for the associated block device.
You can find more details here: https://github.com/firecracker-microvm/firecracker/blob/a367796e66eeac42d9ce1294c0fbbca6191e9cf3/docs/api_requests/patch-block.md.

[chiibuzor]

Thanks, I'll check it out.

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On Mon, Sep 5, 2022 at 5:51 PM Diana Popa ***@***.***> wrote: Yes, you can adjust the size of a block device after boot. You simply modify the size of the backing file on the host and then you send the patch command for the associated block device. You can find more details here: https://github.com/firecracker-microvm/firecracker/blob/a367796e66eeac42d9ce1294c0fbbca6191e9cf3/docs/api_requests/patch-block.md . — Reply to this email directly, view it on GitHub <#3110 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AK3SGZQPWS2RH7VL2DXRJU3V4YQH5ANCNFSM573RAK5Q> . You are receiving this because you authored the thread.Message ID: <firecracker-microvm/firecracker/repo-discussions/3110/comments/3562185@ github.com>

[WeeJeWel]

Is there also something documented, so that the (.ext4) file on the host only takes up what's actually inside, but can grow up to a certain limit? Similar to how many popular VM solutions do it (e.g. VMWare, Parallels).

[ShadowCurse]

Hi @WeeJeWel, Firecracker does not do any specific setup for this to work. You can look at the fallocate and see if it helps.

[pb8o]

truncate -s SIZE should also create a sparse file. I.e.

truncate -s 1G mydisk
mkfs.ext4 mydisk
# add some data 
truncate -s 2G mydisk
resize2fs mydisk