Re: free space considerations writing bhyve image to a zvol

On Wed, Oct 18, 2023 at 05:05:57PM +0100, Martin Simmons wrote:

>How did you measure this external size?  The truncate command will create a
>file taking 0 bytes of space initially.  You need to use du linuxvm.img on the
>host to see how much is being used at the moment.

ls -lah on the host

>> If i write the vm to a 1.6Tb zvol with compression set (lz4),
>> would it be feasible to expect the vm to work?
>>
>> I expect it might break the vm's filesystem internally,
>> now, thinking about it.
>
>If the writing succeeds then I don't see how it would affect the vm's
>filesystem, because that just sees the same data regardless of how it is
>actually stored by the host.
>
>More interesting is what will happen if the vm's filesystem becomes fuller and
>the compressed size exceeds 1.6Tb.  The host will report an error, but I don't
>know if the vm will handle it gracefully (it might see it as the equivalent of
>a disk write error).

yeah, thats my concern.

I think I'll play safe and first make a 2Tb zvol space on the new host then dd
the linuxvm.img to it

thanks
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