[systemd-devel] persisting sriov_numvfs

["Jóhann B. Guðmundsson"]

On 01/27/2015 01:41 PM, Martin Polednik wrote:
>
> ----- Original Message -----
>> From: "Lennart Poettering" <lennart at poettering.net>
>> To: "Martin Polednik" <mpolednik at redhat.com>
>> Cc: "Andrei Borzenkov" <arvidjaar at gmail.com>, systemd-devel at lists.freedesktop.org, ibarkan at redhat.com
>> Sent: Tuesday, January 27, 2015 2:21:21 PM
>> Subject: Re: [systemd-devel] persisting sriov_numvfs
>>
>> On Tue, 27.01.15 07:35, Martin Polednik (mpolednik at redhat.com) wrote:
<snip>
>> Hmm, so there are three options I think.
>>
>> a) Expose this in networkd .netdev files, as I suggested
>>     originally. This would be appropriate if we can add and remove VFs
>>     freely any time, without the other VFs being affected. Can you
>>     clarify whether going from let's say 4 to 5 VFs requires removing
>>     all VFs and recreating them? THis would be the nicest exposure I
>>     think, but be specific to networkd.
> Removing and recreating the VFs is unfortunately required when changing the
> number of them (both ways - increasing and decreasing their count).
>
>

How common is that in practice to change the number of vf as opposed to 
admins simply take down the vNIC interface ( link set <vf> down) 
reconfigure it and start it again if when it would be but back into use?

And what would be considered as an sane default to do here in link file(s)

Always enable SR-IOV and always create numvfs equalling to totalvfs so 
for intel based cards it might look something like this ( adminstrators 
would have to overwrite to disable sr-iov and or reduce number of vf )

.link

[Match]
Driver=igb
Path=pci-0000:01:00.0-*
...

[Link]
Name=enp1s0
...

Or never configured this out of the box as in the admin has to manually 
do it himself which would make this look like something like this to 
enable SRIOV and setting the numvfs ( and or overwrite the default ) ..
.link

[Match]
Driver=igb
Path=pci-0000:01:00.0-*
Sriov=yes
Numvfs=7
...

[Link]
Name=enp1s0
...

Does not udev-builtin-net be updated to assign a ( persistent ) name to 
VF devices based upon the name of the PF ( something like 
enp1s0vf1,enp1s0vf2 etc based on the sample above)?
As well as provide persistent mac addresses for those VF's out of the 
box as an default since it seems to be a common thing to hack up via 
bootup script and or atleast be configured to do so ( PersistantMac=yes 
which is generated based on the mac address of the PF device maybe ?).


JBG