On Mon, Nov 30, 2015, at 12:29, Giuseppe Ragusa wrote:
> Hi all,
> I'm writing as a followup to a related wishlist item that I recently posted 
> on the oVirt users mailing list (see the last point in 
> http://lists.ovirt.org/pipermail/users/2015-November/036048.html ).
> 
> As far as I know, GlusterFS currently supports specifying a bandwidth limit 
> only for geo-replication traffic.
> 
> On the other side, it is my understanding that a cluster where peers have 
> been probed on a separate, dedicated network (accessed by all peers with 
> dedicated NICs) will automatically relegate heal/rebalance/etc traffic (I 
> mean: anything besides client-related traffic) to that network, so that if 
> you have a different client-facing network the aforementioned goal should be 
> already attainable (to be honest: even in that scenario, a CPU limiting 
> feature for those heal/rebalance/etc tasks could be needed but currently I 
> think it is possible only to limit glusterd/glusterfsd as a whole).

After some reading of GlusterFS proposed specs [1] I must partially correct my 
statement above by specifying that the above holds true only (barrying some 
specific DNS/routing/firewalling tricks) if clients use NFS/Samba (generally 
anything besides FUSE/libgfapi) to access GlusterFS cluster servers.

> The main scope for the present RFE is to allow bandwidth limiting for those 
> cases where peers are clients too (and maybe the only clients), just like in 
> an hyperconverged oVirt setup.

Further reading through linked discussions [2] brought up a possible way to 
achieve the goal in the servers-are-clients case by offloading (separately: 
heal/rebalance vs clients) traffic to many separate networks once the 
Split-Network spec will be implemented; I still think that the QoS-facilitating 
changes proposed below could be useful by themselves and maybe of easier 
implementation (is 3.8 stuff still open for small proposals?).


[1] 
https://github.com/gluster/glusterfs-specs/blob/master/in_progress/Split%20Network.md

[2] http://www.gluster.org/pipermail/gluster-users/2014-November/019471.html

> As a final note, it would be fine if the goal could be reached by OS-level 
> means, as with QoS policy, but this too seems not possible at the moment: 
> maybe by allowing to specify dedicated fixed ports for heal/rebalance/etc 
> outgoing traffic then we could apply some traffic control to those ports only.
> 
> Many thanks in advance for your attention and excuse me for any 
> errors/misunderstandings on my part.
> 
> Regards,
> Giuseppe
> 
> PS: sorry if this gets double-posted, but I initially forgot to use the 
> subscribed email address when sending
> 
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