[Gluster-devel] Re: AFR load-balancing

Anand Avati avati at zresearch.com
Tue Nov 20 19:35:21 UTC 2007

> Have you tried chaining AFR volumes?  There's quite a few ways I can
> imagine reducing line saturation if that's the problem.  Here's one:
> server1 has an afr of a local volume and a volume from server2
> server3 has an afr of a local volume and a volume from server4
> client afr of server1's afr and server2's afr
> This should allow a single write from a client at 1000/8/2 = 62.5
> MByte/s.  Client writes only twice (to server1 and server3) halving the
> bandwidth.  Server1 and server3 write only once each to server2 and
> server4 respectively and receive the writes from the client, halving
> their bandwidth.
> Note: I have no idea how well this will perform in reality.  There may
> be enough lag in glusterfs chaining writes that the gains aren't worth
> it, but I suspect since it is effectively pipelining the writes along
> there won't be too much lag.

Good thought kevan, it sounds like a good in-between solution.
Jerker, this might work even better for you if the server-server
interconnects are on a seperate physical media not cascaded with the
server-client interconnect.


It always takes longer than you expect, even when you take into account
Hofstadter's Law.

-- Hofstadter's Law

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