[Gluster-devel] Re: [Gluster-users] I/O fair share to avoid I/O bottlenecks on small clsuters

Gordan Bobic gordan at bobich.net
Sun Jan 31 13:52:27 UTC 2010

Traffic shaping with tc and iptables are your friends. ;)
Of course, if you are genuinely running out of bandwidth nothing will 
solve the lack of bandwidth, but if you merely need to make sure it is 
distributed more fairly and sensibly between the machines, it can be done.

Typically I would put each guest VM into a class limited to 50% of the 
host bandwidth, and put them at equal priority, with a few packet 
scheduling tweaks (e.g. prioritizing small packets, ACKs, ssh, ping, 
etc.) That way the network I/O can be kept responsive, while no one VM 
would be allowed to eat all the available bandwidth.


Mickey Mazarick wrote:
> Can you tell us a little more about your setup? I'm running many 
> hundreds of vms on our cluster but I found infiniband is necessary if 
> you have any large amount of io (databases, lots of drive access etc).
> You may simply be saturating your io if you only have a single gigabit 
> interface to your storage. Things like NFS mount can direct all your io 
> down one gig link and can be the death knell to your distributed 
> parallel filer.
> -Mic
> Ran wrote:
>> Hi ,
>> I recently posted an issue regarding a situation that happen when
>> say 1 virtual machine images takes down the entire server IO
>> then the entire storage become slow in such way that noting work
>> emails , web etc...
>> gluster gays posted that virtual machine is a main goal of the storage
>> and that they probebly implement a fair share IO options to avoid this 
>> cases .
>> Can anyone tell me what are the plans for this , it apear to me that
>> this is 1 of the most important issues on such storage seens it is not
>> possible to run more then a few virtual machins in parallel .
>> Many thanks ,
>> _______________________________________________
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>> Gluster-users at gluster.org
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