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From Mike Tutkowski <>
Subject Re: Storage Quality-of-Service Question
Date Thu, 31 Jan 2013 23:33:18 GMT
Thanks for the info, Marcus!

So, you are thinking that when the user creates a new Disk Offering that he
or she would be given the option of specifying Max and Min IOPS?  That
makes sense when I think of Data Disks, but how does that figure into the
kind of storage a VM Instance runs off of?  I thought the way that works
today is by specifying in the Compute Offering a Storage Tag.


On Thu, Jan 31, 2013 at 4:25 PM, Marcus Sorensen <>wrote:

> So, this is what Edison's storage refactor is designed to accomplish.
> Instead of the storage working the way it currently does, creating a
> volume for  a VM would consist of the cloudstack server (or volume
> service as he has created) talking to your solidfire appliance,
> creating a new lun, and using that. Now instead of a giant pool/lun
> that each vm shares, each VM has it's own LUN that is provisioned on
> the fly by cloudstack.
> It sounds like maybe this will make it into 4.1 (I have to go through
> my email today, but it sounded close).
> Either way, it would be a good idea to add this into the disk
> offering, a basic IO and throughput limit, and then whether you
> implement it through cgroups on the Linux server, or at the SAN level,
> or through some other means on VMware or Xen, the values are there to
> use.
> On Thu, Jan 31, 2013 at 4:19 PM, Mike Tutkowski
> <> wrote:
> > Hi everyone,
> >
> > A while back, I had sent out a question regarding storage quality of
> > service.  A few of you chimed in with some good ideas.
> >
> > Now that I have a little more experience with CloudStack (these past
> couple
> > weeks, I've been able to get a real CS system up and running, create an
> > iSCSI target, and make use of it from XenServer), I would like to pose my
> > question again, but in a more refined way.
> >
> > A little background:  I worked for a data-storage company in Boulder, CO
> > called SolidFire (  We build a highly
> fault-tolerant,
> > clustered SAN technology consisting exclusively of SSDs.  One of our main
> > features is hard quality of service (QoS).  You may have heard of QoS
> > before.  In our case, we refer to it as hard QoS because the end user has
> > the ability to specify on a volume-by-volume basis what the maximum and
> > minimum IOPS for a given volume should be.  In other words, we do not
> have
> > the user assign relative high, medium, and low priorities to volumes (the
> > way you might do with thread priorities), but rather hard IOPS limits.
> >
> > With this in mind, I would like to know how you would recommend I go
> about
> > enabling CloudStack to support this feature.
> >
> > In my previous e-mail discussion, people suggested using the Storage Tag
> > field.  This is a good idea, but does not fully satisfy my requirements.
> >
> > For example, if I created two large SolidFire volumes (by the way, one
> > SolidFire volume equals one LUN), I could create two Primary Storage
> types
> > to map onto them.  One Primary Storage type could have the tag
> "high_perf"
> > and the other the tag "normal_perf".
> >
> > I could then create Compute Offerings and Disk Offerings that referenced
> > one Storage Tag or the other.
> >
> > This would guarantee that a VM Instance or Data Disk would run from one
> > SolidFire volume or the other.
> >
> > The problem is that one SolidFire volume could be servicing multiple VM
> > Instances and/or Data Disks.  This may not seem like a problem, but it is
> > because in such a configuration our SAN can no longer guarantee IOPS on a
> > VM-by-VM basis (or a data disk-by-data disk basis).  This is called the
> > Noisy Neighbor problem.  If, for example, one VM Instance starts getting
> > "greedy," it can degrade the performance of the other VM Instances (or
> Data
> > Disks) that share that SolidFire volume.
> >
> > Ideally we would like to have a single VM Instance run on a single
> > SolidFire volume and a single Data Disk be associated with a single
> > SolidFire volume.
> >
> > How might I go about accomplishing this design goal?
> >
> > Thanks!!
> >
> > --
> > *Mike Tutkowski*
> > *Senior CloudStack Developer, SolidFire Inc.*
> > e:
> > o: 303.746.7302
> > Advancing the way the world uses the
> > cloud<>
> > *™*

*Mike Tutkowski*
*Senior CloudStack Developer, SolidFire Inc.*
o: 303.746.7302
Advancing the way the world uses the

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