cloudstack-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Chiradeep Vittal <Chiradeep.Vit...@citrix.com>
Subject Re: NFS speed traffic control
Date Mon, 24 Sep 2012 17:27:59 GMT
CloudStack supports tagging physical resources [1]. A service offering or
disk offering can include these tags. During deployment of the VM and
volume, 
these tags will be taken as hints.
You could have 2 types of primary storage per cluster: one tagged "high
priority" 
and one tagged "low priority". Of course there's still variables such as
shared network bandwidth and contention for dom0 resources.

[1] http://wiki.cloudstack.org/display/COMM/Host+tags+and+Storage+tags


On 9/24/12 12:15 AM, "Shanker Balan" <mail@shankerbalan.net> wrote:

>On 24-Sep-2012, at 6:02 AM, Ivan Rodriguez <ivanoch@gmail.com> wrote:
>
>> Dear Cloudstack users,
>> 
>> We have several servers provisioning vm's through cloudstack, our
>>primary
>> storage is coming from a NFS mount point,  we have some high demanding
>>and
>> important vm's  and some which are not that important but do lots of
>>writes
>> to the disk, since all the vm's are competing for access to the NFS
>>disk,
>> one vm can affect the speed of the whole setup, I know cloudstack can
>> manage network speed shaping, but I haven't found a way to do network
>> storage speed quota or something like that do you guys know if this is
>> something that we can do inside cloudstack ?
>
>AWS provides a "Provisioned IOPS" feature for their storage offerings.
>This allows for predictable IO performance to the instances.
>
>http://aws.amazon.com/about-aws/whats-new/2012/07/31/announcing-provisione
>d-iops-for-amazon-ebs/
>
>NFS by itself cannot do much to guarantee predictable performance. A
>simple network rate limit can control overall throughput but cannot
>prevent a tenant from performing massive number of small IO operations on
>their virtual disk like what a database would usually do. End of the day,
>NFS does not do multi tenancy very well.
>
>I am guessing that an AWS style "Provisioned IOPS" like "feature" can be
>implemented by having a storage layer that understands multi tenancy and
>natively provides an API to limit/guarantee raw read/write IO operations
>on a per file/object/directory basis. Basically, a storage layer that
>does QoS on a wide range of factors. Cloudstack can then use these native
>APIs to set the desired PIOPS while provisioning instances using a plugin
>connector.
>
>Xenserver seems to allow for I/O priority QoS on the virtual disk. I am
>not sure if this is possible for NFS. The doc seems to suggest that its
>for multiple hosts accessing the same LUN.
>
>http://support.citrix.com/servlet/KbServlet/download/28751-102-673823/XenS
>erver-6.0.0-reference.pdf
>
>A workaround would be to have multiple PODs having different QoS
>characteristics - low IO, medium IO, high IO and a very high IO PODs.
>Each POD can use a different primary storage with desired IO
>characteristics or maybe a shared primary storage with QoS features
>enabled.
>
>Am hoping others can share their experiences handling performance
>expectations in a multi tenant cloud using shared storage. Its a very
>interesting problem to solve as clouds in general are notorious for their
>IO performances.
>
>Hth.
>
>--  
>Shanker Balan
>@shankerbalan


Mime
View raw message