[Openstack] SWIFT AND RING QUESTION

John Dickinson me at not.mn
Wed Aug 20 01:00:45 UTC 2014


https://swiftstack.com/blog/2012/11/21/how-the-ring-works-in-openstack-swift/ is soemthing that should be able to give you a pretty complete overview of how the ring works in Swift and how data placement works.

Let me know if you have more questions after you watch that video.

--John






On Aug 19, 2014, at 5:34 PM, Brent Troge <brenttroge2016 at gmail.com> wrote:

> 
> Excuse this question and for lack of basic understanding. I dropped from school at 8th grade, so everything is basically self taught. Here goes.
> 
> I am trying to figure out where each offset/partition is placed on the ring.
> 
> 
> So If I have 50 drives with a weight of 100 each I come up with the below part power
> 
> part power = log2(50 * 100) = 13
> 
> Using that I then come up with the amount of partitions.
> 
> partitions = 2^13 =  8192
> 
> Now here is where my ignorance comes into play. How do I use these datapoints to determine where each offset is on the ring?
> 
> I then guess that for each offset they will have a fixed range of values that map to that partition.
> 
> So for example, for offset 1, all object URL md5 hashes that have a decimal value of 0 through 100 will go here(i just made up the range 0 through 100, i have no idea what the range would be with respect to my given part-power, drive, etc).   
> _______________________________________________
> Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> Post to     : openstack at lists.openstack.org
> Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <http://lists.openstack.org/pipermail/openstack/attachments/20140819/d4df265f/attachment.sig>


More information about the Openstack mailing list