Forwarded per Ben's request.

---------- Forwarded message ---------- From: Ben Hartshorne bhartshorne@wikimedia.org Date: Tue, Jan 31, 2012 at 8:43 PM Subject: [Wikitech-l] Deploying Swift for thumbnails next Mon-Thurs Feb 6-9 To: Wikimedia developers wikitech-l@lists.wikimedia.org

Hi Everyone,

Next week we're going to switch the back end system that hosts thumbnail[1] images.  We have been using ms5http://ganglia.wikimedia.org/latest/?r=day&cs=&ce=&m=&c=Miscellaneous+pmtpa&h=ms5.pmtpa.wmnet(a Sun server running linux) to serve all thumbnails.  We are switching to Openstack Swift http://wikitech.wikimedia.org/view/Swift, a clustered object store.  Though we have done testing and expect no problems, I want to publicize the change so that if issues do appear, they are quickly directed to the right place.

Here's the schedule: * Monday Feb 6th: move 0.4% of all thumbnail traffic from ms5 to swift. Only thumbnails with "/thumb/a/a2/"[2] in the URL will be affected. * Tuesday: move 12.5% of traffic - thumbnails with "/thumb/a/" or "/thumb/b/" will be affected * Wednesday: move 50% of traffic - thumbnails with "/thumb/(a-f or 0 or 1)/" will be affected * Thundlay: move 100% of traffic - all thumbnails will be served from Swift

Potential symptoms that might  be related to this change on Monday: * a thumbnail image with /a/a2/ simply fails to load ** try changing the number preceding 'px' to generate a different size image[3] * you delete an image and the thumbnail is still available ** try purging the cache[4] and see if that makes it go away ** try changing the number preceding 'px' and see what happens * you move an image to a new name and it's still available at the old name, when either the new or old name has /a/a2/ in the URL ** please provide full URLs for both the new and old names

If any of these things happen, or if something else odd happens with images or thumbnails and you feel it might be related, please join #wikimedia-tech in IRC and ping me (maplebed) or Aaron (AaronSchulz).  If neither of us are available or you would prefer to just leave us a message, add a note to https://www.mediawiki.org/wiki/SwiftMedia/Issues.  :)  If things are severely broken, you can ask someone in the #wikimedia-tech to page me.

Thanks for your help!

-ben

[1] In case you don't know what I mean by thumbnail images, I'm talking about all URLs that start http://upload.wikimedia.org/ and have /thumb/ in the path.  When an image is uploaded to a wiki (or commons), Mediawiki automatically generates scaled versions of the image.  These are what I call 'thumbnails'.  Nearly every time an image is used in a wiki page it is actually a thumbnail being used.  Try going to any wiki page with an image, right click on the image, and choose 'view image'.  You'll get something like http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Liberty_Head_Nickel...] as the URL (this was taken from enwiki's featured article today)

[2] For example, http://upload.wikimedia.org/wikipedia/commons*/thumb/a/a2/*Little_kitten_.jp... [6]

[3] For example, http://upload.wikimedia.org/wikipedia/commons/thumb/a/a2/Little_kitten_.jpg/ *799px*-Little_kitten_.jpg

[4] Find the URL for the main image file (rearrange the URL to find the original image - /wikipedia/commons -> commons.wikipedia.org) and add "?action=purge" to the end of the URL (eg http://commons.wikimedia.org/wiki/File:Little_kitten_.jpg?action=purge

[5] Image in the public domain

[6] cc-by 3.0, Alexanderwdarkhttp://commons.wikimedia.org/w/index.php?title=User:Alexanderwdark&action=edit&redlink=1 _______________________________________________ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l