-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 At first I thought this was to allow the OSDs to stub the location of the real data after a CRUSH map change so that it didn't have to relocate the data right away (or at all) and reduce the number of map changes. Then I realized it was for cold storage tiering. Is the idea to be able to move data off to near-line storage like tape? Thanks, - ---------------- Robert LeBlanc GPG Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 On Wed, May 27, 2015 at 2:39 AM, Marcel Lauhoff wrote: > Hi, > > I wrote a prototype for an OSD-based object stub feature. An object stub > being an object with it's data moved /elsewhere/. I hope to get some > feedback, especially whether I'm on the right path here and if it > is a feature you are interested in. > > > > Code is in my "osd-stubs" branch: > https://github.com/ceph/ceph/compare/master...irq0:osd-stubs > https://github.com/irq0/ceph/tree/osd-stubs > > Tools to toy around with osd-stubs + web server to send stubs to: > https://github.com/irq0/ceph_osd-stub_tools > > > > Related: > - https://wiki.ceph.com/Planning/Blueprints/%3CSIDEBOARD%3E/osd:_tiering:_object_redirects > > > > Implementation: > > Adds two new OSD OPs: > - STUB :: Move data away; Save location in xattr; Set > object_info_t::stub_state to 'remote' > - UNSTUB :: Get data back; Remove xattr; Set object_info_t::stub_state > to 'local' > > > STUB is meant to be called by an external archive agent. UNSTUB > implicitly when OPs come in that need the object's data. Operations are > classified as "may_use_obj_data" similar to how op->may_{write,read,cache} work. > > The implicit UNSUB is implemented by prepending an UNSTUB operation to the > incoming OP list if "may_use_obj_data() and stub_state == REMOTE". > This sadly causes a waring in the client saying that > the reply doesn't match the request. He is of course right, but I found > it to be the simplest way to try that feature. > > External storage in the prototype is just simple HTTP: PUT on STUB; > GET+DELETE on UNSTUB. > > The Operations implement a kind of converter: STUB reads from the > primary OSD, store the object on the remote and then issue TRUNCATE(0) > and SETXATTR OPs. Similar UNSTUB retrieves the object, then does > WRITEFULL and RMXATTR. > > > ~marcel > > -- > Marcel Lauhoff > Mail/XMPP: ml@xxxxxxxx > http://irq0.org > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -----BEGIN PGP SIGNATURE----- Version: Mailvelope v0.13.1 Comment: https://www.mailvelope.com wsFcBAEBCAAQBQJVZfK8CRDmVDuy+mK58QAAQUAP/jCje1UlnbYJYlLc2aLC OkXBPRTQH1+kza7uloibEpZLaaQpJ3IP+ttBjzbUz3w4DC6Gh31nJgWzidFL qji/b9qIRNBRquypR575K17PtK2xuudFnIObcaGCgmQ36XHcMqjFZYON6I4Q wE+kptkFCbSzo+5JBZsJwsjrQNpVMonSxaSZ08WNamslIWhKuLpFfWF49YyW Aq9YiSehXxiWpUU880FyDY/WNLqflWrWUSXXt+T/cYzzGb9BXAH4jEJl2Dtn QIothZZeabDs+QpF9dxL3teOlHhcqHjPdPOK102/67E+hZz91PTVzf5r3Egs B2OEL3AbjsYk3A5EZK5rxxd4Judc+glDYKq4H+wVFhVFiuBrcv/UsIFx/ZHH 9nJijKQFu/JKJzrkl0ubZDZodXSyR7h+dBUnPwiKNZvBWqwR5BaYJepEl82H hTr3GslhLg1MpaMGqST7yOtR7BxZTb4+U5LhCUZXW5JFvjkNM0kS8VgtnkPP OsPLETq8kTAsnxCzbRtwFIZSW0236Rf2z9naazbgmaZW/uwjlz2rWaxSw8zA +uYBo6dEO7GhhUPrgJW/EiVkqEpwXRqd2hYSeiD63Bz8/efxSExAaoFgHPRt fDRJKHheDmzzYRtOHX21QTV6Lnw9hpjdmC27WAmEfvTNCmLWrzXeF4SS/g1g 3/+W =7BjB -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
