Re: [ZODB-Dev] Plone in P2P using Zope over DHT
Hi guys, It's looking like Plone/ZODB would need too much modification and testing at the current time to move in to P2P. The most promising environment in our research so far are frameworks built on the Squeak language which is used by the OpenCobalt project (a P2P collaborative 3D world). Thanks for all your feedback and advice, and happy new year :-) Aran ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Aran Dunkley wrote: Hi guys, It's looking like Plone/ZODB would need too much modification and testing at the current time to move in to P2P. Neither Plone nor ZODB require modifications. You need a cloud-aware storage suitable to be used as ZODB storage. - -aj The most promising environment in our research so far are frameworks built on the Squeak language which is used by the OpenCobalt project (a P2P collaborative 3D world). Thanks for all your feedback and advice, and happy new year :-) Aran ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev - -- ZOPYX Limited | zopyx group Charlottenstr. 37/1 | The full-service network for Zope Plone D-72070 Tübingen| Produce Publish www.zopyx.com | www.produce-and-publish.com - E-Publishing, Python, Zope Plone development, Consulting -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQGUBAEBAgAGBQJNJi3GAAoJEADcfz7u4AZjNEsLv1afSBaHjYhQ5RqvcRuKOMXD FVs/E6C/icI7FlzZmOAxKGT0PpDclT2mnfF7MuHBJJq1ITHI/wwVx4TCvDQeqJUZ gIloUzzxp5S1JcNQLYuLJQewqIzfgpXE5spATEtv79GP/fYcEFeOCvcFyCUOxFb6 wIIhSokCoQhBDRiQPmZUIXEaBg2sjQ/kX0FEZzVnF1muuQpEHBOpASV9m9SbLKIr rhScpv4DHdDggITRuQBAykYsIwqrbNA+DLL7MEAVmKCqmDZ2d+1m0ShtZeopiaDr Twtz0LgpSI86NLeNoXgu1YGELZL6XGVqLqFhDWFZaWJwukZ/dq2UHGVUudxJ3yg6 N6TBsjEN9mXWp44rTFa8/odqPyJeMxEsLv79w0SaMF7HKV3jlWzuTQsdWu0IjKC5 N4Pmw2YiQk8mq3NGM2cP8aL6GYr8mGXwyVg7kGdKbSdnIDsGjvUZK6nlWiMiWT3z aiLvdR8vtzl9GUxy6qVSOSHWPVqmqgs= =m2nt -END PGP SIGNATURE- attachment: lists.vcf___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
Thanks for the feedback Vincent :-) it sounds like NEO is pretty close to being SQL-free. As one of the NEO team, what are your thoughts on the practicality of running Plone in a P2P environment with the latencies experienced in standard DHT (such as for example those based on Kademlia) implemtations? On 04/01/11 22:27, Vincent Pelletier wrote: Hi. Le mardi 4 janvier 2011 07:18:34, Aran Dunkley a écrit : The problem is that it uses SQL for its indexing queries (they quote NoSQL as meaning Not only SQL). SQL cannot work in P2P space, but can be made to work on server-clusters. Yes, we use MySQL, and it bites us on both worlds actually: - in relational world, we irritate developers as we ask questions like why does InnoDB load a whole row when we just select primary key columns, which ends up with don't store blobs in mysql - in key-value world, because NoSQL using MySQL doesn't look consistent So, why do we use MySQL in NEO ? We use InnoDB as an efficient BTree implementation, which handles persistence. We use MySQL as a handy data definition language (NEO is still evolving, we need an easy way to tweak table structure when a new feature requires it), but we don't need any transactional isolation (each MySQL process used for NEO is accessed by only one process through one connection). We want to stop using MySQL InnoDB in favour of leaner-and-meaner back-ends. I would especially like to try kyoto cabinet[1] in on-disk BTree mode, but it requires more work than the existing MySQL adaptor and there are more urgent tasks in NEO. Just as a proof-of-concept, NEO can use a Python BTree implementation as an alternative (RAM-only) storage back-end. We use ZODB's BTree implementation, which might look surprising as it's designed to be stored in a ZODB... But they work just as well in-RAM, and that's all I needed for such proof-of- concept. [1] http://fallabs.com/kyotocabinet/ Regards, ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
Am 04.01.2011, 12:40 Uhr, schrieb Aran Dunkley a...@organicdesign.co.nz: Thanks for the feedback Vincent :-) it sounds like NEO is pretty close to being SQL-free. As one of the NEO team, what are your thoughts on the practicality of running Plone in a P2P environment with the latencies experienced in standard DHT (such as for example those based on Kademlia) implemtations? Something which may be worthwhile and give you an impression what the storage backend does for a common operation would be to instrument the ZODB code a bit. Just look at the current FileStorage and add a few log()s into its load/store methods. Maybe there are other methods of interest, too. Hooking this shouldn't take long. Then I suggest you generate (or maybe you already have) a well-sized plone to test on. Perform a typical request on a site and see what the storage is doing. This will give you a solid idea what the storage has to do. My guess (and I mostly infer this from the zodb code I've looked at) is that you can get many storage read requests for something like searching the catalog. I guess this will happen, because you get a load() call for each BTree bucket that you are traversing. Maybe I am totally wrong of course :) However, instrumenting the storage will show. You might also find there are certain hotspots (like the catalog). Depending on their size you could make your users download these completely from the cloud before being able to use them. This would reduce the number of small randomly-seeking requests a lot. Another thing you need to consider is implementing the transaction functionality. I'm not sure how to do something like this in the cloud or even if it's possible at all (given certain performance limitations). And finally, my experiences using P2P is that it takes a while to build up speed for a certain download. And client uplinks are not as fast your typical web server's uplink. Also firewalls seem to cause problems sometimes (maybe workable with NAT punching?). Maybe all of this is feasible in your situation, but this depends heavily on your requirements, usage and goals. Doing some fast prototyping and contacting authors who already wrote papers (or better implementations) is probably the best way to get solid a solid idea. -Matthias ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
I'm not very optimistic about this I'm afraid. First the problems with using Plone: * Plone relies heavily on its in ZODB indexes of all content (portal_catalog). This means that every edit will change lots of objects (without versioning ~15-20, most of which are in the catalogue). * At least with archetypes a content object's data is spread over multiple objects. (This should be better with Dexterity, though you will still have multiple objects for locking and workflow) * If you use versioning you'll see ~ 100 objects changed in an edit. * Even loading the front-page will take a long time - In my experiments writing an amazon s3 backend for ZODB the extra latency of fetching each object was really noticeable. But I'm not sure even a simpler ZODB CMS would be a good fit for a p2p DHT: * ZODB is transactional using two phase commit. With p2p latencies, these commits will be horribly slow - all clients storing changed objects would need to participate in the transaction. * Each client's object cache will need to know about invalidations, I don't see any way of supplying these from a DHT. I expect you'd have more success storing content items as single content objects / pages in the DHT and then generating indexes based on that. You'll need some way of storing parent - child relationships between the content objects too, as updating a single list of children object will be incredibly difficult to get right in a distributed system. Laurence On 4 January 2011 11:40, Aran Dunkley a...@organicdesign.co.nz wrote: Thanks for the feedback Vincent :-) it sounds like NEO is pretty close to being SQL-free. As one of the NEO team, what are your thoughts on the practicality of running Plone in a P2P environment with the latencies experienced in standard DHT (such as for example those based on Kademlia) implemtations? On 04/01/11 22:27, Vincent Pelletier wrote: Hi. Le mardi 4 janvier 2011 07:18:34, Aran Dunkley a écrit : The problem is that it uses SQL for its indexing queries (they quote NoSQL as meaning Not only SQL). SQL cannot work in P2P space, but can be made to work on server-clusters. Yes, we use MySQL, and it bites us on both worlds actually: - in relational world, we irritate developers as we ask questions like why does InnoDB load a whole row when we just select primary key columns, which ends up with don't store blobs in mysql - in key-value world, because NoSQL using MySQL doesn't look consistent So, why do we use MySQL in NEO ? We use InnoDB as an efficient BTree implementation, which handles persistence. We use MySQL as a handy data definition language (NEO is still evolving, we need an easy way to tweak table structure when a new feature requires it), but we don't need any transactional isolation (each MySQL process used for NEO is accessed by only one process through one connection). We want to stop using MySQL InnoDB in favour of leaner-and-meaner back-ends. I would especially like to try kyoto cabinet[1] in on-disk BTree mode, but it requires more work than the existing MySQL adaptor and there are more urgent tasks in NEO. Just as a proof-of-concept, NEO can use a Python BTree implementation as an alternative (RAM-only) storage back-end. We use ZODB's BTree implementation, which might look surprising as it's designed to be stored in a ZODB... But they work just as well in-RAM, and that's all I needed for such proof-of- concept. [1] http://fallabs.com/kyotocabinet/ Regards, ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - zodb-...@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Aran Dunkley wrote: I'm wondering what you guys, the core developers, think of the practicalities of Plone in P2P, for example could ZODB use a DHT as its storage layer? what kind of querying is required on the DHT? No idea what P2P means to you in particular. The ZODB is a mandatory requirement for Plone as storage layer. You may work on storage layer implementation for the ZODB fulfilling your requirements (similar to Relstorage implementing a RDBMS backend for the ZODB). I have strong doubts that a P2P or (cloud-ish) backend is feasible as the ZODB is ACID compatible and ACID is basically something you can not achieve in the cloud or better spoken in a highly distributed environment. - -aj - -- ZOPYX Limited | zopyx group Charlottenstr. 37/1 | The full-service network for Zope Plone D-72070 Tübingen| Produce Publish www.zopyx.com | www.produce-and-publish.com - E-Publishing, Python, Zope Plone development, Consulting -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQGUBAEBAgAGBQJNIrFoAAoJEADcfz7u4AZjK7ELwKXWquWP4BuqEq5BNivjEQOy F5FQZNSzTHtNlSLOjFNbQetcXm7ESRAUw/7Vu2o8Ds4a+J8KUMM8VkRVqr0I8oqm EbjlDpD9m+tIWQXH5YhKP75r/QzjZ9iT1XrnZIH5q3nFyY48zCpJs1yrCGcIYORd xJasPTjcWshArzT6lTu4XRnPNIZmyvw5JgW3LDu3SrlFOLj+NRY+wqVlXAk52SNK YxwMvEn9LfKA6yL20uhUk7KkYeoQP0OZeQISV33SVjKLEMKU0UQYZTABfrcfmJgp hlMiU652JUsn1VcQD+6w9TXJ0dOLpBgVWtuE8sIxviSZIu57UIbUdGOIEuNTXAt/ Mlnvp6W9gXGPLY7iU8QAeWZpPa4j+Nal+kFqVJo98ZI0I4dTo/cLd9H6OcECNbUF LLsUHYE6uI/uOKlavM+uKLERBtoleKNYxu0EaF/ZtXSvGwiSQv1Wp+s6TgHoGLBR Mq2THaTGogmHUOlAvJ7drk2oJP5UpYo= =nQC8 -END PGP SIGNATURE- attachment: lists.vcf___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
I mean P2P as in using a DHT (distributed hash table) for its storage layer so that it can run in a network composed only of the client users with no web-server, the same way that the file-sharing programs such as azzureus and aMule work. We can develop a basic wiki/blog in this way, but would prefer a mature CMS like Plone. On 04/01/11 18:34, Andreas Jung wrote: Aran Dunkley wrote: I'm wondering what you guys, the core developers, think of the practicalities of Plone in P2P, for example could ZODB use a DHT as its storage layer? what kind of querying is required on the DHT? No idea what P2P means to you in particular. The ZODB is a mandatory requirement for Plone as storage layer. You may work on storage layer implementation for the ZODB fulfilling your requirements (similar to Relstorage implementing a RDBMS backend for the ZODB). I have strong doubts that a P2P or (cloud-ish) backend is feasible as the ZODB is ACID compatible and ACID is basically something you can not achieve in the cloud or better spoken in a highly distributed environment. -aj ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
Hey Andreas, I don't know much about Aran's project, so you are right to wonder the necessity to have yet another storage backend. Maybe he has needs and requirements that can't be fulfilled by the current backends. Aran, can you fill us in a little on the necessity of having a DHT ? What are the requirements you're trying to fulfill for your project ? Cheers -Marc @mastachand http://linkd.in/heve30 On Jan 3, 2011, at 11:06 PM, Andreas Jung wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Marc Villemade wrote: Hey Andreas, I think it makes sense if the storage backend is hosted on-premise (hence private cloud), and i think that's what Aran is thinking about. They could have Plone-ZODB-Storage backend in the same datacenter, hence no latency problem and good network throughput, provided that the cloud storage used is capable of offering high performance. First you should bring up arguments why the existing backends like ZEO, Relstorage or NEO are not good enough in your case. Looking at the development history of Relstorage or NEO: implementing an enterprise-level storage for the ZODB seems to be hard and time-consuming (and expensive). - -aj -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQGUBAEBAgAGBQJNIsbnAAoJEADcfz7u4AZjcesLwMPmfuPkHoTWGOFHJ5SdUmQZ cYBpUmNjX6X1uDfoUC+oDQvXBJHQ0Us5kSk2u0KBhReBXF6oiLWT/zpB1EO7VgrJ IxaWXnVr5c/mFWGdyHq1ok0Mmyu0eprQ7sVc4pxhUi6V/1fpC6+W8yv1zpukCWIa ErBbozqSCoJ3XRgrlrl0ppwHeutVeOQsqMZmeq3mJ4OlfqDmjVfD5qupdAUybVDY mtKcEJPnvmyPM9ftKgr2yUULkit5knnH4xtbZHvk/kGgk/r3k4zEEi20TXtmn1/2 Anjr3/GT54LvzZWb5qYcmnBbhmcERJulNjN7aWTJDXNH1QfaLuuI6afBH0iLAxjv o9jM8mWxFvjsob2QVRgC7uGSFesebXc/bhdl0oPWyJ2hX3jY5vwkbFt6XVDmvkdY OZOJiCcX2SLUhzmc669De2TCaTcl6szPhw0ZsHfZcwNLSusH276O4pFDoxxrKCAU pT1gKXVBNbX+m4ligYGBLRx+n++lrTg= =dOSV -END PGP SIGNATURE- lists.vcf ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
I have looked at NEO which is the closest thing I've found to the answer, in fact NEO is why I felt Plone was the best choice of CMS to inquire further about The problem is that it uses SQL for its indexing queries (they quote NoSQL as meaning Not only SQL). SQL cannot work in P2P space, but can be made to work on server-clusters. We intend not to have any machines in our network other than the users computers running the P2P application. So we would need to know exactly what kinds of querying ZODB expects to be available in its interface to the storage layer. DHT's can be slow for the first read but cache locally after that. On 04/01/11 20:06, Andreas Jung wrote: Marc Villemade wrote: Hey Andreas, I think it makes sense if the storage backend is hosted on-premise (hence private cloud), and i think that's what Aran is thinking about. They could have Plone-ZODB-Storage backend in the same datacenter, hence no latency problem and good network throughput, provided that the cloud storage used is capable of offering high performance. First you should bring up arguments why the existing backends like ZEO, Relstorage or NEO are not good enough in your case. Looking at the development history of Relstorage or NEO: implementing an enterprise-level storage for the ZODB seems to be hard and time-consuming (and expensive). -aj ___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
Re: [ZODB-Dev] Plone in P2P using Zope over DHT
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Marc Villemade wrote: Hey Andreas, I don't know much about Aran's project, so you are right to wonder the necessity to have yet another storage backend. Maybe he has needs and requirements that can't be fulfilled by the current backends. That's exactly the point: put the requirements on the desk and check each of the existing storage backends against the requirements. Then make a decision whether you really need a new storage implementation or if there is a chance for using an existing solution (or providing funding for feature extensions) or starting with a complete a new project (taking possibly a long time (years) for becoming mature enough for production). - -aj -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQGUBAEBAgAGBQJNIspNAAoJEADcfz7u4AZjeqYLvi1UECuf5Zxp8JlrP51IDWtY m4pNJzXJyAHKE/U0yFH2hcjJpVWZUQytu9XgiQj9ZASMgL/OLRIurl1O3RC4u5lc yzq4qIKVR8oP2XAuTNpsq6jvAFgkoeLvxxLtks5L/YSxz9W/9+Gvm6zLFxjCVLde L+H+vVViRUpdF9EeKp9TbSNVALIxs3lx5qREFoFsOhq43Potl7c846GGzwD/NKTb W2++9WAlSh6vOPDBMMyDquO+MABehqLSOE6sQ297ZvcU9NJ2AtIzcr8IiHD6jSpA Jft9yhAGqVt/oljUdTtNKayNxqJDWDSKNEI58q62TO6VMIa8xOTfVqxrWjnh4TOU QfBHGxfPiGKVFaonCvBO+aQ72dlKhwR8t7yU4f3II99xeMYmUPNAEmJZcdkkd5M3 cuovoIDJSJVuwAPe/QI1h7oDqL7iIE2ZAMXL3T8g5LyXFp1NtvMsUc2gm6u3TgFL va2S4Zb7axxB/2PiYeLZrJtyv1a3A6w= =kf64 -END PGP SIGNATURE- attachment: lists.vcf___ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
