2 is certainly an intriguing option. RADOS isn't really a database engine (even a nosql one), but should be able to serve your needs here. Have you seen the omap api available in librados? It allows you to efficiently store key/value pairs attached to a librados object (uses leveldb on the OSDs to actually handle the key/value mapping). One caveat is that the C api is somewhat less complete than the C++ api. That would be pretty easily remedied if there were demand though. -Sam On Tue, Aug 13, 2013 at 2:01 PM, Nulik Nol <nuliknol@xxxxxxxxx> wrote: > Hi, > I am planning to use Ceph as a database storage for a webmail > client/server application, and I am thinking to store the data as > key/value pair instead of using any RDBMSs, for speed. The webmail > will manage companies, and each company will have many users, users > will end/receive emails and store them in their inboxes, kind of like > Gmail, but per company. The server will be developed in C, client code > in HTML/Javascript and binary client (standalone app) in C++ > So, my question is, how would you recommend me to design the backend ? > > I have thought of these choices: > > 1. Use Ceph as filesystem and BerkeleyDB as the database engine. > Berekley DB uses 2 files per table, so I will have 1 directory per > company and a 2 files per each table, I think there will be no more > than 20 tables in my whole app. Ceph will be used here as a remote > filesystem where BerkeleyDB will do all the data organization. The > RADOS interface of Ceph (to store key/pair values) will be not used, > since Berkeley DB will write and read to the OSDs directly and > Berkeley DB is a key/value pair database. But I have never used a DB > one a remote filesystem not sure if it will work well. Advantages of > this architecture: quick & easy. > Disadvantages: lower performance (overhead in CephFS and BerkeleyDB), > also I will not be able to write plugins for RADOS in C++ to combine > many data modifications in a single call to the server. > > 2. Use librados C api and write all the 'queries' hardcoded in C > specifically for the > application. Since the application is pretty standard and is not > supposed to change > much, I can do this. I would create a RADOS object for each > application object (like for example 'user' record, 'email' record, > 'chat message' record, etc...). > Advantages: high performance. Disadvantages: a bit more to code , > specially the data search functions. > > I am interested in performance, so I am thinking to go for the option > 2, what do you think? Can RADOS fully replace a database engine ? (I > mean, NoSQL engine, like Berkeley for example) > > Will appreciate very much your comments. > TIA > Nulik > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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