Good to hear. The actual directory will likely be small in size (number of objects). So it sounds like as long as we manage the number of agreements (2-3) per node then we may be okay. Another quick question, I assume there is a programatic call that can be made to trigger replication push for a supplier. True? thanks, Jason ----- Original Message ---- From: Rich Megginson <rmeggins@redhat.com> To: General discussion list for the Fedora Directory server project. <fedora-directory-users@redhat.com> Sent: Tuesday, December 4, 2007 9:12:19 AM Subject: Re: [Fedora-directory-users] multi-master limit Jason Beavers wrote:> Hi all, > > New to FedoraDS. I''m doing some research for an upcoming application> that will require LDAP. > This App will consist of multiple servers (10 or more) in different > geographical locations. > Each server will authenticate against itself and serve its own local > data. > The full LDAP directory needs to be replicated across all servers so > that users can login to any server. > > I''ve read that there is a limit of 4 writable servers in multi-master> replication. Is this a hard limit or a soft (reccomendation) limit?That means 4 is the highest number of masters we''ve tested exhaustively. The protocol supports up to 2^32-2 masters, but you will usually hit a practical limit in the number of replication agreements. Each repl. agreement runs a separate thread, so you will usually be constrained by resources - available RAM, processors, etc.> The application will need to write changes directly to itself on all > serversThe application will write the changes directly to each of the 10 masters?> so that they are immediately available locally, then replicated to > other servers. > > Is this possible with FedoraDS?Yes, it is possible.> > Thanks in advance! > > Beavrz1 > >------------------------------------------------------------------------> Get easy, one-click access to your favorites. Make Yahoo! your > homepage.<http://us.rd.yahoo.com/evt=51443/*http://www.yahoo.com/r/hs>>------------------------------------------------------------------------> > -- > Fedora-directory-users mailing list > Fedora-directory-users@redhat.com > https://www.redhat.com/mailman/listinfo/fedora-directory-users >____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs
Jason Beavers wrote:> Good to hear. The actual directory will likely be small in size > (number of objects).Also important to keep in mind is your update rate - avg. updates per minute, max. updates per minute.> So it sounds like as long as we manage the number of agreements (2-3) > per node then we may be okay. > > Another quick question, I assume there is a programatic call that can > be made to trigger replication push for a supplier. True?In Fedora DS, replication is supplier initiated, and will update as soon as possible by default. That is, as soon as the supplier receives the change, it will send it to the consumer. There are also programmatic ways to do it, but you usually don''t need to.> > thanks, > > Jason > > ----- Original Message ---- > From: Rich Megginson <rmeggins@redhat.com> > To: General discussion list for the Fedora Directory server project. > <fedora-directory-users@redhat.com> > Sent: Tuesday, December 4, 2007 9:12:19 AM > Subject: Re: [Fedora-directory-users] multi-master limit > > Jason Beavers wrote: > > Hi all, > > > > New to FedoraDS. I''m doing some research for an upcoming application > > that will require LDAP. > > This App will consist of multiple servers (10 or more) in different > > geographical locations. > > Each server will authenticate against itself and serve its own local > > data. > > The full LDAP directory needs to be replicated across all servers so > > that users can login to any server. > > > > I''ve read that there is a limit of 4 writable servers in multi-master > > replication. Is this a hard limit or a soft (reccomendation) limit? > That means 4 is the highest number of masters we''ve tested > exhaustively. The protocol supports up to 2^32-2 masters, but you will > usually hit a practical limit in the number of replication agreements. > Each repl. agreement runs a separate thread, so you will usually be > constrained by resources - available RAM, processors, etc. > > The application will need to write changes directly to itself on all > > servers > The application will write the changes directly to each of the 10 masters? > > so that they are immediately available locally, then replicated to > > other servers. > > > > Is this possible with FedoraDS? > Yes, it is possible. > > > > Thanks in advance! > > > > Beavrz1 > > > > ------------------------------------------------------------------------ > > Get easy, one-click access to your favorites. Make Yahoo! your > > homepage. <http://us.rd.yahoo.com/evt=51443/*http://www.yahoo.com/r/hs> > > ------------------------------------------------------------------------ > > > > -- > > Fedora-directory-users mailing list > > Fedora-directory-users@redhat.com > <mailto:Fedora-directory-users@redhat.com> > > https://www.redhat.com/mailman/listinfo/fedora-directory-users > > > > > > ------------------------------------------------------------------------ > Looking for last minute shopping deals? Find them fast with Yahoo! > Search. > <http://us.rd.yahoo.com/evt=51734/*http://tools.search.yahoo.com/newsearch/category.php?category=shopping> > > ------------------------------------------------------------------------ > > -- > Fedora-directory-users mailing list > Fedora-directory-users@redhat.com > https://www.redhat.com/mailman/listinfo/fedora-directory-users >
Enrico M. V. Fasanelli
2007-Dec-05 22:14 UTC
Re: [Fedora-directory-users] multi-master limit
Dear Rich, can you explain with some numbers on that? How much RAM I need per each separate thread? How many replication agreement in a server equipped with 2, 4, 8, 16 GB RAM? How the avg. update rate influence these numbers? And the max update rate? 30 replication agreement per server is a medium value? large? huge? Too much? Out of any hardware configuration? Thank in advance. Ciao, Enrico Rich Megginson wrote:> Also important to keep in mind is your update rate - avg. updates per > minute, max. updates per minute.[...snips...]> In Fedora DS, replication is supplier initiated, and will update as soon > as possible by default. That is, as soon as the supplier receives the > change, it will send it to the consumer. There are also programmatic > ways to do it, but you usually don''t need to.[...snips...]>> That means 4 is the highest number of masters we''ve tested >> exhaustively. The protocol supports up to 2^32-2 masters, but you will >> usually hit a practical limit in the number of replication >> agreements. Each repl. agreement runs a separate thread, so you will >> usually be >> constrained by resources - available RAM, processors, etc.[...snips...]
Enrico M. V. Fasanelli wrote:> > Dear Rich, > > can you explain with some numbers on that?Not really. I don''t have any exact numbers or formulae that you can plug in various parameters such as OS, RAM, CPUs, etc.> > How much RAM I need per each separate thread? How many replication > agreement in a server equipped with 2, 4, 8, 16 GB RAM? > > How the avg. update rate influence these numbers? And the max update > rate?In general, the higher the average update rate, the harder the server is going to have to work to send out updates to all replicas. And a very high update rate for a short period of time may spike the RAM and/or CPU usage.> > 30 replication agreement per server is a medium value? large? huge? > Too much? Out of any hardware configuration?I don''t really have a good answer for any of these questions. I do know that at some point you are going to see a drop off in performance due to thread contention. Adding more RAM and CPUs will mitigate this drop.> > Thank in advance. > > Ciao, > Enrico > > > Rich Megginson wrote: > >> Also important to keep in mind is your update rate - avg. updates per >> minute, max. updates per minute. > > [...snips...] > >> In Fedora DS, replication is supplier initiated, and will update as >> soon as possible by default. That is, as soon as the supplier >> receives the change, it will send it to the consumer. There are also >> programmatic ways to do it, but you usually don''t need to. > > [...snips...] > >>> That means 4 is the highest number of masters we''ve tested >>> exhaustively. The protocol supports up to 2^32-2 masters, but you will >>> usually hit a practical limit in the number of replication >>> agreements. Each repl. agreement runs a separate thread, so you >>> will usually be >>> constrained by resources - available RAM, processors, etc. > > [...snips...] > > > > ------------------------------------------------------------------------ > > -- > Fedora-directory-users mailing list > Fedora-directory-users@redhat.com > https://www.redhat.com/mailman/listinfo/fedora-directory-users >