How many blogs does the centrel database can hold?

I have a blog site which contains around 7 lakh blogs.
I am converting this blog site to wordpress multisite.So i need to migrate all table datas into wordpress database table format.
I have two database servers.I am planning to create 4096 database(2048 database in one server and 2048 in another server). Central database will be in first server.
When i migrate the table data to wordpress database format,each blog will have 9 tables.therefore for 7 lakh blog,there will be (7 lakh*9)tables.

So my question is,how many blogs does the cental database can hold?

    Timothy Bowers

    Hey there.

    The restriction would be that of MySQL and your server hardware really.

    MySQL themselves don't limit the number of tables or databases, your host or system admin may have limited them though.

    http://dev.mysql.com/doc/refman/5.5/en/database-count-limit.html

    The storage engine as you see there may have some limits, InnoDB has a limit of 4 billion tables. That's a heck of a lot of sites going on there.

    The less running on a database (being processed) the quicker it will run, and that's the same for the server too.

    So are you doing a manual migration?

    If you're importing multiple WordPress blogs into a multisite would a plugin like our Snapshot not help you out here:

    https://premium.wpmudev.org/project/snapshot/

    That should save some heavy lifting and get blogs imported into the network much quicker.

    Hope this helps, have a great weekend!

    Take care.

    Taylor

    Thanks Timothy Bowers for your quick reply

    Actually my plan was
    First migrate 20,000 blogs to central database
    Then Apply multidb plugin
    move next 20,000 blogs to central database
    Apply multidb plugin
    --------
    Process continues till all blogs(7 lakh) migrates..

    This process is time consuming and risky.

    Now i think,First move all the blogs(7 lakh) to central database and apply multidb plugin.
    So can i proceed with this process? Does multi db plugin is capable of splitting this tables(7lakh *9) into different database servers?
    Is there any restriction to apply multidb plugin?

    Jack Kitterhing

    Hi there @Taylor,

    Hope you're well today.

    Mutli-DB will split the tables for one site across multiple databases, but it's entirely random, there isn't a set process as such. So you couldn't say for sure, that one table from each would be in each database if that makes sense?

    The only way you could do that is, if each blog had it's own VIP database, but that would be too many databases.

    It's also worth noting that Mutli-DB isn't suitable for shared hosts, Ideally you should have a VPS or dedicated server with root access.

    Most shared hosts don't offer the database size needed or the correct MySQL permissions.

    Thank you!

    Kind Regards
    Jack.