Depend on Operating System

If the operating system or file system places a limit on the number of files in a directory, MySQL is bound by thatconstraint.The efficiency of the operating system in handling large numbers offiles in a directory can place a practical limit on the number of tables in a database.
If the time required to open a file in the directory increases significantly as the number of files increases, database performance can be adversely affected.The amount of available disk space limits the number of tables.MySQL3.22 had a 4GB (4 gigabyte) limit on table size.

With the MyISAM storage engine in MySQL 3.23, the maximum table size was increased to65536 terabytes (2567 – 1 bytes). With this larger allowed table size,the maximum effective table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits.

The InnoDB storage engine maintains InnoDB tables within a table space that can be created from several files. This allows a table to exceed the maximum individual file size.

The table space can include raw disk partitions, which allows extremely large tables. The maximum table space size is 64TB.The following table lists some examples of operating system file-size limits. This is only a rough guide and is not intended to be definitive.For the most up-to-date information, be sure to check the documentationspecific to your operating system.

Operating System File-size Limit Linux 2.2-Intel 32-bit 2GB (LFS: 4GB)Linux 2.4+ (using ext3 filesystem) 4TBSolaris 9/10 16TBNetWare w/NSS filesystem 8TBWin32 w/ FAT/FAT32 2GB/4GBWin32 w/ NTFS 2TB (possibly larger)MacOS X w/ HFS+ 2TB