MyISAM
[edit] How large can a MyISAM file grow?
It depends on your operating system constraints. If you need a MyISAM table that is larger than 4GB in size (and your operating system supports large files), the CREATE TABLE statement allows AVG_ROW_LENGTH and MAX_ROWS options.
On Linux 2.2, you can get MyISAM tables larger than 2GB in size by using the Large File Support (LFS) patch for the EXT2 filesystem. On Linux 2.4, patches also exist for ReiserFS to get support for big files (up to 2TB). However, the maximum available file size still depends on several factors, one of them being the filesystem used to store MySQL tables.
Most modern distributions use Kernel 2.4 or higher and use a filesystem which supports large files by default (e.g. ext3). This means that on MOST modern Linux systems, there is no 2G table limit.
You can check the maximum table size for a table with the SHOW TABLE STATUS statement or
with myisamchk -dv tbl_name. If your large table is read-only, you can use myisampack to
compress it. myisampack usually compresses a table by at least 50%, so you can have, in
effect, much bigger tables.
As a reference.