Bigfile Tablespace Basics
Using bigfile tablespaces with a block size of 32K, a datafile can be as large as 128 terabytes,
with a maximum database size of 8 exabytes (EB). In contrast, a database using only smallfile
tablespaces can have a maximum datafile size of 128 gigabytes (GB) and therefore a maximum
database size of 8 petabytes (PB). Because a bigfile tablespace can only have one datafile, you
never need to decide whether to add a datafile or autoextend the single datafile for the tablespace.
If you are using ASM and OMF, you won??™t even need to know the name of the single datafile.
Given that the maximum number of datafiles in a database on most platforms is 65,533, and
the number of blocks in a bigfile tablespace datafile is 232, you can calculate the maximum amount
of space (M) in a single Oracle database as the maximum number of datafiles (D) multiplied by the
maximum number of blocks per datafile (F) multiplied by the tablespace block size (B):
M = D * F * B
Therefore, the maximum database size, given the maximum block size and the maximum number
of datafiles, is
65,533 datafiles * 4,294,967,296 blocks per datafile * 32,768 block size =
9,223,231,299,366,420,480 = 8EB
For a smallfile tablespace, the number of blocks in a smallfile tablespace datafile is only 222.
Therefore, our calculation yields
65,535 datafiles * 4,194,304 blocks per datafile * 32,768 block size =
9,007,061,815,787,520 = 8PB
In Table 16-1, you can see a comparison of maximum datafile sizes for smallfile tablespaces
and bigfile tablespaces given the tablespace block size.
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