On Fri, 2 Aug 2002, Albert D. Cahalan wrote:
| Matti Aarnio writes:
|
| > It depends on many things:
| > - Block layer (unsigned long)
| > - Page indexes (unsigned long)
| > - Filesystem format dependent limits
| > - EXT2/EXT3: u32_t FILESYSTEM block index, presuming the EXT2/EXT3
| > is supported only up to 4 kB block sizes, that gives
| > you a very hard limit.. of 16 terabytes (16 * "10^12")
|
| You first hit the triple-indirection limit at 4 TB.
| http://www.cs.uml.edu/~acahalan/linux/ext2.gif
|
| > - ReiserFS: u32_t block indexes presently, u64_t in future;
| > block size ranges ? Max size is limited by the
| > maximum supported file size, likely 2^63, which is
| > roughly 8 * "10^18", or circa 500 000 times larger
| > than EXT2/EXT3 format maximum.
|
| The top 4 st_size bits get stolen, so it's 60-bit sizes.
| You also get the 32-bit block limit at 16 TB.
| -
For a LinuxWorld presentation in August, I have asked each of the
4 journaling filesystems (ext3, reiserfs, JFS, and XFS) what their
filesystem/filesize limits are. Here's what they have told me.
ext3fs reiserfs JFS XFS
max filesize: 16 TB# 1 EB 4 PB$ 8 TB%
max filesystem size: 2 TB 17.6 TB* 4 PB$ 2 TB!
Notes:
#: think sparse files
*: 4 KB blocks
$: 16 TB on 32-bit architectures
%: 4 KB pages
!: block device limit
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