Stan wrote:
 
> I was just reading the new SMUG book (which now seems to have disappeared
> from my desk...hot material!), and found a section that discussed how
> many extents a file can have.  I wasn't willing to accept the "conjecture"
> made by the person they referenced (me) so I thought I'd do a test...
>
> I started a test program yesterday, that loops:
>
>    fopen (file, append)         (the file's reccord size is 4096 bytes)
>    fwrite
>    fclose (fid, %20, 0)         (close, release extra space (if any),
>                                  without changing the LIMIT)
>
> Each iteration allocates another extent.
>
> It's now about 24 hours later, and the file has 110,731 extents,
> and is continuing to grow (about 1 extent per second):
>
There is no limit on how many extents a file can have based on the
file label extent data structure.
 
However, since extents much be in the multiple of pages (4 KB or 16
sectors) and the maximum file size is 4 GB (for now), the maximum
number of extents for a file in the worse case is 4 GB/ 4 KB = 1 mega
extents.  Please note 1 mega extents is more than 1 million extents.
 
Depends on how many files already opened on the system, mapping in this
huge file might cause virtual space manager to run out of extent B-tree
entries though!
 
Paul Wang                        (408) 988-7378
SolutionSoft Systems, Inc.       [log in to unmask]