IBBackupService issue : automatic chunk file size and count

[Ömür Ölmez]

Hello,

I am trying to develop auto backup program which has to create 650 MB fit
chunks without know how backup is long in size.

So, I use this code :
for i :=1 to 99 do
IBBackupService1.BackupFile.Add( Format('filename%d = 681574400', [i]) );
//%d to get unique chunk names and 681... is 650 mb.

Before run this code on aprox. 4 MB size test db, I expected only one file
backup. But what I saw was one 4 MB size chunk file and ninety-eight 100
byte chunk file.

Then, I changed my code as below :
IBBackupService1.BackupFile.Add( Format('filename%d = 1048576', [ 1 ]) );
//size is 1 MB to easy see multiple chunks on small size test db.

Again I expected four 1 MB size chunk files before run and what I saw is one
1 MB size chunk file and one 3 MB size chunk file.

So,
1. Should I calculate and set the number of chunk files ? If I should, how
can I guess expected backup size ?
2. Is it some other way to make automatic numbering chunk size with same
size ?

Thanks
Ömür Ölmez