Re: data.tmp: file too big [SOLVED]

On Tue, May 19, 2009 at 4:22 AM, Jakob Hirsch <[email protected]> wrote:
> Hugo Monteiro, 2009-05-19 01:45:
>
>> Adding -D_FILE_OFFSET_BITS=64 to the compilation flags did the trick. I
>> now have a 2.9G data.cdb file. The bad news is that apparently tinydns/the
>> system isn't capable of coping with that volume of information.
>
> With a 2.9G file, you are probably running into the 3G userspace memory
> limit of the Linux kernel's default 3G/1G kernel/userland memory split.
> Unfortunately, you can only change that by recompiling the kernel, but
> 3.5G/0.5G is the most you can get, but I would not recommend that, as it
> could be too less for the kernel and you will run into the same problem
> soon. So I guess you have two options:
> - split your data file and run 2 or more tinydns processes
> - switch over to a 64 bit system

Something else to try, if you really need > 2G cdb file in a 32-bit
environment, might be to change cdb.c to *not* mmap the cdb file.
According to this bit of cdb_init (cdb.c):

 if (fstat(fd,&st) == 0)
    if (st.st_size <= 0xffffffff) {
      x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0);
      if (x + 1) {
        c->size = st.st_size;
        c->map = x;
      }
    }

it won't mmap the file if it's > 4G?