Apache2 slow with protfpd

[Guille <guillermo.marco@xxxxxxxxx>]

I'm using:
- Debian Squeeze
- Server version: Apache/2.2.16 (Debian)
- ProFTPD Version 1.3.3c
- Net2FTP v 0.98

Hi guys i'm currently using a php script (Net2FTP) as a web FTP client. But i'm experiencing some issues when i try to access big files.
I know this is an Apache list but I've already asked in proftpd forums and net2ftp forums and nobody could help me.

When i try to access a big file (1GB or more) from my web server through apache2 directly it works well i get the download start immediately.
When i access a big file connecting to my proftpd server through a normal client like Filezilla i get no problem too, it works as intended.

The problem occurs when i connect through net2ftp script. Connection and file listing it's ok. But when i try to get a big file, is when i get the issue. It takes for e.g 15minutes to serve the net2ftp script client a 500Mb file.
I think the problem is the connection between apache2 and proftpd.

Watching the processes with "top" on my server i get something like this.


top - 17:39:59 up 2 days,  6:44,  3 users,  load average: 0.00, 0.00, 0.00
Tasks: 198 total,   1 running, 197 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.1%us,  0.2%sy,  0.0%ni, 99.6%id,  0.2%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   3504560k total,  3154244k used,   350316k free,    86552k buffers
Swap:  2654792k total,        0k used,  2654792k free,  2718484k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 9129 www-data  20   0 36788 9260 3484 S    1  0.3   0:00.13 apache2
10371 10008     20   0 10348 3260 1928 S    1  0.1   0:00.07 proftpd

While my server is trying to serve the file it also totally blocks the apache2 server. 

I've tried looking for apache2 config, php5 config and proftpd configs. And I'm going mad at this point.

I don't know if there's any option to make apache2 use more memory for php scripts, but i've already edited php config to use more memory on request etc.. I've also checked max execution time, timeouts etc...

Thank you very much all of you in advance.

Best regards,
Guille.