This is a discussion on Many consecutive dialups cause too many open file handles and then NW failure - Windows NT ; Hi. I have a very strange problem related to my work computer (Windows 2000). I have a script which needs to do 2000 consecutive dialups, using a modem, and then opening a few network sockets (FTP, ping, etc). This works ...
Hi. I have a very strange problem related to my work computer (Windows
2000). I have a script which needs to do 2000 consecutive dialups, using a
modem, and then opening a few network sockets (FTP, ping, etc).
This works fine at first, but after a random amount of time, the "handles"
count in Task Manager starts to increase. Originally, it starts out at
around 5-6000 handles, and stays there for a while, but then about 100-120
handles are added for each dialup connect/disconnect, and when it reaches
about 39000, the computer starts to malfunction. Closer inspection shows
that the System process is responsible for not closing these new file
handles, and when it has created around 32768 of them, no more new handles
can be created. After this, the System process consumes almost all CPU, and
when inspecting it with the freeware program Process Explorer, I can see
that it does an enormous amount of "IO other"-operations, which hogs all
The strange thing is that it seems that the problem only starts to occur
randomly -- sometimes after maybe 400 iterations of the script has been
run, sometimes when only 100 iterations have been run. But once the open
file handles start to be left after disconnection, manual
dialups/disconnects create new handles which are not subsequently removed.
What could be the cause of this error? Is there a hack to fix it
(increasing the open file handle limit in the System process from ~32768 to
maybe 131072 would solve my problem), or more preferably, is the cause of
this problem known? Google does not give too many matches, only something
about Terminal Server not being able to handle more than 2048 open files in
a single session. Could it be SMB-related?
The thing is, when using dialups, the rest of the NW is unavailable (like
it should be). Windows 2000 is really slow when using this dialup, since it
tries to access the LAN, but is not able to (resulting in very long
"freezes" if you try to do anything, but does not interfer with the dialup
script). When the computer has failed, I get the "ftp: no buffer space is
supported" error when trying to manually FTP/telnet from a new dialup.
M.S. student, CS/CE @ LTH, Lund, Sweden
Libertarian -- Heavy Metal fanatic
email@example.com -- http://www.efd.lth.se/~d00jp