Problem: empty content being served

Please help. I'm just learning about Apache and web applications,
having mostly developed X-based GUI applications, and it has
fallen upon me to get our Web server up.

I am seeing problems serving non-small files (basically, I've
succeeded with files up to 127 bytes, failed with files larger than
261 bytes, and haven't tried anything in between yet) using Apache 2
under RH Enterprise Linux when the file resides on an IBM Rational
MVFS-type filesystem remotely hosted on an HP-UX computer.

The file is served with appropriate headers, including a correct
byte count, but the data portion is null. If I switch to Apache
version 1, everything works fine. If I move the content to a
standard file system, everything works fine. I tried disabling
EnableMMAP in all the <Directory> entries pointing at the MVFS
filesystem, to no avail.

Has anyone else seen anything like this? Does anyone have a
solution or a workaround?

Here is the access_log entry, manually broken into short lines:

127.0.0.1 - - [01/Oct/2004:16:56:09 -0400]
"GET /cowboy/rwurthMainView/img/help.gif HTTP/1.1" 206 261
"http://127.0.0.1:8081/cowboy/rwurthMainView/img/"
"Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030922"

Nothing shows up in the error_log file. Note the 206 code,
contrasted with the 200 code in the actual data below, captured by
the sockspy (http://sockspy.sf.net) logging proxy.

=================================REQUEST========== ======================
16:51:02 GET /cowboy/rwurthMainView/img/help.gif HTTP/1.1
16:51:02 Host: 127.0.0.1:8081
16:51:02 User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4)
Gecko/20030922
16:51:02 Accept:
text/xml,application/xml,application/xhtml+xml,text/html;q=0.
9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.
2,*/*;q=0.1
16:51:02 Accept-Language: en-us,en;q=0.5
16:51:02 Accept-Encoding: gzip,deflate
16:51:02 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
16:51:02 Keep-Alive: 300
16:51:02 Connection: keep-alive
16:51:02 Referer: http://127.0.0.1:8081/cowboy/rwurthMainView/img/
16:51:02 Range: bytes=0-
16:51:02 If-Range: "232-105-ed45bc0"
16:51:02 Cache-Control: max-age=0
16:51:02
16:51:02
======================================REPLY======= =================
16:51:02 HTTP/1.1 206 Partial Content
16:51:02 Date: Fri, 01 Oct 2004 20:51:02 GMT
16:51:02 Server: Apache/2.0.46 (Red Hat)
16:51:02 Last-Modified: Thu, 26 Aug 2004 18:49:27 GMT
16:51:02 ETag: "232-105-ed45bc0"
16:51:02 Accept-Ranges: bytes
16:51:02 Content-Length: 261
16:51:02 Content-Range: bytes 0-260/261
16:51:02 Connection: close
16:51:02 Content-Type: image/gif
16:51:02
16:51:02

Linux and Apache Version info follows:

Linux XXXXX 2.4.21-9.ELsmp #1 SMP Thu Jan 8 17:08:56 EST 2004 i686

AFAIK the Apache version is straight from the RH EL distro, never
locally recompiled.

Server version: Apache/2.0.46
Server built: Nov 12 2003 10:53:55
Server's Module Magic Number: 20020903:4
Architecture: 32-bit
Server compiled with....
-D APACHE_MPM_DIR="server/mpm/prefork"
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses disabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="logs/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_LOCKFILE="logs/accept.lock"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"

Any help is appreciated.
--
Rich Wurth / rwurth@att.net / Rumson, NJ USA

In article <cjkvgs$39k_002@worldnet.att.net>,
rwurth@att.net (R. T. Wurth) writes:

> 261 bytes, and haven't tried anything in between yet) using Apache 2
> under RH Enterprise Linux when the file resides on an IBM Rational
> MVFS-type filesystem remotely hosted on an HP-UX computer.

The part of TFM you need is EnableSendfile. Specifically, turn it off.

--
Nick Kew

In article <8vm132-kl1.ln1@webthing.com>, nick@hugin.webthing.com (Nick
Kew) wrote:
> In article <cjkvgs$39k_002@worldnet.att.net>,
> rwurth@att.net (R. T. Wurth) writes:
>
> > 261 bytes, and haven't tried anything in between yet) using Apache 2
> > under RH Enterprise Linux when the file resides on an IBM Rational
> > MVFS-type filesystem remotely hosted on an HP-UX computer.
>
> The part of TFM you need is EnableSendfile. Specifically, turn it off.
>

Thank you! That worked like a charm. It's a new feature that wasn't
covered in the O'Reilly book.
--
Rich Wurth / rwurth@att.net / Rumson, NJ USA