MySQL and Linux/Unix  /  Other Unix Notes  /  SCO UNIX and OpenServer 5.0.x Notes

7.8 SCO UNIX and OpenServer 5.0.x Notes

The current port is tested only on sco3.2v5.0.5, sco3.2v5.0.6, and sco3.2v5.0.7 systems. There has also been progress on a port to sco3.2v4.2. Open Server 5.0.8 (Legend) has native threads and permits files greater than 2GB. The current maximum file size is 2GB.

We have been able to compile MySQL with the following configure command on OpenServer with gcc 2.95.3.

./configure --prefix=/usr/local/mysql \
    --enable-thread-safe-client --with-innodb \
    --with-openssl --with-vio --with-extra-charsets=complex

gcc is available at

This development system requires the OpenServer Execution Environment Supplement oss646B on OpenServer 5.0.6 and oss656B and the OpenSource libraries found in gwxlibs. All OpenSource tools are in the opensrc directory. They are available at

Use the latest production release of MySQL.

SCO provides operating system patches at for OpenServer 5.0.[0-6] and for OpenServer 5.0.7.

SCO provides information about security fixes at for OpenServer 5.0.x.

The maximum file size on an OpenServer 5.0.x system is 2GB.

The total memory which can be allocated for streams buffers, clists, and lock records cannot exceed 60MB on OpenServer 5.0.x.

Streams buffers are allocated in units of 4096 byte pages, clists are 70 bytes each, and lock records are 64 bytes each, so:

(NSTRPAGES * 4096) + (NCLIST * 70) + (MAX_FLCKREC * 64) <= 62914560

Follow this procedure to configure the Database Services option. If you are unsure whether an application requires this, see the documentation provided with the application.

  1. Log in as root.

  2. Enable the SUDS driver by editing the /etc/conf/sdevice.d/suds file. Change the N in the second field to a Y.

  3. Use mkdev aio or the Hardware/Kernel Manager to enable support for asynchronous I/O and relink the kernel. To enable users to lock down memory for use with this type of I/O, update the aiomemlock(F) file. This file should be updated to include the names of users that can use AIO and the maximum amounts of memory they can lock down.

  4. Many applications use setuid binaries so that you need to specify only a single user. See the documentation provided with the application to determine whether this is the case for your application.

After you complete this process, reboot the system to create a new kernel incorporating these changes.

By default, the entries in /etc/conf/cf.d/mtune are set as follows:

Value           Default         Min             Max
-----           -------         ---             ---
NBUF            0               24              450000
NHBUF           0               32              524288
NMPBUF          0               12              512
MAX_INODE       0               100             64000
MAX_FILE        0               100             64000
CTBUFSIZE       128             0               256
MAX_PROC        0               50              16000
MAX_REGION      0               500             160000
NCLIST          170             120             16640
MAXUP           100             15              16000
NOFILES         110             60              11000
NHINODE         128             64              8192
NAUTOUP         10              0               60
NGROUPS         8               0               128
BDFLUSHR        30              1               300
MAX_FLCKREC     0               50              16000
PUTBUFSZ        8000            2000            20000
MAXSLICE        100             25              100
ULIMIT          4194303         2048            4194303
* Streams Parameters
NSTREAM         64              1               32768
NSTRPUSH        9               9               9
NMUXLINK        192             1               4096
STRMSGSZ        16384           4096            524288
STRCTLSZ        1024            1024            1024
STRMAXBLK       524288          4096            524288
NSTRPAGES       500             0               8000
STRSPLITFRAC    80              50              100
NLOG            3               3               3
NUMSP           64              1               256
NUMTIM          16              1               8192
NUMTRW          16              1               8192
* Semaphore Parameters
SEMMAP          10              10              8192
SEMMNI          10              10              8192
SEMMNS          60              60              8192
SEMMNU          30              10              8192
SEMMSL          25              25              150
SEMOPM          10              10              1024
SEMUME          10              10              25
SEMVMX          32767           32767           32767
SEMAEM          16384           16384           16384
* Shared Memory Parameters
SHMMAX          524288          131072          2147483647
SHMMIN          1               1               1
SHMMNI          100             100             2000
FILE            0               100             64000
NMOUNT          0               4               256
NPROC           0               50              16000
NREGION         0               500             160000

Set these values as follows:

  • NOFILES should be 4096 or 2048.

  • MAXUP should be 2048.

To make changes to the kernel, use the idtune name parameter command. idtune modifies the /etc/conf/cf.d/stune file for you. For example, to change SEMMS to 200, execute this command as root:

# /etc/conf/bin/idtune SEMMNS 200

Then rebuild and reboot the kernel by issuing this command:

# /etc/conf/bin/idbuild -B && init 6

To tune the system, the proper parameter values to use depend on the number of users accessing the application or database and size the of the database (that is, the used buffer pool). The following kernel parameters can be set with idtune:

  • SHMMAX (recommended setting: 128MB) and SHMSEG (recommended setting: 15). These parameters have an influence on the MySQL database engine to create user buffer pools.

  • NOFILES and MAXUP should be set to at least 2048.

  • MAXPROC should be set to at least 3000/4000 (depends on number of users) or more.

  • The following formulas are recommended to calculate values for SEMMSL, SEMMNS, and SEMMNU:

    SEMMSL = 13

    13 is what has been found to be the best for both Progress and MySQL.

    SEMMNS = SEMMSL * number of db servers to be run on the system

    Set SEMMNS to the value of SEMMSL multiplied by the number of database servers (maximum) that you are running on the system at one time.


    Set the value of SEMMNU to equal the value of SEMMNS. You could probably set this to 75% of SEMMNS, but this is a conservative estimate.

You need to at least install the SCO OpenServer Linker and Application Development Libraries or the OpenServer Development System to use gcc. You cannot use the GCC Dev system without installing one of these.

You should get the FSU Pthreads package and install it first. This can be found at You can also get a precompiled package from

FSU Pthreads can be compiled with SCO Unix 4.2 with tcpip, or using OpenServer 3.0 or Open Desktop 3.0 (OS 3.0 ODT 3.0) with the SCO Development System installed using a good port of GCC 2.5.x. For ODT or OS 3.0, you need a good port of GCC 2.5.x. There are a lot of problems without a good port. The port for this product requires the SCO Unix Development system. Without it, you are missing the libraries and the linker that is needed. You also need SCO-3.2v4.2-includes.tar.gz. This file contains the changes to the SCO Development include files that are needed to get MySQL to build. You need to replace the existing system include files with these modified header files. They can be obtained from

To build FSU Pthreads on your system, all you should need to do is run GNU make. The Makefile in FSU-threads-3.14.tar.gz is set up to make FSU-threads.

You can run ./configure in the threads/src directory and select the SCO OpenServer option. This command copies Makefile.SCO5 to Makefile. Then run make.

To install in the default /usr/include directory, log in as root, and then cd to the thread/src directory and run make install.

Remember that you must use GNU make to build MySQL.


If you do not start mysqld_safe as root, you should get only the default 110 open files per process. mysqld writes a note about this in the log file.

With SCO 3.2V4.2, you should use FSU Pthreads version 3.14 or newer. The following configure command should work:

./configure \
    --prefix=/usr/local/mysql \
    --with-named-thread-libs="-lgthreads -lsocket -lgen -lgthreads" \

You may have problems with some include files. In this case, you can find new SCO-specific include files at

You should unpack this file in the include directory of your MySQL source tree.

SCO development notes:

  • MySQL should automatically detect FSU Pthreads and link mysqld with -lgthreads -lsocket -lgthreads.

  • The SCO development libraries are re-entrant in FSU Pthreads. SCO claims that its library functions are re-entrant, so they must be re-entrant with FSU Pthreads. FSU Pthreads on OpenServer tries to use the SCO scheme to make re-entrant libraries.

  • FSU Pthreads (at least the version at comes linked with GNU malloc. If you encounter problems with memory usage, make sure that gmalloc.o is included in libgthreads.a and

  • In FSU Pthreads, the following system calls are pthreads-aware: read(), write(), getmsg(), connect(), accept(), select(), and wait().

  • The CSSA-2001-SCO.35.2 (the patch is listed in custom as erg711905-dscr_remap security patch (version 2.0.0)) breaks FSU threads and makes mysqld unstable. You have to remove this one if you want to run mysqld on an OpenServer 5.0.6 machine.

  • If you use SCO OpenServer 5, you may need to recompile FSU pthreads with -DDRAFT7 in CFLAGS. Otherwise, InnoDB may hang at a mysqld startup.

  • SCO provides operating system patches at for OpenServer 5.0.x.

  • SCO provides security fixes and at and for OpenServer 5.0.x.

  • Pre-OSR506 security fixes. Also, the telnetd fix at or as both and with instructions for installing on pre-OSR506 systems.

    It is probably a good idea to install these patches before trying to compile/use MySQL.

Beginning with Legend/OpenServer 6.0.0, there are native threads and no 2GB file size limit.

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