Re: RE: Raw device with Suse Linux Enterpise 10 an

Alexey, > To summarize the discussion, I'd suggest the following: > For production system, use RAW devices with Informix, but > reference them through symbolic links. I did just that (SLES 10 SP1), but to my great surprise had to discover that these symbolic links didn't survive a reboot. This is a significant change from our previously used SuSE 7.2, where this wasn't a problem. It seems that since the raw devices do not survive a reboot and have to be newly created by the script /etc/init.d/raw, symbolic links to these devices that reside under /dev are also deleted. I haven't tried yet if it makes a difference when these links do not reside under /dev. Are there any general recommendations about where these symbolic links should be put? I can probably write my own startup script that creates these symbolic links and takes care of the proper permissions etc., but I'd appreciate if anybody could post an already tested solution. Regards, Richard

RICHARD SPITZ wrote: > Alexey, > > >> To summarize the discussion, I'd suggest the following: >> For production system, use RAW devices with Informix, but >> reference them through symbolic links. >> > > I did just that (SLES 10 SP1), but to my great surprise had to discover that > these symbolic links didn't survive a reboot. This is a significant change > from our previously used SuSE 7.2, where this wasn't a problem. > > It seems that since the raw devices do not survive a reboot and have to be > newly created by the script /etc/init.d/raw, symbolic links to these devices > that reside under /dev are also deleted. > > I haven't tried yet if it makes a difference when these links do not reside > under /dev. Are there any general recommendations about where these symbolic > links should be put? > It's typical to create the links that Informix uses in the informix user's home directory tree often in a subdirectory named disk, chunks, or similar. This is preferred to using /dev as normally only an SA can add or maintain links in /dev and often DBAs are not given, nor do we typically want, root priveleges. It is also preferred over placing the 'disk' links directory under $INFORMIXDIR to avoid problems if and when you upgrade as upgrades should be installed into a new INFORMIXDIR leaving the previous version alone. Don't know if SuSE will leave those links alone of if they need to be recreated, but if they do, make sure that user informix can modify the script called from init.d/raw so new links can be added by informix when new chunks are initially linked. Art S. Kagel > I can probably write my own startup script that creates these symbolic links > and takes care of the proper permissions etc., but I'd appreciate if anybody > could post an already tested solution. > > Regards, Richard ================================================================================ =========== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.oninit.com/home/disclaimer.php ================================================================================ ===========

I have seen this happen, it's a bit of a pain. We don't symbolically link under the dev system which helps. Also be careful of the owner and group permissions on the raw devices, they revert to root. -----Original Message----- From: RICHARD SPITZ [mailto:richard.spitz@med.uni-muenchen.de] Sent: 05 February 2008 11:40 To: ids@iiug.org Subject: Re: RE: Raw device with Suse Linux Enterpise 10 an [11159] Alexey, > To summarize the discussion, I'd suggest the following: > For production system, use RAW devices with Informix, but reference > them through symbolic links. I did just that (SLES 10 SP1), but to my great surprise had to discover that these symbolic links didn't survive a reboot. This is a significant change from our previously used SuSE 7.2, where this wasn't a problem. It seems that since the raw devices do not survive a reboot and have to be newly created by the script /etc/init.d/raw, symbolic links to these devices that reside under /dev are also deleted. I haven't tried yet if it makes a difference when these links do not reside under /dev. Are there any general recommendations about where these symbolic links should be put? I can probably write my own startup script that creates these symbolic links and takes care of the proper permissions etc., but I'd appreciate if anybody could post an already tested solution. Regards, Richard ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum. See you at the IIUG Informix 2008 Conference The Power Conference for Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas City), Kansas http://www.iiug.org/conf Registration Now Open!! ________________________________________________________________________ This email has been scanned for all viruses by the MessageLabs Email Security System before entering the GFM Network. If you have any queries please contact Systems Administration or IT. ________________________________________________________________________ ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________

If it's the Linux 2.6 kernel, /dev gets rebuilt on every reboot. Like Art suggests, create your links somewhere else. Also (at least on RedHat) raw devices must be specified in a file under /etc/udev/rules.d/ Once that is done, the /etc/sysconfig/rawdevices file works fine. Bob Roussey Unix / Informix Administration Spirit Airlines Robert.Roussey@SpiritAir.com -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art S. Kagel (Oninit LLC) Sent: Tuesday, February 05, 2008 6:50 AM To: ids@iiug.org Subject: Re: Raw device with Suse Linux Enterpise 10 an [11160] RICHARD SPITZ wrote: > Alexey, > > >> To summarize the discussion, I'd suggest the following: >> For production system, use RAW devices with Informix, but >> reference them through symbolic links. >> > > I did just that (SLES 10 SP1), but to my great surprise had to discover that > these symbolic links didn't survive a reboot. This is a significant change > from our previously used SuSE 7.2, where this wasn't a problem. > > It seems that since the raw devices do not survive a reboot and have to be > newly created by the script /etc/init.d/raw, symbolic links to these devices > that reside under /dev are also deleted. > > I haven't tried yet if it makes a difference when these links do not reside > under /dev. Are there any general recommendations about where these symbolic > links should be put? > It's typical to create the links that Informix uses in the informix user's home directory tree often in a subdirectory named disk, chunks, or similar. This is preferred to using /dev as normally only an SA can add or maintain links in /dev and often DBAs are not given, nor do we typically want, root priveleges. It is also preferred over placing the 'disk' links directory under $INFORMIXDIR to avoid problems if and when you upgrade as upgrades should be installed into a new INFORMIXDIR leaving the previous version alone. Don't know if SuSE will leave those links alone of if they need to be recreated, but if they do, make sure that user informix can modify the script called from init.d/raw so new links can be added by informix when new chunks are initially linked. Art S. Kagel > I can probably write my own startup script that creates these symbolic links > and takes care of the proper permissions etc., but I'd appreciate if anybody > could post an already tested solution. > > Regards, Richard ======================================================================== =================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.oninit.com/home/disclaimer.php ======================================================================== =================== ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum. See you at the IIUG Informix 2008 Conference The Power Conference for Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas City), Kansas http://www.iiug.org/conf Registration Now Open!!

Hi, Richard, There is no need to keep symbolic links to raw devices under /dev. I usually keep them under /data/informix_data Unlike links under /dev, these links do not disappear after reboot :-) Also, with both Suse and RedHat it is necessary to create a custom script to re-create raw devices after reboot and give them proper permission (660, informix:informix) On RedHat, a standard method to preserve raw devices after reboot is to include them into /etc/sysconfig/rawdevices; startup script /etc/rc3.d/S56rawdevices (that uses this config file to create raw devices at startup) can be modified to change permissions. -Alexey -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of RICHARD SPITZ Alexey, > To summarize the discussion, I'd suggest the following: > For production system, use RAW devices with Informix, but > reference them through symbolic links. I did just that (SLES 10 SP1), but to my great surprise had to discover that these symbolic links didn't survive a reboot. This is a significant change from our previously used SuSE 7.2, where this wasn't a problem. It seems that since the raw devices do not survive a reboot and have to be newly created by the script /etc/init.d/raw, symbolic links to these devices that reside under /dev are also deleted. I haven't tried yet if it makes a difference when these links do not reside under /dev. Are there any general recommendations about where these symbolic links should be put? I can probably write my own startup script that creates these symbolic links and takes care of the proper permissions etc., but I'd appreciate if anybody could post an already tested solution. Regards, Richard ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum. See you at the IIUG Informix 2008 Conference The Power Conference for Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas City), Kansas http://www.iiug.org/conf Registration Now Open!!