I am a regular lurker on the list but have run sapdb in some testing before.
I recently installed a RAC 9i Cluster using raw devices on redhat advanced server. To configure raw devices on a redhat machine with an attached san the procedure is very easy. present a lun carve up the space into partitions with fdisk map the partition to raw device in /etc/sysconfig/rawdevices service rawdevices start Using raw devices works well but it does have some drawbacks. Just as Ralph explained your backup strategy will need to be looked at. A raw device cannot just be dumped to tape you need some way of dumping the data into a format that can be saved. It is also harder to maintain and you need to keep a good handle on what is mapped where in case you ever outgrow a presented partition. Cliff Baeseman Greenheck Fan Corporation Linux Systems Engineer -----Original Message----- From: Dr. Ralf Czekalla To: Derek Hamilton Cc: Peter Willadt; [EMAIL PROTECTED] Sent: 3/28/03 5:28 PM Subject: Re: Raw Devices Hi folks, the performance improvement depends on the used hardware. If you have a storage server (EMC, FuSi, IBM, NEC, have I forgotten one :-) with huge amount of cache, this improvement might be very small. But smaller installations with standard RAID5 for Data and RAID1 for Log and much smaller caches might show an greater improvement. But you have to test it to say this for sure. For setting up RAW devices please have a look into the SLES7 documentation. I assume that the SLES8 have the same info or better. At the end of that docu you will find a detailed manual how to set this up with SuSE. This might be the same for RedHat but never used it so far and won't. It's even possible to use Volume Manager inbetween but as far as I know it is not supported for R/3 on Linux. But this info is some month old and I don't know the current status. Nevertheless I set up a R/3 with Volume Manager and RAW devices in December 2001 and it worked reliable so far. Bye Ralf Derek Hamilton wrote: > > Thanks Peter, > > I was also wondering... > > 1) Is there a performance improvement? > > 2) Where can I find info on setting sapdb up with raw devices? > > Thanks, > Derek > > > You just get more safety. > > Nothing will interfere between sapdb and your platter, so you can be sure > that > > when sapdb commits the transaction is physically stored. > > Also not other software can mess around with your data, and you do not > have to > > think about fragmentation and things like that. > > > > As the manual says, raw devices are extremely safe. > > > > The main disadvantage is probably that you have to do a database backup to > > save your data, even when your database is not running most of the time. > > > > _______________________________________________ > sapdb.general mailing list > [EMAIL PROTECTED] > http://listserv.sap.com/mailman/listinfo/sapdb.general -- Ciao Ralf __________________________________________________________________ Dr. Ralf Czekalla Tel.: 06224/922810 Am Galgenbuckel 10 mailto:[EMAIL PROTECTED] D-69207 Sandhausen http://www.Czekalla.com __________________________________________________________________ Dr. Ralf Czekalla mailto:[EMAIL PROTECTED] _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
