Yeah, my server is configured with GB data files with 50MB dual log files w/ autolog activated so if this presents a problem with I/O on a ReiserFS system then I may need to build up a new server using ext2 and transfer the db to it.
What say Ye at SAP? Which is the best file system for SAPDB? journaled or not? -----Original Message----- From: "H�bschen, Peter" [mailto:[EMAIL PROTECTED] Sent: Friday, September 12, 2003 12:35 AM To: Kevin Wilson; 'Nigel Campbell (DSL AK)'; 'Arne Gehlhaar' Cc: Sapdb General List (E-mail) Subject: AW: Hard disk lit-up like Christmas tree ??? Hello, in my opinion this article seems to be a little bit unclear: Quote 1: "ReiserFS is more suited for work as a database server." Quote 2: "Though it provides fast performance when reading and writing small files, ReiserFS is fairly slow to manipulate large multi-megabyte files." I don't know other database systems nor other Database administrators, but I configured my SAPDB to use large files for storing my database, so ReiserFS would be the wrong choice (see Quote 2). Maybe there is a database system which stores its data in small files, then ReiserFS could be the right choice. Peter > -----Urspr�ngliche Nachricht----- > Von: Kevin Wilson [SMTP:[EMAIL PROTECTED] > Gesendet am: Donnerstag, 11. September 2003 16:27 > An: 'Nigel Campbell (DSL AK)'; 'Arne Gehlhaar' > Cc: Sapdb General List (E-mail) > Betreff: RE: Hard disk lit-up like Christmas tree ??? > > This article states that ReiserFS is particularly good for use on a > database > server machine, so which is correct? Is there just an issue with SAPDB > that > causes it to not work well with journaled file systems? I have ran MySQL > on > the ReiserFS for quite a while without any disk I/O issues at all. > > http://www.extremetech.com/article2/0,3973,1160504,00.asp > > Kevin > > -----Original Message----- > From: Nigel Campbell (DSL AK) [mailto:[EMAIL PROTECTED] > Sent: Wednesday, September 10, 2003 8:26 PM > To: '[EMAIL PROTECTED]'; Kevin Wilson > Subject: FW: Hard disk lit-up like Christmas tree ??? > > > You're better off with ext2 (or raw partitions if you're feeling > really keen) for a database. As a generalisation, it isn't > a good idea to put databases on a journalling file system for > the following reasons: > > (i) The journalling function is redundant as the database > does this anyway. This generates redundant disk > traffic. > > (ii) Journalled file system logs are most definitely not > optimised for database access patterns. Databases > generate lots of small writes to big files, which > create disproportionately large log entries with lots > of wasted space (i.e. entire 8k data-base blocks being > written by the db and journalled by the filesystem for > a single-row change). This wastes a large amount of > log space and places a big garbage colleciton burden > on the logs. In some journalling filesystsms such as > LFS the log entries become the new disk blocks for the > filesystem and the old ones are garbage collected - > which would aggravate the external fragmentation of > the database files. > > (iii) JFS's don't keep filesystem metadata up-to-date in > realtime - typically there is an asynchronous writer > process that goes through the log and writes out the > changes. On a busy system, this may lead to a lot > of journaled-but-not-written changes which are > inefficient, particularly if there is is significant > locality-of-reference. The logs can also run out of > space if a busy system can't keep up with the garbage > collection. > > I've seen an instance of Baan (an also-ran in the ERP racket) > being deployed on an HP-UX box with journalling filesystems. > This had persistent performance and space problems until > someone worked out that they were running the database on a > journalled filesystem. After they reformatted the partitions > as UFS (berkely FFS) the problems went away. > > Nigel. > > > > > -----Original Message----- > From: Kevin Wilson [mailto:[EMAIL PROTECTED] > Sent: Thursday, 11 September 2003 10:11 a.m. > To: Sapdb General List (E-mail) > Subject: Hard disk lit-up like Christmas tree ??? > > > [System] > SuSE v8.1 w/ using ReiserFS > SAPDB v7.3.0.34 > > Several sapdb processes are in a Uninterruptible Sleep state and > kreiserfsd > keeps popping in every so often. The hard disk is activity is very high > and > the database access is slower but still accessible. > > Any ideas? > > Kevin > > "Those who would give up essential liberty to purchase a little temporary > safety deserve neither liberty nor safety." > -Benjamin Franklin, 1759 > _______________________________________________ > 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 > _______________________________________________ > 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
