DB2 - Problembeschreibung
Problem IC77857 | Status: Geschlossen |
STMM OVERCOMMITS MEMORY ON LINUX | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problembeschreibung: | |
STMM does not make sufficient allowance for system memory requirements in two cases: - memory which is paged out and only exists in paging space is not accounted for, which can result in continually increasing tunings if Linux is swapping out memory before DB2 perceives a system to be overcommitted - large file cache requirements due to a high amount of dirty pages. Dirty file pages cannot be reclaimed until they are laundered (written out), and contribute to the level of committed memory on a system. A high volume of dirty pages may be triggered by activity on tablespaces with buffered I/O (such as sort, reorgs in SMS temporary tablespaces where buffered I/O is the default), backups to disk, other. The lack of accounting for these two cases may contribute to swapping on the system. Note that vm.swappiness should be set to 0 on all DB2 system, otherwise swapping may occur on systems which are not overcommitted (memory requirements are not exceeding RAM). | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * DB2/Linux systems with self-tuning of Database Memory * * enabled (SELF_TUNING_MEM=ON, DATABASE_MEMORY=AUTOMATIC) * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 Version 9.7 Fix Pack 5 * **************************************************************** | |
Local-Fix: | |
Use DB2_BACKUP_USE_DIO for backups to disk, non-buffered DMS temporary tablespaces instead of SMS. Ensure vm.swappiness is set to 0. | |
verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows | |
Lösung | |
Problem first fixed in DB2 Version 9.7 Fix Pack 5 | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 31.07.2011 29.03.2012 29.03.2012 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FP5 | |
Problem behoben lt. FixList in der Version | |
9.7.0.5 |