Oracle Performance On Linux X86 systems
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On X86 systems, using an Unbreakable Enterprise Kernel (UEK) is recommended over other enterprise distributions as it provides better hardware support, security patches, and testing from the larger Linux community. Key configuration recommendations include enabling maximum CPU performance in BIOS, using memory types validated by Oracle, ensuring proper NUMA and CPU frequency settings, and installing only Oracle-validated packages to avoid issues. Monitoring tools like top, iostat, sar and ksar help identify any CPU, memory, disk or I/O bottlenecks.
![• DB Smart Flash Cache is new (11.2) extension for buffer cache area.
• extension to the SGA as L2 cache
ID 1317950.1
db_flash_cache_file = <+FLASH/filename>
db_flash_cache_size = <flash pool size>
alter [table|index object_name] storage (flash_cache keep);](https://image.slidesharecdn.com/5c57cb43-8015-4caa-966a-3543e20b8d15-150630164559-lva1-app6892/85/Oracle-Performance-On-Linux-X86-systems-30-320.jpg)
Oracle Performance On Linux X86 systems
- 1. On X86 systems Baruch Osoveskiy Senior Consultant Brillix
- 2. Who Am I • Senior Consultant in brillix • Unix-Linux System Admin since 1997 • DBA oracle and MySQL since 2000 • Linux and security Consultant • blogger in ildba.co.il
- 3. • Enterprise Distributions • Kernel • Packages • Drivers
- 4. ◦ Use Unbreakable Enterprise Kernel (UEK), Redhat , Suse Whey ? Better optimized for large systems and workloads Better hardware support Modern Linux features Patches required for correct Oracle product operation
- 5. • Bug Fixes from upstream • Most Bug Fixes originate Upstream and are backported to Enterprise Distributions • More code change from upstream means more time before patches are backported -- if it’s even possible to do so • More time for security patches to be backported to the Enterprise versions • Bug Fixes in Upstream apply cleanly to UEK • Better testing • Code is tested by the whole Linux community, not dependent on one OS vendor and their customers • You run the same code that’s in upstream • No backporting/scaffolding to use the latest Linux kernel features (i.e. NFSv4, TCP fast open, etc) • Better contributions • Largest amount of Developers and Company Contributions • Major Backports not required to provide cutting edge features • New features seamlessly used by Oracle products
- 6. • Updates contain critical security and bug fixes. • Most Enterprise Distribution updates contain new features. • “Security Errata” can contain new features • Updates often contain 1000s of lines of new code from upstream. • Includes features, bug fixes, enhancements and other tweaks • Install Only security and bug fixes to avoid down time from new and untested features • The DB server is not your Laptop do not install unknown/new software.
- 7. • Use Oracle validated • http://www.oracle.com/technetwork/server-storage/linux/validated-configurations- 085828.html • Install only base + Oracle validated packages • Do not install games, applications .. on the production servers
- 8. #cd /etc/yum.repos.d # wget http://public-yum.oracle.com/public-yum-ol6.repo # yum list #yum install oracle-rdbms-server-11gR2-preinstall
- 9. • BIOS • CPU • Memory TYPE , swap • Disk (Disks in the more the better ) • Virtualization
- 10. Motherboard Handle 0x0003, DMI type 2, 16 bytes Base Board Information Manufacturer: Intel Product Name: S5000PAL0 Processor Processor Information Version: Intel(R) Xeon(R) CPU X5355 Memory Handle 0x0034, DMI type 17, 27 bytes Memory Device Data Width: 64 bits Size: 2048 MB Form Factor: DIMM Set: 1 Locator: ONBOARD DIMM_A1 Bank Locator: Not Specified Type: DDR2 Type Detail: Synchronous Speed: 667 MHz (1.5 ns) • Motherboard 4 Memory Channels (S5000PAL0) 8 Slots (A1/A2/B1/B2/D1/D2)Channels • CPU Intel ClovertownCPUs 1333Mhz (Dual Independent FSB) Bandwidth 10666 MB/s per FSB 21 GB/s Maximum FSB Bandwdith • Memory Memory DDR2 667 = PC2-5300 4 Memory Channels at 5.3GB/s each Memory Bandwidth of 21 GB/s from all 4 channels 16GB memory in total http://ark.intel.com/
- 11. • Always check for appropriate BIOS settings Look out for: • CPU features • Enable Maximum Performance in the BIOS • Memory • Enable numa • Power Management
- 12. • will give you 35% better performance ( Test On OLTP). • SMT Simultaneous Multi-Threading • Run 2 threads at the same time per core • Do I have HT ? • Ensuring that HT is enabled at the BIOS. • grep -e "model name" /proc/cpuinfo • http://ark.intel.com/ • Do not Enable TH on I/O bound server it only will make it worse.
- 13. cpufreq you can dynamically scale processor frequencies through the CPUfreq subsystem. ◦ Enable Maximum Performance in the BIOS ◦ /sys/devices/system/cpu/cpu<n>/cpufreq/scaling_governor ◦ On Redhat 5.x default is performance ◦ On Redhat 6.x default is normal ◦ echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
- 14. sudo modprobe cpufreq_conservative sudo modprobe cpufreq_ondemand sudo modprobe cpufreq_powersave sudo modprobe cpufreq_stats sudo modprobe cpufreq_userspace /etc/init.d/cpuspeed status echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor grep -i mhz /proc/cpuinfo cpu MHz : 2367.330
- 15. • Load of more then n on n cpu server is bad • Load of n cpu on n cpu server is good = load of 1.00 = load of 0.50 = load of 1.70
- 16. • Use Load to find if the server is CPU bound • one, five, and fifteen minute averages • In LINUX CPU bound can impact I/O
- 17. cat /proc/meminfo ◦ Free = Cached + Free ◦ All free space on Linux is used for pagecache. ◦ This behavior can be controlled by cgroups. ◦ PageTables large use HugePages. /dev/shm ◦ implementation of traditional shared memory (ramfs ) ◦ Used by Automatic Memory Management ( AMM MEMORY_TARGET ) ◦ Not working with Hugepages ID 1134002.1
- 18. • Oracle will recognize NUMA systems and adjust memory and scheduling operations accordingly and NUMA technology allows for faster communication between distributed memory in a multi-processor server. ID 759565.1 • !! Disabling or enabling NUMA Will change application performance. !! • 8 sockets and beyond may see gains of approximately 5% • Enbale on bios level and in grub.conf remove numa=off • _enable_NUMA_optimization=TRUE (look for bugs on your version before enable) • dmesg | grep -i numa NUMA: Initialized distance table, cnt=2 NUMA: Node 0 [0,c0000000) + [100000000,1040000000) -> [0,1040000000) pci_bus 0000:00: on NUMA node 0 (pxm 0) pci_bus 0000:80: on NUMA node 1 (pxm 1)
- 19. • Without HugePages the memory of the is divided into 4K pages • Using HugePages the page size is increased to 2MB (configurable to 1G ) • HugePages reducing the total number of pages to be managed by the kernel • reducing the amount of memory required to hold the page table in memory.
- 20. • Use Hugepages Oracle Doc ID 749851.1 • Reduce footprint of individual Oracle database connections. • Increase performance and scalability with fewer tlb misses. • Requires manual tuning after SGA changes, and does not work with AMM (/dev/shm).
- 21. Without Hugepages o 200 Connections to a 12.9GB SGA o Before DB Startup Pagetables: 7400 kB o After DB Startup Pagetables: 652900 kB o After 200 PQ Slave run query o Pagetables: 6189248k o Time to complete: 00:10:23.60 With Hugepages o 200 Connections to a 12.9GB SGA o Before DB Startup PageTables: 7748 kB o After DB Startup Pagetables: 21288 kB o After 200 PQ slaves run query o Pagetables: 80564 kB o Time to complete: 00:00:18.77
- 22. Use Hugepages with VMs for non-swappable, shared pagetables. Hugepages must allocated in the guest VM and the hypervisor Oracle VM 3.2.6 contains support for pv-hugepages
- 23. What about Swap? ◦ Modern Linux distributions Do not use Swap (swappiness is very low ) ◦ Swap is for OS services only. I do not recommend swap = ram. ◦ Check vmstat output: ensure swap ◦ Do not use Swap as memory – buy more memory ◦ If you have free memory echo 10 > /proc/sys/vm/swappiness vm.swappiness in /etc/sysctl.conf
- 24. • Disks – the more the better • Do not mix. • Use RAID • Use Hardware RAID • RAID 1+0 is best for write performance (logs). • RAID 5 is best for read performance. RAID Level Total array capacity Fault tolerance Read speed (4k) Write speed (4k) RAID-1+0 500GB x 4 disks 1000 GB 1 disk 2X 2X RAID-5 500GB x 3 disks 1000 GB 1 disk 3X Speed of a RAID 5 depends on controller
- 25. • High “log file sync” event time . • Do Not Use Raid 5 on Redo Logs (low write performance). • Upgrading the CPU enabled more throughput increase for redo (LGWR also requires CPU) • reducing the overall number of commits by batching transactions can have a very beneficial effect. • See if any of the processing can use the COMMIT NOWAIT option. • See if any activity can safely be done with NOLOGGING / UNRECOVERABLE options. • Enlarge the redologs so the logs switch between 15 to 20 minutes. • ID 34592.1
- 26. On Linux Use ASM (Block/RAW Device, O_DIRECT ) Raw Devices deprecated by OUI for Oracle 11.2 ID 357492.1 Raw Devices may still bring benefits for intensive redo and large redo log files Use udev or asmlib to Control Devices
- 27. If using file system Bypass journaling when you create a file system., use EXT-2 or EXT-4 with journaling turned off, journaling turned off eliminates double writes. “noatime” option eliminates the need for the system to create writes to the file system when objects are only being read. To Creaet partition and to disable DOS compatibility fdisk -c -u /dev/sda1 To turn off journaling, execute: tune4fs -O ^has_journal /dev/sda1 mount -t ext4 -o noatime /dev/sda1 /oradata
- 28. Device w/s wMB/s avgrq-sz avqqu-sz avwait svctm %util sdb1 21357.33 167.86 16.10 1.51 0.07 0.02 44.53 Device w/s wMB/s avgrq-sz avqqu-sz avwait svctm %util sdd1 3343.00 130.68 80.06 3.25 0.97 0.25 83.97 SSD HDD iostat information recorded during the ASM tests SSD/RAW, HDD/RAW, 50GB over a 5 minute period the redo on the 8 x SSD drives is writing 1.28X more data per second and doing 6.4X the writes/second although the avgrq-sz shows that the HDD configuration is writing more data for each operation. However, the avwait, svctm and %util show the the HDD configuration is busier and responding slower.
- 29. • Top 5 Timed Events (AWR) looked as follows: Event Waits Time(s) Avg wait (ms) % DB time Wait Class DB CPU 19,832 78.42 log file sync 6,700,242 4,059 1 16.05 Commit Event Waits Time(s) Avg wait (ms) % DB time Wait Class DB CPU 14,255 52.53 log file sync 5,366,376 12,709 2 46.83 Commit SSD HDD
- 30. • DB Smart Flash Cache is new (11.2) extension for buffer cache area. • extension to the SGA as L2 cache ID 1317950.1 db_flash_cache_file = <+FLASH/filename> db_flash_cache_size = <flash pool size> alter [table|index object_name] storage (flash_cache keep);
- 32. • Look for high I/O wait (%wa in top, await iostat) • Look at %util for disk saturation. • In the AWR most of DB Time is I/O.
- 33. Virtualization performance is proportional to native performance VM Drivers Vs Native Drivers Have ~16% Overhead
- 34. • top • iostat –Nx 1 100 • Sar • Ksar • Oracle Orion Calibration Tool http://docs.oracle.com/cd/E11882_01/server.112/e16638/iodesign.htm#PFG RF95244
- 35. • From Redhat 6.x (6.2 best) and EUK 3 • cgroups: Control Groups for Linux Containers • Provide fine grained control over system resources • Can be used to throttle page cache use by backup processes - Often the reason why systems are slower after overnight backups
- 36. cgroup
- 37. Cgroup How To Use yum install libcgroup /etc/init.d/cgconfig start /etc/cgconfig.conf mount { cpu = /cgroup/cpu; memory = /cgroup/memory; } group http { memory { memory.limit_in_bytes = 10M; }
Editor's Notes
- #4: אני אדבר על 2 חלקים נפרדים התוכנה וההפצות וחומרה הם כמובן נפגשים אבל יש להם במצגת שלי שתי חלקים נפרדים
- #5: הרבה משתשמים ב centos או בפדורה החבילות שם לא ניבדקו הם מעולם לא עברו QA ויכול להיות מצב שמי שקימפל את החבילות עשה עבודה גרוע ואתם תגלו את זה בראשון לחודש בשלוש בלילה ביום שישי .
- #7: The DB server is not your Laptop do not install unknown/new software.
- #8: השתמשו באתר oracle validate Install only base + Oracle validated packages
- #18: כמה זיכרון יש לשרת ? מה זה /dev/shm
- #28: התשמשו ב block אפשר גם ב row יש יתרונות ל row כאשר יש כתיבות גדולות Raw נתמח אבל דפריקדט
- #30: נוכל להעמיס יותר את ה SSD הבעיה העיקרית של SSD היא הכתיבה מחדש . מחיקה לוקחת זמן רב
- #32: יש יכולת מעניינת ל 11.2 הרחבה של ה SGA
- #41: היום אנחנו ב UEK 3