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© 2009 IBM Corporation Active Memory Sharing Overview Carol Hernandez, Power Firmware Architect.

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Presentation on theme: "© 2009 IBM Corporation Active Memory Sharing Overview Carol Hernandez, Power Firmware Architect."— Presentation transcript:

1 © 2009 IBM Corporation Active Memory Sharing Overview Carol Hernandez, Power Firmware Architect

2 © 2009 IBM Corporation IBM Power Systems 2 Outline Technology Overview –What is Active Memory Sharing –Value Proposition –Requirements –Configuration –Major Sub-Systems Deployment Considerations –Usage and Cost Savings –Performance –Methodology for Deployment Memory Utilization Improvement Use Cases –Time Zone Variant Workloads –High Availability Scenario –Physical Over-commitment

3 © 2009 IBM Corporation IBM Power Systems 3 What is Active Memory Sharing Active Memory Sharing intelligently flows memory from one partition to another for increased utilization and flexibility of memory usage Memory virtualization enhancement for Power Systems –Latest innovation in PowerVM virtualization: extends resource optimization to include memory –Can improve overall memory utilization similar to the way micro-partitioning improves CPU utilization –A pool of physical memory is dynamically allocated amongst logical partitions as needed to optimize overall memory usage in the pool Blends Power Systems hardware, firmware and software enhancements to optimize resources –Supports over-commitment of logical memory with overflow going to VIOS managed paging devices –Two paging VIOS partitions can be used for redundancy –Compatible with Live Partition Mobility More efficient utilization of memory through collaboration with Operating System –Enables fine-grained sharing of physical memory and automated expansion and contraction of a partitions physical memory footprint –Supports OS collaborative memory management to reduce hypervisor paging

4 © 2009 IBM Corporation IBM Power Systems 4 Active Memory Sharing Value Proposition Dynamically adjusts memory available on a physical system for multiple virtual images based on their workload activity levels: –Different workload peaks due to time zones –Mixed workloads with different time of day peaks (e.g. CRM by day, batch at night) –Ideal for highly-consolidated workloads with low or sporadic memory requirements Increases memory utilization in an autonomic manner –Memory is automatically re-allocated between participating partitions No user intervention required after set-up –Save minutes - hours compared to manual DLPAR memory between partitions Memory Usage (GB) Time Memory Usage (GB) Time Dynamically optimize memory across virtual images to improve memory utilization Time Memory Usage (GB) Workloads

5 © 2009 IBM Corporation IBM Power Systems 5 Active Memory Sharing Requirements Available with PowerVM Enterprise Edition –No additional cost System requirements: –IBM Power Systems server or blade with POWER6 processors –Virtual I/O Server (VIOS) –Firmware level: eFW –HMC v7.342 Operating systems supported: –AIX 6.1 TL3 –IBM i 6.1 plus PTFs –SUSE Linux Enterprise Server 11 Partition Configuration Requirements –Must use shared processors only - dedicated processor is not supported –All I/O must be virtualized through VIOS – dedicated I/O, including HEA and HCA, is not supported –4K pages only – 64K or larger pages are not supported* * Linux kernel emulates 64K pages

6 © 2009 IBM Corporation IBM Power Systems 6 Active Memory Sharing Configuration Shared Memory Pool –Specify desired and maximum pool size –Assign paging devices and paging VIOS Single or Redundant Paging VIOSes Shared Memory Partition –Partition Attributes Min, Max, Assigned Memory refer to logical memory. I/O Entitled Memory: maximum amount of physical memory available for I/O mapping. Memory Weight: partitions priority to get physical pages Paging VIOSes: single or redundant; primary and secondary paging VIOS (optional) –DLPAR memory operations change logical memory –Partition Mobility support: among AMS capable systems

7 © 2009 IBM Corporation IBM Power Systems 7 Active Memory Sharing Major Sub-Systems SM Partition 1 AIX Paging VIOS (1 GB) Page In / Out VASIVASI Virtualization Control Point (VCP) Shared Memory Pool: 16 GB Paging VIOS Paging Devices SM P1: Desired Mem= 12GB Entitled Mem: 4 GB SM P2: Desired Mem= 8GB Entitled Mem: 3 GB SM P3: Desired Mem= 4GB Entitled Mem: 1 GB Shared Memory Pool (16 GB) Free Memory (5.5 GB) Hypervisor Memory (1.5 GB) Dedicated Memory (9 GB) Physical Memory (32 GB) FCFC SM Partition 2 Linux SM Partition 3 IBM i Dedicated Memory Partition 4 (8 GB) AIX Paging Devices vSCSI Server CMM Shared Memory Manager (SMM) Page Loaning Virtualization Control Point User Interface –Create Shared Memory Pool –Create Shared Memory Partitions –Change Shared Memory Pool Configuration and partition attributes. –Switch between dedicated and shared memory partitions. –Profile I/O Entitled Memory Usage Firmware and OS Interfaces –Paging VIOS Interface to manage paging devices and allocate them to Shared Memory partitions. –Hypervisor interface to create and manage Shared Memory Partitions. –Client interface for DLPAR operations and dynamic partition attributes changes.

8 © 2009 IBM Corporation IBM Power Systems 8 Active Memory Sharing Major Sub-Systems (cont.) SM Partition 1 AIX Paging VIOS (1 GB) Page In / Out VASIVASI Virtualization Control Point (VCP) Shared Memory Pool: 16 GB Paging VIOS Paging Devices SM P1: Desired Mem= 12GB Entitled Mem: 4 GB SM P2: Desired Mem= 8GB Entitled Mem: 3 GB SM P3: Desired Mem= 4GB Entitled Mem: 1 GB Shared Memory Pool (16 GB) Free Memory (5.5 GB) Hypervisor Memory (1.5 GB) Dedicated Memory (9 GB) Physical Memory (32 GB) FCFC SM Partition 2 Linux SM Partition 3 IBM i Dedicated Memory Partition 4 (8 GB) AIX Paging Devices vSCSI Server CMM Shared Memory Manager (SMM) Page Loaning Shared Memory Manager (SMM) –Guarantee physical memory is available for I/O ops. –Manage and allocate physical memory in the pool among shared memory partitions, using: Page stealing based on OS page usage hints, memory weight, page usage statistics. Page loaning mechanism Hypervisor Paging (when all else fails). Paging VIOS Partition –Help SMM move partition page frames in and out of the Shared Memory Pool to a paging device Page In/Out requests received through VASI stream Operating System –Manage partitions I/O entitlement across device drivers and provides page usage hints to hypervisor. –Dynamically change partitions memory footprint in response to hypervisor page loaning requests (CMM: Collaborative Memory Manager).

9 © 2009 IBM Corporation IBM Power Systems 9 Outline Technology Overview –What is Active Memory Sharing –Active Memory Sharing Value Proposition –Active Memory Sharing Requirements –Active Memory Sharing Major Sub-Systems –Active Memory Sharing Configuration Deployment Considerations –Usage and Cost Savings –Performance –OS and VIOS –Methodology for Deployment Memory Utilization Improvement Use Cases –Time Zone Variant Workloads –High Availability Scenario –Physical Over-commitment

10 © 2009 IBM Corporation IBM Power Systems 10 Deployment Considerations: Usage and Cost Savings Usage –AMS provides the most benefit when the aggregate memory working sets for all partitions running concurrently can be backed by the physical memory in the pool. Variable workloads that peak at different times across the partitions Workloads with low average memory residency requirements Active/Inactive Partition Scenarios –AMS provides limited benefit and is not recommended for the following types of applications: Workloads with high, sustained memory residency requirements Response time and performance sensitive workloads Workloads with high degree of load variation –To understand the benefits of AMS, customers should run test trials on the new AMS functions prior to deploying in a production environment White paper and LBS are available to assist customer with their set-up / optimization Cost Savings –Reduction in real memory requirements may reduce cost of system configuration depending on specific workloads and performance requirements AMS allows creation of more partitions than would be otherwise possible Only actively referenced memory needs to stay resident in a workload memory footprint –AMS can save time and money of system admin who otherwise would be manually reallocating memory

11 © 2009 IBM Corporation IBM Power Systems 11 Deployment Considerations: Performance Partition 1 (becoming active) Partition 3 (inactive / app idle) (-1.6GB) (+1.6 GB) Application running full speed. Partition 4 (active) application running full speed Partition 2 (active) application running full speed Elapsed time (Minutes) Partition 2 and 4 workload performance protected Partition 3 workload idle but, memory not released by application Partition 1 started, memory removed from partition 3 until performance full speed –Performance depends on characteristics and usage model of the workloads that share the memory pool, memory configuration, and over subscription levels –Switching latency may vary depending on utilization across the shared memory partitions, configured memory, and paging devices When a large amount of memory is moved, there will be a ramp-up latency at the destination partition –When memory demand increases, the shared memory pool can be increased dynamically to avoid paging and improve performance Latency has to be monitored to initiate DLPAR memory add to the shared pool –High performance paging devices are required to minimize performance impact Solid State Devices and FASTt are recommended Example: Memory Bandwidth Workload

12 © 2009 IBM Corporation IBM Power Systems 12 Baseline – Dedicated Memory Partition –Determine the memory capacity needed for the workloads per partition Base Overhead - AMS with the same physical memory as dedicated memory scenario –Shared Memory Pool will have physical memory to cover the memory capacity determined in baseline measurements Logical Overcommit – Workloads peak at different times –Shared Memory Pool will have enough physical memory to cover the peaks at different time periods –Frequent change of loads might impact latency, additional memory may have to be added to the Shared Memory Pool to meet response time criteria Physical Overcommit – Workloads peak concurrently –Shared Memory Pool cannot back up all the memory in use at a time –If performance is not within acceptable level, go back to Logical Overcommit Methodology For Deployment

13 © 2009 IBM Corporation IBM Power Systems 13 Outline Technology Overview –What is Active Memory Sharing –Active Memory Sharing Value Proposition –Active Memory Sharing Requirements –Active Memory Sharing Major Sub-Systems –Active Memory Sharing Configuration Deployment Considerations –Usage and Cost Savings –Performance –OS and VIOS –Methodology for Deployment Memory Utilization Improvement Use Cases –Time Zone Variant Workloads –High Availability Scenario –Physical Over-commitment

14 © 2009 IBM Corporation IBM Power Systems 14 Active Memory Sharing: Time Zone Variant Workloads (No DLPAR) Time Zone Variant Workloads Logical Overcommit (2.4x)Required Physical Memory Dedicated Memory3x16GB = 48 GB Shared Memory1x16GB + 2x2GB = 20 GB System Memory (Dedicated Memory mode)12 x 4GB DIMMs = 48 GB System Memory (Shared Memory mode)5 x 4GB DIMMs = 20 GB Memory Utilization Improvement(48-20) GB / 48 GB = 58.3%

15 © 2009 IBM Corporation IBM Power Systems 15 Active Memory Sharing: High Availability Scenario HA - Logical Overcommit (2.5x)Required Physical Memory Dedicated Memory3x100GB = 300 GB Shared Memory10x10GB+20x1GB = 120 GB System Memory (Dedicated Memory Mode)10 x 32GB DIMMs = 320 GB System Memory (Shared Memory Mode)4 x 32GB DIMMs = 128 GB Memory Utilization Improvement( ) GB / 320 GB = 60% 100 GB 10 LPARs 120 GB 30 LPARs 100 GB 10 LPARs 100 GB 10 LPARs 300 GB 30 LPARs P1 P3 P2 P1 BU1

16 © 2009 IBM Corporation IBM Power Systems 16 Active Memory Sharing: Physical Overcommitment Physical Overcommit(1.25x)Required Physical Memory Dedicated Memory16GB+12GB+10GB = 40 GB Shared Memory40GB/1.25 = 32 GB System Memory (Dedicated Memory Mode)10 x 4GB DIMMs = 40 GB System Memory (Shared Memory Mode)8 x 4GB DIMMs = 32 GB Memory Utilization Improvement(40-32) GB / 40 GB = 20%

17 © 2009 IBM Corporation IBM Power Systems 17 Questions? Thank you Questions? –Carol Hernandez


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