As part of upgrading to SLES 11, priority-scheduling settings for workloads are migrated from the SLES 10 system. If you have in-depth understanding of PD set configuration, you may want to use the Pre-Migration Tool to refine the otherwise automatic results of this process.
Transitioning from SLES 10 PSF-licensed systems carries the following unique requirements related to workload migration.
- To use the Pre-Migration Tool, you must first convert PD sets to rule sets while still running Teradata Database 13.0 or earlier.The Pre-Migration Tool provides direct access to the Teradata utilities used to review PD set configurations and convert PD sets to rule sets. Additional related information can be found in the following Orange Books:
- Using Teradata’s Priority Scheduler, 541-0004940-A02
- Teradata Workload Analyzer, A Teradata Active System Management Component, Best practices and Recommendations, 541-0006735-A02
- Teradata Active System Management, Usage Considerations & Best Practices, 541-0004755-A01
- If you are migrating workloads based on user-defined SLES 10 performance groups, you must be running Teradata Database version 14.10 or later or 14.00.04.01 at the time of operating system upgrade to ensure that workloads based on default performance groups are assigned the expected timeshare access level in SLES 11.
Regardless of whether you use the tool, use the Workload Designer portlet in Teradata Viewpoint post upgrade to review and adjust workload-management settings as necessary.
Default Results of Workload Migration from PSF-Licensed Systems
-
All SLES 10 rule sets and workloads are migrated.
This result is subject to modification by using the tool only with the following Teradata Database versions: 13.10; 14.0 earlier than 14.0.4.1; and 14.10 earlier than 14.10.1.1. When you use the tool to select rule sets for migration from any of these database versions, only those rule sets and their corresponding workloads are migrated. For all other Teradata Database versions that support using the tool, all SLES 10 rule sets are migrated regardless of selection.
- All performance groups are converted to timeshare workloads.
- The workloads created based on the default performance groups are automatically assigned timeshare access levels based on account string as shown in the following table.
SLES 10 Account String SLES 11 Access Level $R* Top $H* High $M* Medium $L* Low The workloads created based on expedited user-defined performance groups are assigned the Top access level. The workloads created based on all other user-defined performance groups are assigned access level values based on SLES 10 allocation group relative weight as shown in the following table.
Access level affects the resource volume provided to timeshare workload queries, known as query access rate , at a ratio of 2:1. Queries in a Top workload receive eight times the resource volume as queries in a Low workload, four times the resource volume as queries in a Medium workload, and two times the resource volume as queries in a High workload. Use the Pre-Migration Tool to change the workload access level values as necessary.SLES 10 Allocation Group Relative Weight SLES 11 Access Level > 10% Top > 5% to 10% High > 2% to 5% Medium 0 to 2% Low For ease of identification, SLES 11 workloads created from SLES 10 user-defined performance groups are named and assigned an account string that reflects the performance group name. The SLES 11 workloads created from the SLES 10 default performance groups are named as shown in the following table.You cannot change workload names using the Pre-Migration Tool, but you can subsequently change them using the Workload Designer portlet in Teradata Viewpoint.SLES 10 Performance Group SLES 11 Timeshare Workload Name $R* T-WD $H* H-WD $M* M-WD $L* L-WD - Only settings in the System GDO are migrated.
- All workloads are placed in the single, default Standard virtual partition.
- The rule set that was active at the time of migration is automatically activated.
- Query milestones are lost. However, you can achieve similar results following upgrade to SLES 11 by using the Workload Designer portlet in Teradata Viewpoint to enable the Decay option for timeshare workloads.
- Two throttles to limit system concurrence are provided: GeneralQuery (with a limit of 52) and OneSecondQuery (with a limit of 30). You can use the Workload Designer portlet post upgrade to change or delete these throttles, as required.
- Allocation group and resource partition CPU limits are lost.
- Ability to swap night/day setup is lost.
Pre-Migration Workload Configuration Options for PSF-to-IWM Upgrades
- Reclassify automatically designated timeshare workloads as tactical workloads, if they are reserved for highly critical queries with response-time requirements of 1 second or less, and, therefore, should be expedited.
- Adjust access levels for timeshare workloads to meet priority-scheduling goals.
Pre-Migration Workload Configuration Options for PSF-to-TASM Upgrades
- Reassign automatically designated timeshare workloads to SLG tier 1.
If any automatically designated timeshare workloads meet the criteria for SLG tier assignment, use the tool to reclassify them accordingly. The SLG tier should be reserved for workloads that are of secondary importance to tactical workloads but are associated with a short service level goal or service level expectation; require a short response time due to business importance; and do not generally consume a significant amount of CPU resources.
-
Change allocation percentages for SLG workloads.
Without pre-migration intervention, each workload assigned to the SLG tier is by default allocated 5% of tier resources. Use the Pre-Migration Tool to change these values as necessary.
After upgrading to SLES 11 and monitoring the outcome of your original settings, you can adjust SLG workload allocation percentages using the Workload Designer portlet in Teradata Viewpoint.