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Collecting IBM i performance data for sizing with Disk Magic Jana Jamsek ATS Europe. Typical IBM i workloads. Day timeframe On-line transactions Transaction response time is important Night timeframe Batch job Transactions Copying of libraries Save to tape
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Collecting IBM i performance data for sizing with Disk MagicJana JamsekATS Europe
Typical IBM i workloads • Day timeframe • On-line transactions • Transaction response time is important • Night timeframe • Batch job • Transactions • Copying of libraries • Save to tape • Duration of batch job is important • Depending on the customer’s preference size for Daily workload, Batch job, or both
Collection periods • Depending on the customer’s preference • Daily time • Batch job time • 24 hours • Recommended to collect during 3 consecutive days • plus Recommenced to collect during hevay End-of-month job
Needed data for sizing and modelling • Performance Tools (Collection Services) data – 5770-PT1 • Needed reports for sizing external storage • System report / Disk utilization • Resource report / Disk utilization • Component report / Disk activity • Note: System report / Storage Pool utilization is no more needed for Disk Magic
Determine the peaks • First, insert reports to Disk Magic just to obtain the data in Excell form to observe peaks
Determine the peaks - continue • Graphs from Disk Magic spreadsheet • Reports from 7 consecutive days 1. Oct candidate for peak
Determine the peaks - continue Peak in IO/Sec Peak for disk utilization • Graphs from Disk Magic spreadsheet • Read write ratio is important to determine the peak, because of RAID penalty on write operations
Determine the peaks - continue Peaks in blksize at low IO rate Big blocksizes during entire period: Usually no need for special sizing for blocksize Consider more resourcse
Best practise • Size for the peak for disk utilization • Consider big blocksizes if needed • Use Disk Magic to model • Peak by IO/sec • Peak by MB/sec • Peak by write MB/sec • Average
Considerations for multiple LPARs • Inserting reports from all LPARs to Disk Magic provides info about IO rate of the sum and of paritcular LPARs • For info reads , writes , and blocksizes insert reports of each LPAR separately to DM and save spreadsheet
Best practise • With multiple LPARs • If LPARs will use dedicated ranks size for the peak in each LPAR • If LPARs will share ranks size for peak of the sum; or size for the peak in each LPAR if they are important • Model the peaks of the sum