Guidelines for log size - assure_mimix - 6.0

Assure MIMIX for AIX Guide

Product type
Software
Portfolio
Integrate
Product family
Assure
Product
Assure MIMIX™ Software for AIX
Version
6.0
ft:locale
en-US
Product name
Assure MIMIX for AIX
ft:title
Assure MIMIX for AIX Guide
Copyright
2025
First publish date
2003
ft:lastEdition
2025-03-12
ft:lastPublication
2025-03-12T05:07:12.494000

All logs are the same size on the production server and the recovery server. The log size affects the amount of data that Assure MIMIX for AIX processes for each transaction.

Increasing log size has the following benefits:
  • Assure MIMIX for AIX processing is reduced.

  • Elimination of common blocks in the undo logs is more efficient.

Decreasing log size results in a more up-to-date replica on the recovery server because log transfers occur more frequently.

When you determine the best log size, keep these conditions in mind:
  • The production journal should contain at least 8 logs.

  • Minimum log size is 2 MB.

Note: Use the following equation to ensure that the space you allocate for LFCs coincides with the physical partition size of the VG where the LFC LVs are allocated. This enables you to utilize all the space in a LV. This is not a requirement, you can elect to not utilize all the available space in a LV.y = (number of LFCs / number of LFC LVs) * LFC sizeWhere y should be evenly divisible by the physical partition size of the VG where the LFC LVs are allocated.
  • Maximum log size is one-half of the available RAM on the recovery server.

To calculate log size, you need the following information:

  • Estimate of average write throughput

  • Required processing rate. For example, if Assure MIMIX for AIX processes one log every 60 seconds, the recovery server will be one minute behind the production server.

Calculate log size as follows:

log size = (average write throughput)/(processing rate)

Calculate the number of logs as follows:

number of logs = (journal size)/(log size)