During the creation of a FlashCopy logical drive
If numerous I/O requests are written to the base logical drive, the repository logical drive, which contains the FlashCopy data (information about the FlashCopy) and copy-on-write
The following procedure describes how to estimate the life expectancy of a repository logical drive. It should be noted that this should be used merely as a guide, and that a repository logical drives life expectancy should be carefully re-estimated periodically.
1 |
Highlight the repository logical drive in the Logical View. Select Logical Drive >> Properties and choose the Capacity tab or right-click on the repository logical drive and select Properties, then the Capacity tab. |
2 |
Highlight the repository logical drive in the Logical View. Select View >> Go To >> FlashCopy Logical Drive or right-click on the repository logical drive and select Go To FlashCopy Logical Drive. |
3 |
Record the creation timestamp day and time. |
4 |
Record the capacity used (GB) and the available capacity (GB). |
5 |
Determine the elapsed time (t) by subtracting the creation time from the current time, expressing the elapsed time in either minutes, hours, or days. The total time (Tr) the repository is available for copy-on-write data can now be estimated (based on the current usage) by multiplying the elapsed time (t) by the available capacity (Ct), then dividing the resultant number by the capacity used (Cu). Where: Tr = Total Time Available t = Elapsed Time Ct = Available Capacity Cu = Used Capacity Therefore: Tr = (t * Ct) / Cu Note: The Total Time Available (Tr) indicates the total usage time for the repository logical drive. |
Based on the results, you should now be able to make an informed decision on whether you should increase the capacity of the repository logical drive. If the repository capacity will become 100% full during the FlashCopy's expected lifetime, then you should increase the repository logical drive's capacity. For more information, see Increasing the Capacity of a Repository Logical Drive.