IBM Storage Insights: Capacity changes for devices with FlashCore Modules
John Walsh (ID) 2700028UXA Visits (441)
In the fourth quarter 2019 release of IBM Storage Insights (and IBM Spectrum Control Version 5.3.5), we're changing how we report capacity for storage systems that use hardware compression.
Capacity usage is now reported based on the physical rather than the effective capacity of the storage system.
This change will make it easier to see when you are running out of space on the device.
What storage systems are impacted:
Two notions of capacity for these storage systems:
Example: A device with FlashCore Modules has a physical capacity of 10TiB but might have effective capacity of 25 TiB after compression.
After the IBM Storage Insights update:
Pro tip: Review the alert threshold values for block storage systems and pools. Since the capacity values are now based on physical capacity, you might want to reduce the threshold value at which the alerts fire for your affected devices.
In the following chart simulation, the "Before Update" values represent the effective capacity and the "After Update" values represent the physical capacity, which is lower.
This update affects capacity alerts for storage systems and pools in IBM® Storage Insights Pro. After the update completes, you'll see a sharp drop in the reported capacity values and that might cause the following alerts to trigger:
New alerts are available to monitor the effective capacity values. Check for alerts that begin with Effective.
Pro tip: For devices that use hardware compression, you can now define alerts to monitor physical capacity at the pool level. Previously, it was only possible to monitor physical capacity at the RAID array level.
Block Storage Systems and Pools
Two sets of capacity values are now shown for storage systems and pools.
1. The existing capacity columns (highlighted below) now show physical capacity values.
2. New columns were added to show the effective capacity based on the data reduction savings that are achieved with hardware compression. Just check the column names in the GUI that begin with Effective, such as Effective Capacity (GiB) and Effective Used Capacity (%).
For a full breakdown of the all the changes to the Pools and Block Storage Systems view
Changes to historical charting
In historical capacity charts for storage systems and pools, you'll see a sharp drop in the values for capacity, allocated space, and available pool space. That's because capacity values are now measured based on the physical capacity rather than the effective capacity.
Changes to capacity overview chart
The Physical Capacity chart for storage systems now shows physical capacity values rather than effective capacity. After the update, you'll see a sharp drop in the allocated, unallocated, and total space values that are shown on the chart.
For more information about these changes, see
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