American Megatrends ManageTrends 2.7, User Manual

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StorTrends® 1300 User’s Guide (StorTrends iTX version 2.7) 202
How StorTrends Tiered Storage and CSM Works
The main challenges faced in re-striping data between LDs are as follows:
Challenge Solution
How often should the
data be re-striped? Whenever an existing container is expanded with an LD of the same cost.
Or every hour, when an analysis of the data presented in each container present in the
system is complete.
When should the data
be re-striped? When the I/O load on the system is low. The reason for this is to not affect the bandwidth
of the applications running above it. The method of predicting the I/O load on the system
at given point in time is done by the workflow analysis.
How should the data
be re-striped? The data should be re-striped in the manner that it is distributed equally across both the
LDs and with the minimum number of movements.
In what order should
the data be re-striped? It is beneficial to re-stripe the most frequently accessed data first in the system. This is
because this data, when it is re-striped, will be given a performance boost due to the extra
spindles, thereby having a net positive impact on the system performance.
Below is a pictorial representation of how the territories across the logical drives will be
striped when a container is expanded with a logical drive of the same cost.