To maximize efficiency, you should follow certain guidelines when using reallocation scans.
The following are good practices to follow when you choose to use the
reallocate command:
- You should define a reallocation scan when you first create the LUN, file, or volume. This ensures that the layout remains optimized as a result of regular reallocation scans.
- You should define
regular reallocation scans by using either intervals or schedules. This ensures that the layout of the LUN, file, or volume remains optimized. If you wait until most of the blocks in the layout of the LUN, file, or volume are not sequential, a reallocation scan will take more time.
- You should define
intervals according to the type of read/write activity associated with the LUN, file, or volume:
- Long intervals—You should define
long reallocation scan intervals for LUNs, files, or volumes in which the data changes slowly, for example, when data changes as a result of infrequent large write operations.
- Short intervals—You should define
short reallocation scan intervals for LUNs, files, or volumes that are characterized by workloads with many small random write and many sequential read operations. These types of LUNs, files, or volumes might become heavily fragmented over a shorter period of time.
- If you do not know the type of read/write activity associated with the LUNs, files, or volumes, you can choose to rely on the default layout of the system.
