HP StoreAll Storage - Manual (Page 181)

16 Using data tiering
A data tier is a logical grouping of file system segments. After creating tiers containing the segments
in the file system, you can use the data tiering migration process to move files from the segments
in one tier to the segments in another tier.
For example, you could create a primary data tier for SAS storage and another tier for SATA
storage. You could then migrate specific data from the SAS tier to the lower-cost SATA tier. Other
configurations might be based on the type of file being stored, such as storing all streaming files
in a tier or moving all files over a certain size to a specific tier.
X9000 data tiering is transparent to users and applications and is compatible with X9000 software
file system snapshots and other X9000 data services.
Migration is a storage and filesystem intensive process which, in some circumstances, can take
days to complete. Migration tasks must be run at a time when clients are not generating significant
load. Migration it is not suitable for environments where there are no quiet times to run migration
tasks.
IMPORTANT: Data tiering has a cool-down period of approximately 10 minutes. If a file was
last accessed during the cool-down period, the file will not be moved.
Configuring data tiers
Complete the following steps to configure data tiering:
•
Assign segments to tiers. You can create any number of tiers. A tier cannot be on tape or on
a location external to the X9000 file system, such as an NFS share.
•
Define the primary tier. All new files are written to this tier.
•
Create the tiering policy for the file system. The policy consists of rules that specify the data
to be migrated. The parameters and directives used in the migration rules include actions
based on file access patterns (such as access and modification times), file size, and file type.
Rules can be constrained to operate on files owned by specific users and groups and to specific
paths. Logical operators can be used to combine directives.
Assigning segments to tiers
Segments can be assigned to tiers when a file system is created or expanded, or at times when a
migration task is not running. Similarly, tier assignments can be changed or removed at any time,
provided that no migration tasks are running.
On the GUI, select Filesystems from the Navigator and select a file system in the Filesystems panel.
In the lower Navigator, select Segments. The Segments panel displays all of the segments in the
file system.
Configuring data tiers 181