HP MSA1000 storage works raid array 201723-B21 전단

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201723-B21
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What Exactly is Tiered Storage?
Two years ago, storage tiering meant moving data contained in high performance, high availability, 
and higher cost disk array subsystems off to lower performance/lower cost per GB devices. Data sets 
that were candidates for this migration process were those whose activity levels had diminished over 
some predetermined period of time.  Data sets that supported critical applications and saw the most I/O 
activity received the highest priority and were therefore allocated to the “gold standard” arrays within 
the IT environment. Data sets with less activity or less importance in terms of application criticality were 
moved to lower performing/higher capacity arrays (SATA for example.)  By adding slower, capacity-
weighted disk arrays based on SATA and FATA to its normal complement of high performance, high 
availability arrays,  an intermediate disk storage tier (tier 2) that lived between “gold standard” arrays 
(tier 1) and nearline tape (tier 3) was created.
Today, additional tiering strategies have emerged that are based on other factors including availability 
and data protection levels as well as regulatory compliance and corporate governance requirements.  
Alternative tiering architectures are also emerging.  For example, storage tiering may now be enabled 
by storage virtualization; that is, multiple disk arrays composed of the same drives
1
 may be managed 
by a virtualized array controller.  It also enables disk array generations
2
  to be managed by a virtualized, 
heterogeneous storage controller.
Today, a good working definition for tiered storage is:
"The use of storage systems that have different performance, scale and cost 
characteristics. It is the assignment of different categories of data to different types of 
storage devices and media based on access, availability, and scalability needs as well 
as business policies including, in some cases, compliance needs. Policy-based data 
migration functions move the data across tiers in accordance with business policies 
while backup works throughout the storage environment to meet business continuity 
and disaster recovery requirements." 
Tiered storage means more than adding arrays of intermediate disk such as SATA arrays. Here we 
summarize the options now available to storage administrators.