To store medical imaging data across three sites with the requirement that each object exists at all sites at all times, which ILM rule meets this?

To store medical imaging data across three sites with the requirement that each object exists at all sites at all times, which ILM rule meets this?

• A. 2-copy replicated rule
• B. 3-copy replicated rule
• C. Erasure coding 4+2
• D. EC 2+1 across 3 sites

Answer: (B)

This item is about ensuring data is present as full copies at multiple sites, focusing on replication policy to meet strong availability requirements. To meet the need that each medical imaging object exists at all sites, you want three complete replicas, one at each site. A 3-copy replicated rule places a full copy of every object on every site, guaranteeing that all sites hold the complete data set and that data remains accessible even if one site goes down. This is the only option among the choices that guarantees a complete object at each site. Two-copy replication only creates two full copies, leaving one site without a local copy. Erasure coding with 4+2 distributes data as fragments plus parity and does not store three full replicas at three sites; while it can tolerate failures with less storage, it does not ensure a full object is resident at every site. EC 2+1 across three sites similarly splits data and parity across sites rather than providing complete replicas at each site. So, the best fit for the requirement is the three-copy replicated rule.

This item is about ensuring data is present as full copies at multiple sites, focusing on replication policy to meet strong availability requirements.

To meet the need that each medical imaging object exists at all sites, you want three complete replicas, one at each site. A 3-copy replicated rule places a full copy of every object on every site, guaranteeing that all sites hold the complete data set and that data remains accessible even if one site goes down. This is the only option among the choices that guarantees a complete object at each site.

Two-copy replication only creates two full copies, leaving one site without a local copy. Erasure coding with 4+2 distributes data as fragments plus parity and does not store three full replicas at three sites; while it can tolerate failures with less storage, it does not ensure a full object is resident at every site. EC 2+1 across three sites similarly splits data and parity across sites rather than providing complete replicas at each site.

So, the best fit for the requirement is the three-copy replicated rule.