A healthcare organization is migrating its digital imaging archive and operational databas… — Google Cloud Professional Cloud Architect

A healthcare organization is migrating its digital imaging archive and operational database from an on-premises data center to Google Cloud within a strict 14-day migration window. The data consists of $180\text{ TB}$ of static DICOM medical imaging files and a $1.2\text{ TB}$ transactional PostgreSQL database. The data center has a dedicated $200\text{ Mbps}$ internet connection available for data transfer. The application requires that database downtime during the final cutover must not exceed 1 hour. Which migration strategy should you recommend?

Order a Google Cloud Transfer Appliance to transfer the 180 TB imaging archive offline to Cloud Storage, and use Database Migration Service (DMS) with continuous replication for the PostgreSQL database.Cevap
B
Use Storage Transfer Service to stream both the 180 TB imaging archive and the PostgreSQL database backup directly over the 200 Mbps internet connection.
C
Migrate the PostgreSQL database by converting it to Cloud Spanner using Storage Transfer Service, while transferring the imaging archive over HA VPN tunnels.
D
Provision an HA VPN connection over the 200 Mbps link to compress and transfer both the imaging files and the PostgreSQL database before restoring them in Google Cloud.

Cevap

Order a Google Cloud Transfer Appliance for the 180 TB imaging archive and use Database Migration Service (DMS) with continuous replication for the PostgreSQL database.

The correct strategy combines offline physical transfer (Transfer Appliance) for large static archives with continuous online replication (Database Migration Service) for transactional databases. Transferring 180 TB over a 200 Mbps network line would take over 80 days, making offline appliance transport necessary to meet the 14-day window. Meanwhile, Database Migration Service continuously synchronizes PostgreSQL changes over the network, enabling a fast cutover that satisfies the sub-1-hour downtime requirement.

Adım Adım Çözüm

Calculate network transfer time for the unstructured imaging data

Transferring

180\text{ TB}

(

1.44 \times 10^{15}\text{ bits}

) over a

200\text{ Mbps}

(

2 \times 10^8\text{ bps}

) network line requires

\frac{1.44 \times 10^{15}}{2 \times 10^8} = 7,200,000\text{ seconds} \approx 83.3\text{ days}

, exceeding the 14-day window.

Determines whether online streaming or offline appliance transfer is necessary.

Select the offline transfer mechanism for static archives

Use a Google Cloud Transfer Appliance to transport the

180\text{ TB}

static DICOM files offline.

Allows petabyte-scale data ingestion into Cloud Storage without saturating or exceeding the timeline of the network connection.

Select the online database migration mechanism

Use Database Migration Service (DMS) to migrate the

1.2\text{ TB}

PostgreSQL database to Cloud SQL for PostgreSQL with continuous CDC replication.

DMS performs an initial dump and continuously replicates change logs over the network, allowing a near-zero downtime cutover well within the 1-hour requirement.

Anahtar Kavram

Selecting data transfer mechanisms based on bandwidth math and downtime constraints

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