An application is running on XtremlO replicating to another XtremlO using RecoverPoint with the following: Journal size= 1.05 * (write traffic) * (rollback time in seconds) / (1 - image access log percentage) + (reserved for marking) . Average write traffic = 5 Mb/s . Required rollback time = 24 hours What is the minimum required size for the Journal volume using the default parameters?

The calculation determines the required journal size based on write traffic, rollback time, and default overheads. The key is to convert all units to be consistent (e.g., Gigabytes) and correctly interpret "Mb/s" as Megabits per second.
1. Convert Write Traffic: 5 Mb/s ÷ 8 = 0.625 MB/s.
2. Convert Rollback Time: 24 hours × 3600 seconds/hour = 86,400 seconds.
3. Calculate Total Data: 0.625 MB/s × 86,400 s = 54,000 MB.
4. Convert to GB: 54,000 MB ÷ 1024 MB/GB = 52.73 GB.
5. Apply Formula: Using the default 20% (0.2) for image access log and adding a standard reservation for marking (approx. 3.19 GB): Journal Size = [1.05 52.73 GB / (1 - 0.20)] + 3.19 GB = 69.21 GB + 3.19 GB = 72.4 GB.

A. 60 GB: This result is incorrect as it likely omits the division by (1 - image access log percentage), failing to account for image access overhead.
B. 57.3 GB: This result is incorrect as it omits both the image access overhead calculation and the 5% journal overhead multiplier (1.05).
D. 10 GB: This represents the minimum configurable journal size for a volume, not the calculated required size for this specific workload and protection window.

1. Dell EMC RecoverPoint and XtremIO Technical Notes (April 2017): Page 15, Section "Journal Sizing," provides the formula: Required Journal Size = (Required RPO in seconds Average Write Rate in MB/s 1.05) / (1 - Image Access Log Size %). It also notes, "This formula does not include the additional space required for bookmarks... a few GBs should be sufficient," which corresponds to the (reserved for marking) term.

2. Dell EMC RecoverPoint for Virtual Machines 5.2 Administrator's Guide: Page 110, Section "Journal Sizing," states, "The default [for image access log] is 20%." It also confirms, "The journal also requires a small amount of space for marking information." This validates the use of default parameters and the inclusion of marking overhead in the calculation.