Which statement best explains why London users report faster access after the first file open, but initial reads are slow?

Which statement best explains why London users report faster access after the first file open, but initial reads are slow?

• A. The first read retrieves data directly from the origin before caching it locally.
• B. FlexCache volumes always replicate the entire dataset from the origin before serving clients.
• C. The FlexCache volume cannot store read data locally; all reads traverse the WAN.
• D. The origin volume must be replicated via SnapMirror before FlexCache can serve data.

Answer: (A)

FlexCache uses edge caching to speed repeated access. When a file is opened for the first time, the cache at the London site doesn’t yet have those blocks, so the read is forwarded to the origin over the WAN. The data then gets stored in the local cache. Because the data is now cached locally, subsequent reads for that same file are served from the fast local cache rather than traveling back to the origin, so access becomes much quicker for London users. This on-demand caching behavior explains the pattern: slow initial reads, fast follow-up reads. Other options aren’t correct because they imply behavior that FlexCache doesn’t use: it doesn’t pre-replicate the entire dataset before serving clients; it stores read data locally only after it’s requested; and it doesn’t require SnapMirror replication for FlexCache to serve data (SnapMirror is for data protection/continuity, not a prerequisite for initial caching).

FlexCache uses edge caching to speed repeated access. When a file is opened for the first time, the cache at the London site doesn’t yet have those blocks, so the read is forwarded to the origin over the WAN. The data then gets stored in the local cache. Because the data is now cached locally, subsequent reads for that same file are served from the fast local cache rather than traveling back to the origin, so access becomes much quicker for London users. This on-demand caching behavior explains the pattern: slow initial reads, fast follow-up reads.

Other options aren’t correct because they imply behavior that FlexCache doesn’t use: it doesn’t pre-replicate the entire dataset before serving clients; it stores read data locally only after it’s requested; and it doesn’t require SnapMirror replication for FlexCache to serve data (SnapMirror is for data protection/continuity, not a prerequisite for initial caching).