You have just allocated four 3TB LUNs from a Hitachi Unified Storage System to a set of ESX 4.x servers. The VMware administrator can see volumes that are assigned to the servers from an older…

Question

Options

• AThe FC switch ports need to be disabled/enabled to force the HBAs to re-login to the fabric.
• BThis a newer storage array with an older version of ESX so the HBA drivers need to be updated.
• CESX 4.x servers cannot recognize volumes that are 2TB or larger.
• DThe rescan function in VMware is not working, so both servers need to be rebooted.

• A
  8% (2)
• B
  4% (1)
• C
  84% (21)
• D
  4% (1)

Explanation

ESX 4.x (and earlier) has a hard limit of 2TB - 512 bytes per LUN due to its reliance on MBR partitioning and VMFS3, so the 3TB LUNs are simply invisible to the hypervisor regardless of zoning or rescan status - this limitation was not resolved until ESXi 5.0 introduced VMFS5 with GPT support. Option A is wrong because FC port cycling affects fabric login for all volumes, yet the older array's volumes remain visible, which rules out a fabric connectivity issue. Option B is wrong because the problem isn't driver compatibility with newer hardware - it's a fundamental filesystem/partition-table ceiling that no driver update can fix. Option D is wrong because a manual rescan (not a reboot) is the standard method to discover new LUNs, and neither action would help when the OS architecturally cannot address volumes above 2TB.

Memory tip: Think "ESX 4 can't do 2TB-plus" - the version number (4) is smaller than 5, just like its LUN size ceiling is smaller than what modern storage can provide. If you see 3TB LUNs and ESX 4.x, the answer is always the size limit.

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