I recently ran into an issue where my ESXi 5.5 hosts started randomly dropping off the network and the only way to get them back was to reboot them. In going through the logs below is the findings of what happened and why:
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_attn_int_deasserted3:4816(vmnic0)]MC assert!
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_mc_assert:937(vmnic0)]XSTORM_ASSERT_LIST_INDEX 0x2
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_mc_assert:951(vmnic0)]XSTORM_ASSERT_INDEX 0x0 = 0x00020000 0x00010017 0x05aa05b4 0x00010053
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_mc_assert:965(vmnic0)]Chip Revision: everest3, FW Version: 7_10_51
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_attn_int_deasserted3:4822(vmnic0)]driver assert
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_panic_dump:1140(vmnic0)]begin crash dump —————–
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_panic_dump:1150(vmnic0)]def_idx(0xfbd2) def_att_idx(0xa) attn_state(0x1) spq_prod_idx(0xcf) next_stats_cnt(0xdd33)
2015-06-12T16:23:54.454Z cpu17:33604)<3>bnx2x: [bnx2x_panic_dump:1155(vmnic0)]DSB: attn bits(0x0) ack(0x1) id(0x0) idx(0xa)
This is a low-level driver crash caused by a MC assert without any other hypervisor problems at the time. The bnx2x card then begins a crash dump and resets itself. The data from the crash dump of the adapter has data but it appears to only be useful to Broadcom/Qlogic. At the end of the crash dump it shows that the card gets reset.