For IPv[46] fragmentation reassembly, memory is capped at
net.ipv[46].ip[6]frag_high_thresh
Fragmentation reassembly can fail if this value is set too low; monitor for fragmentation reassembly
and bump value if needed.
Avoid bumping it if assembly failures are correlated with increases in frag_high_thresh; this suggests
that increasing available memory does not help. While correlation is high, tune down the
frag_high_thresh value.
Tunables:
• net.ipv4.ipfrag_high_thresh: number of bytes devoted to IPv4 fragmentation reassembly; default 4MB
• net.ipv6.ip6frag_high_thresh: number of bytes devoted to IPv6 fragmentation reassembly; default 4MB