Oak 2025h2 Storage Limits

[Matthew McPherrin]

Hello CT Folks,

Let's Encrypt is concerned about the possibility of our Oak 2025h2 shard hitting the 16TiB table-size limit which previously killed our TestFlume log.

We believe that we should have enough space to proceed until our previously announced date to mark the shard read-only. The LeafData table is currently at 13TiB.

However, if at all possible, we'd like to ask clients to avoid submitting to Oak 2025h2.  For 90 day certificates, Oak 2026h1 overlaps and is currently "in range" for submission. Let's Encrypt has already stopped submitting to this shard.

Thanks,
Matthew McPherrin
Let's Encrypt