Release N.2.9.7-alpha1-dev-sync-performance-20260909

Arweave 2.9.7-alpha1-dev-sync-performance-20260909 Release Notes

This is a development prerelease containing changes under active
development. It may not work correctly, and some changes may not be included
in a regular release.

Based on Arweave 2.9.7-alpha1, this release introduces adaptive per-peer sync
concurrency, better balancing across storage modules, localized backpressure
for slow peers and disks, and lower sync-record snapshot memory use.

Configuration changes

• sync_jobs and [sync, jobs] are removed. To limit your sync rate, use
  [sync, max_download_rate] or sync_max_download_rate in bytes per second,
  or infinity (the default). A value of 0
  disables syncing.
• [sync, max_concurrent_peer_scans] and the legacy
  data_discovery_max_concurrent_peer_scans option have been removed without
  replacement. Discovery concurrency is automatic.
• [sync, cache_size_limit] is now [sync, cache_size], measured in MiB.
• [network, client, http, connections_per_peer] is new and defaults to 8.
  Most operators should leave it unchanged.

Other option changes are below. Legacy flat names remain supported and unchanged.

Old option	New option
[disk_pool, jobs]	[disk_pool, workers]
[gossip, header_sync_jobs]	[gossip, header, workers]
[gossip, header_cache_size]	[gossip, header, cache_size]
[network, server, tcp, ...] socket settings	[network, server, socket, ...]
[network, client, tcp, ...]	[network, client, socket, ...]
Server listener, connection, and idle settings	[network, server, http, ...]
Server shutdown and socket-backend settings	Nested shutdown and socket paths

Replica 2.9 guidance

Preparing entropy first remains recommended: start with
[sync, max_download_rate] set to 0, wait for preparation, then restart with
a positive rate or infinity.

Metrics and compatibility

Custom dashboards may need updating. Key replacements are
chunk_write_rate_bytes_per_second → store_drain_rate_bytes_per_second,
peer_interval_cache_* → chunk_interval_cache_*, and data_discovery →
sync_discovery_peers. New sync_peer_*, sync_tasks_by_*, sync_claimed_*,
and sync_sweep_offset metrics describe scheduler behavior.

If downgrading to 2.9.7-alpha1 after running this
release, stop the node and remove the peers file from data_dir; the older
release cannot read the new peer-performance cache format, and the cache will
be rebuilt automatically.