DAC configuration defaults

Default settings for a Data Availability Committee (AnyTrust) chain as defined in the Arbitrum Chain SDK.

• src/prepareChainConfig.ts
• src/prepareNodeConfig.ts
• src/types/NodeConfig.generated.ts

Nitro v3.10.0 renamed these config keys

As of Nitro v3.10.0, the node-side AnyTrust keys moved:

• node.data-availability.* is deprecated in favor of node.da.anytrust.*
• das-rpc-client was renamed to rpc-client (with the server URL under its rpc.url key)
• node.da-provider moved to node.da.external-provider
• node.batch-poster.das-retention-period was renamed to node.batch-poster.anytrust-retention-period
• node.batch-poster.max-size was deprecated in favor of node.batch-poster.max-calldata-batch-size (calldata batches) and node.da.anytrust.max-batch-size (AnyTrust batches).
• The node no longer accepts sequencer-inbox-address or parent-chain-node-url in its DA section — those settings now exist only as --parent-chain.* flags of the standalone anytrustserver, and a Nitro v3.10.0+ node fails to start when they are present. The reference tables below use the new paths; configs generated by the Arbitrum Chain SDK (shown in the next section) may still use the legacy names until the SDK types are regenerated.

Chain config defaults

Set at rollup creation time.

{
  "arbitrum": {
    "EnableArbOS": true,
    "AllowDebugPrecompiles": false,
    "DataAvailabilityCommittee": false,
    "InitialArbOSVersion": 51,
    "GenesisBlockNum": 0,
    "MaxCodeSize": 24576,
    "MaxInitCodeSize": 49152
  }
}

To enable DAC, override DataAvailabilityCommittee to true at deployment:

prepareChainConfig({
  chainId: 12345,
  arbitrum: {
    InitialChainOwner: '0x...',
    DataAvailabilityCommittee: true,
  },
});

Node config defaults (when DAC is enabled)

Generated by prepareNodeConfig() when chainConfig.arbitrum.DataAvailabilityCommittee is true.

{
  "node": {
    "data-availability": {
      "enable": true,
      "sequencer-inbox-address": "<from coreContracts>",
      "parent-chain-node-url": "<from parentChainRpcUrl>",
      "rest-aggregator": {
        "enable": true,
        "urls": ["http://localhost:9877"]
      },
      "rpc-aggregator": {
        "enable": true,
        "assumed-honest": 1,
        "backends": "[{\"url\":\"http://localhost:9876\",\"pubkey\":\"YAAA...AAA==\"}]"
      }
    },
    "batch-poster": {
      "enable": true,
      "max-size": 90000,
      "parent-chain-wallet": {
        "private-key": "<batchPosterPrivateKey>"
      }
    }
  }
}

Full default values reference

Every DAC-related setting with its documented default, organized by config section.

node.da.anytrust

Key	Default	Description
enable	false	Enable AnyTrust Data Availability mode
max-batch-size	1000000 (1 MB)	Maximum compressed batch size for AnyTrust DA
panic-on-error	false	Fail immediately on DAS errors (not recommended)
request-timeout	5s	Timeout for Store requests

The parent chain connection settings (parent-chain.node-url, parent-chain.connection-attempts with default 15, and parent-chain.sequencer-inbox-address) are flags of the standalone anytrustserver only — refer to How to deploy a DAS.

node.da.anytrust.rest-aggregator

Key	Default	Description
enable	false	Enable REST retrieval of batch data
max-per-endpoint-stats	20	Latency/success-rate stats entries per endpoint
online-url-list	—	URL to a remote list of REST DAS endpoint URLs
online-url-list-fetch-interval	1h0m0s	How often to re-fetch the online URL list
strategy	simple-explore-exploit	Endpoint selection strategy
strategy-update-interval	10s	How often to refresh strategy with latency/error data
urls	[]	Static list of REST DAS endpoint URLs
wait-before-try-next	2s	Time before trying the next set of REST endpoints

node.da.anytrust.rest-aggregator.simple-explore-exploit-strategy

Key	Default	Description
exploit-iterations	1000	Consecutive GetByHash calls using best-latency endpoints before switching to explore
explore-iterations	20	Consecutive GetByHash calls using random endpoints before switching to exploit

node.da.anytrust.rest-aggregator.sync-to-storage

Key	Default	Description
delay-on-error	1s	Wait time before retrying after sync error
eager	false	Eagerly sync batch data using L1 as index (vs lazy)
eager-lower-bound-block	—	Starting L1 block for eager sync (only if no prior state)
ignore-write-errors	true	Log-only on write failures during sync
parent-chain-blocks-per-read	100	Max L1 blocks to read per eager sync poll
retention-period	360h0m0s	How long to retain synced data
state-dir	—	Directory to persist sync progress
sync-expired-data	true	Sync expired data (needed for mirror configs)

node.da.anytrust.rpc-aggregator

Key	Default	Description
assumed-honest	—	H value; required signatures K = N + 1 - H
backends	null	JSON array of {url, pubkey} objects. The aggregator assigns each backend a signersMask of 1 << i based on its index in the array, so member order must match the position of each public key in the onchain keyset.
enable	false	Enable RPC storage of batch data (Batch Poster only)

node.da.anytrust.rpc-aggregator.rpc-client

Key	Default	Description
enable-chunked-store	true	Send data to DAS in chunks instead of all at once
rpc.url	self-auth	DAS server URL; overridden at runtime by each backends[].url entry

node.da.anytrust.rpc-aggregator.rpc-client.data-stream

Key	Default	Description
max-store-chunk-body-size	5242880 (5 MB)	Maximum HTTP body size per chunk

node.da.anytrust.rpc-aggregator.rpc-client.data-stream.rpc-methods

Key	Default	Description
finalize-stream	das_commitChunkedStore	RPC method to finalize a chunked store session
start-stream	das_startChunkedStore	RPC method to initiate a chunked store session
stream-chunk	das_sendChunk	RPC method to send a data chunk

node.batch-poster (DAC-relevant settings)

Key	Default	Description
anytrust-retention-period	360h0m0s	Period DASes retain stored batches in AnyTrust mode
disable-dap-fallback-store-data-on-chain	false	If true, disables fallback to onchain batch posting when DA fails
enable	false	Enable batch posting
max-calldata-batch-size	100000	Maximum estimated compressed calldata batch size (bytes); replaces the deprecated max-size
error-delay	10s	Delay after batch posting error before retry
extra-batch-gas	50000	Extra gas added to batch posting estimate
max-delay	1h0m0s	Maximum batch posting delay
max-empty-batch-delay	72h0m0s	Maximum delay before posting an empty batch
poll-interval	10s	Interval to check for ready batches
check-batch-correctness	true	Verify batch against inbox multiplexer
compression-level	11	Batch compression level
l1-block-bound-bypass	1h0m0s	Post even if outside L1 bounds, within this margin
delay-buffer-always-updatable	true	Always treat delay buffer as updatable
delay-buffer-threshold-margin	25	Blocks before delay buffer threshold to post batch

node.da.external-provider (newer DAProvider interface)

Key	Default	Description
enable	false	Enable DAProvider client
store-rpc-method	daprovider_store	Single-shot store RPC method name
use-data-streaming	false	Use chunked streaming protocol for large payloads
with-writer	false	DAProvider server supports writer interface

node.da.external-provider.data-stream

Key	Default	Description
max-store-chunk-body-size	5242880 (5 MB)	Maximum HTTP body size per chunk

node.da.external-provider.data-stream.rpc-methods

Key	Default	Description
finalize-stream	daprovider_commitChunkedStore	RPC method to finalize a chunked store session
start-stream	daprovider_startChunkedStore	RPC method to initiate a chunked store session
stream-chunk	daprovider_sendChunk	RPC method to send a data chunk

node.da.external-provider.rpc

Key	Default	Description
arg-log-limit	2048	Limit size of arguments in log entries
retries	3	Retries on failure (0 = one attempt)
retry-errors	websocket: close.*|dial tcp .*|.*i/o timeout|.*connection reset by peer|.*connection refused	Regex for auto-retried errors
websocket-message-size-limit	268435456 (256 MB)	WebSocket message size limit

SDK-applied defaults(prepareNodeConfig)

When prepareNodeConfig() detects DataAvailabilityCommittee: true, it applies these concrete values. Source: src/prepareNodeConfig.ts:158-182

Setting	Value Applied	Notes
data-availability.enable	true	Overrides the false default
data-availability.sequencer-inbox-address	coreContracts.sequencerInbox	From deployment output
data-availability.parent-chain-node-url	parentChainRpcUrl	From params
rest-aggregator.enable	true	Overrides the false default
rest-aggregator.urls	["<dasServerUrl>:9877"]	Falls back to http://localhost:9877
rpc-aggregator.enable	true	Overrides the false default
rpc-aggregator.assumed-honest	1	Single honest member (dev default)
rpc-aggregator.backends	JSON with 1 backend	URL at <dasServerUrl>:9876
batch-poster.enable	true	—
batch-poster.max-size	90000	Lower than the NodeConfig default of 100000