diff --git a/fly.toml b/fly.toml
index 1988b0ea..c941f1d2 100644
--- a/fly.toml
+++ b/fly.toml
@@ -6,3 +6,7 @@ primary_region = "cdg"
 
 [deploy]
   strategy = "rolling"
+
+[mount]
+  source = "spark-evaluate-data"
+  destination = "/var/lib/spark-evaluate/"
\ No newline at end of file
diff --git a/index.js b/index.js
index 1b7e90f1..7da70c3b 100644
--- a/index.js
+++ b/index.js
@@ -5,12 +5,15 @@ import { evaluate } from './lib/evaluate.js'
 import { RoundData } from './lib/round.js'
 import { refreshDatabase } from './lib/platform-stats.js'
 import timers from 'node:timers/promises'
+import fs from 'node:fs/promises'
 
 // Tweak this value to improve the chances of the data being available
 const PREPROCESS_DELAY = 60_000
 
 const EVALUATE_DELAY = PREPROCESS_DELAY + 60_000
 
+const ROUND_BUFFER_PATH = '/var/lib/spark-evaluate/round-buffer.ndjson'
+
 export const startEvaluate = async ({
   ieContract,
   ieContractWithSigner,
@@ -30,6 +33,25 @@ export const startEvaluate = async ({
   const roundsSeen = []
   let lastNewEventSeenAt = null
 
+  let roundBuffer
+  try {
+    roundBuffer = await fs.readFile(ROUND_BUFFER_PATH, 'utf8')
+  } catch (err) {
+    if (err.code !== 'ENOENT') {
+      console.error('CANNOT READ ROUND BUFFER:', err)
+      Sentry.captureException(err)
+    }
+  }
+  if (roundBuffer) {
+    const lines = roundBuffer.split('\n').filter(Boolean)
+    if (lines.length > 1) {
+      rounds.current = new RoundData(JSON.parse(lines[0]))
+      for (const line of lines.slice(1)) {
+        rounds.current.measurements.push(JSON.parse(line))
+      }
+    }
+  }
+
   const onMeasurementsAdded = async (cid, _roundIndex) => {
     const roundIndex = BigInt(_roundIndex)
     if (cidsSeen.includes(cid)) return
@@ -67,7 +89,8 @@ export const startEvaluate = async ({
         roundIndex,
         fetchMeasurements,
         recordTelemetry,
-        logger
+        logger,
+        ROUND_BUFFER_PATH
       })
     } catch (err) {
       console.error('CANNOT PREPROCESS MEASUREMENTS [ROUND=%s]:', roundIndex, err)
@@ -89,6 +112,15 @@ export const startEvaluate = async ({
 
     console.log('Event: RoundStart', { roundIndex })
 
+    try {
+      await fs.writeFile(ROUND_BUFFER_PATH, '')
+    } catch (err) {
+      if (err.code !== 'ENOENT') {
+        console.error('CANNOT DELETE ROUND BUFFER:', err)
+        Sentry.captureException(err)
+      }
+    }
+
     if (!rounds.current) {
       console.error('No current round data available, skipping evaluation')
       return
diff --git a/lib/preprocess.js b/lib/preprocess.js
index 051664b6..2cb7d0ee 100644
--- a/lib/preprocess.js
+++ b/lib/preprocess.js
@@ -6,6 +6,7 @@ import { validateBlock } from '@web3-storage/car-block-validator'
 import { recursive as exporter } from 'ipfs-unixfs-exporter'
 import createDebug from 'debug'
 import pRetry from 'p-retry'
+import fs from 'node:fs/promises'
 
 const debug = createDebug('spark:preprocess')
 
@@ -55,7 +56,8 @@ export const preprocess = async ({
   fetchMeasurements,
   recordTelemetry,
   logger,
-  fetchRetries = 14
+  fetchRetries = 14,
+  ROUND_BUFFER_PATH
 }) => {
   const start = Date.now()
   /** @type import('./typings.js').RawMeasurement[] */
@@ -116,6 +118,10 @@ export const preprocess = async ({
   logger.log('Retrieval Success Rate: %s%s (%s of %s)', Math.round(100 * okCount / total), '%', okCount, total)
 
   round.measurements.push(...validMeasurements)
+  await fs.appendFile(
+    ROUND_BUFFER_PATH,
+    validMeasurements.map(m => JSON.stringify(m)).join('\n') + '\n'
+  )
 
   recordTelemetry('preprocess', point => {
     point.intField('round_index', roundIndex)