diff --git a/services/clsi/app.js b/services/clsi/app.js
index 77ab922987..8dd8a8cbf3 100644
--- a/services/clsi/app.js
+++ b/services/clsi/app.js
@@ -412,8 +412,9 @@ if (!module.parent) {
 module.exports = app
 
 setInterval(() => {
-  ProjectPersistenceManager.refreshExpiryTimeout()
-  ProjectPersistenceManager.clearExpiredProjects()
+  ProjectPersistenceManager.refreshExpiryTimeout(() => {
+    ProjectPersistenceManager.clearExpiredProjects()
+  })
 }, tenMinutes)
 
 function __guard__(value, transform) {
diff --git a/services/clsi/app/js/ProjectPersistenceManager.js b/services/clsi/app/js/ProjectPersistenceManager.js
index d0fd4c2439..ca903f4410 100644
--- a/services/clsi/app/js/ProjectPersistenceManager.js
+++ b/services/clsi/app/js/ProjectPersistenceManager.js
@@ -21,34 +21,45 @@ const logger = require('logger-sharelatex')
 const oneDay = 24 * 60 * 60 * 1000
 const Settings = require('settings-sharelatex')
 const diskusage = require('diskusage')
+const { callbackify } = require('util')
 
-module.exports = ProjectPersistenceManager = {
-  EXPIRY_TIMEOUT: Settings.project_cache_length_ms || oneDay * 2.5,
-
-  refreshExpiryTimeout(callback) {
-    if (callback == null) {
-      callback = function (error) {}
-    }
-    diskusage.check('/', function (err, stats) {
-      if (err) {
-        logger.err({ err: err }, 'error getting disk usage')
-        return callback(err)
-      }
+async function refreshExpiryTimeout() {
+  const paths = [
+    Settings.path.compilesDir,
+    Settings.path.outputDir,
+    Settings.path.clsiCacheDir
+  ]
+  for (const path of paths) {
+    try {
+      const stats = await diskusage.check(path)
       const lowDisk = stats.available / stats.total < 0.1
+
       const lowerExpiry = ProjectPersistenceManager.EXPIRY_TIMEOUT * 0.9
       if (lowDisk && Settings.project_cache_length_ms / 2 < lowerExpiry) {
         logger.warn(
           {
-            stats: stats,
+            stats,
             newExpiryTimeoutInDays: (lowerExpiry / oneDay).toFixed(2)
           },
           'disk running low on space, modifying EXPIRY_TIMEOUT'
         )
         ProjectPersistenceManager.EXPIRY_TIMEOUT = lowerExpiry
+        break
       }
-      callback()
-    })
+    } catch (err) {
+      logger.err({ err, path }, 'error getting disk usage')
+    }
+  }
+}
+
+module.exports = ProjectPersistenceManager = {
+  EXPIRY_TIMEOUT: Settings.project_cache_length_ms || oneDay * 2.5,
+
+  promises: {
+    refreshExpiryTimeout
   },
+
+  refreshExpiryTimeout: callbackify(refreshExpiryTimeout),
   markProjectAsJustAccessed(project_id, callback) {
     if (callback == null) {
       callback = function (error) {}
diff --git a/services/clsi/test/unit/js/ProjectPersistenceManagerTests.js b/services/clsi/test/unit/js/ProjectPersistenceManagerTests.js
index 5fb1827206..e60de54ff3 100644
--- a/services/clsi/test/unit/js/ProjectPersistenceManagerTests.js
+++ b/services/clsi/test/unit/js/ProjectPersistenceManagerTests.js
@@ -28,7 +28,12 @@ describe('ProjectPersistenceManager', function () {
         './CompileManager': (this.CompileManager = {}),
         diskusage: (this.diskusage = { check: sinon.stub() }),
         'settings-sharelatex': (this.settings = {
-          project_cache_length_ms: 1000
+          project_cache_length_ms: 1000,
+          path: {
+            compilesDir: '/compiles',
+            outputDir: '/output',
+            clsiCacheDir: '/cache'
+          }
         }),
         './db': (this.db = {})
       }
@@ -40,7 +45,7 @@ describe('ProjectPersistenceManager', function () {
 
   describe('refreshExpiryTimeout', function () {
     it('should leave expiry alone if plenty of disk', function (done) {
-      this.diskusage.check.callsArgWith(1, null, {
+      this.diskusage.check.resolves({
         available: 40,
         total: 100
       })
@@ -54,7 +59,7 @@ describe('ProjectPersistenceManager', function () {
     })
 
     it('should drop EXPIRY_TIMEOUT 10% if low disk usage', function (done) {
-      this.diskusage.check.callsArgWith(1, null, {
+      this.diskusage.check.resolves({
         available: 5,
         total: 100
       })
@@ -66,7 +71,7 @@ describe('ProjectPersistenceManager', function () {
     })
 
     it('should not drop EXPIRY_TIMEOUT to below 50% of project_cache_length_ms', function (done) {
-      this.diskusage.check.callsArgWith(1, null, {
+      this.diskusage.check.resolves({
         available: 5,
         total: 100
       })
@@ -78,10 +83,7 @@ describe('ProjectPersistenceManager', function () {
     })
 
     it('should not modify EXPIRY_TIMEOUT if there is an error getting disk values', function (done) {
-      this.diskusage.check.callsArgWith(1, 'Error', {
-        available: 5,
-        total: 100
-      })
+      this.diskusage.check.throws(new Error())
       this.ProjectPersistenceManager.refreshExpiryTimeout(() => {
         this.ProjectPersistenceManager.EXPIRY_TIMEOUT.should.equal(1000)
         done()