Error map
WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always' MongoDB startup: WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'. We suggest setting it to 'never'
MongoDB · layer 5, Data
Centre: this error. First ring: errors it is linked with (8). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (8)
MongoDB: WiredTiger error (28) [...] No space left on device / Fatal assertion 28558 ... disk full
MongoDB ran out of disk space on the data volume and stopped or refuses writes.
Redis: # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis
THP is enabled, which can cause latency spikes and high memory usage with Redis.
MongoServerSelectionError: Could not connect to any servers in your MongoDB Atlas cluster. One common reason is that you're trying to access the database from an IP that isn't whitelisted
Atlas rejects connections from IP addresses that aren't in the project's Network Access list.
MongoServerError: bad auth : Authentication failed. (Atlas user / special characters in password)
Atlas rejected the username/password in the connection string.
MongoDB: Out of memory: Killed process (mongod) — WiredTiger cache + queries exhausted RAM
The Linux OOM killer terminated `mongod` because the host ran out of memory.
MongoServerError: Exceeded memory limit for $group, but didn't allow external sort. Pass allowDiskUse:true to opt in
An aggregation stage needed more than 100 MB of RAM and spilling to disk wasn't enabled.
MongoServerError: BSONObj size: 17825792 (0x1100000) is invalid. Size must be between 0 and 16793600(16MB)
A single document (or an aggregation result row) grew past MongoDB's 16 MB limit.
MongoDB: WARNING: soft rlimits too low. Number of files is 1024, should be at least 64000 / Too many open files
The OS file-descriptor limit for `mongod` is too low, causing connection or file errors under load.
Two steps away (24)
Pod stuck ContainerCreating: MountVolume.SetUp failed / Unable to attach or mount volumes: timed out waiting for the condition
The kubelet couldn’t mount one of the pod’s volumes, so the pod stays in ContainerCreating.
Multi-Attach error for volume: Volume is already exclusively attached to one node and can't be attached to another
A ReadWriteOnce volume (EBS, Azure Disk, PD) is still attached to another node, so the new pod on a different node can’t use it.
PersistentVolumeClaim stuck in Pending (no persistent volumes available / waiting for first consumer)
The PVC hasn’t been bound to a volume, so pods using it can’t be scheduled.
Redis: Client id=12 addr=10.0.0.5:51234 scheduled to be closed ASAP for overcoming of output buffer limits
A client (often a slow subscriber or a replica) couldn't read data fast enough, so Redis disconnected it to protect memory.
Redis: INFO memory — mem_fragmentation_ratio:2.8 (RSS much larger than used_memory)
The process uses far more RSS than the data size, due to allocator fragmentation or deleted-but-not-returned memory.
Redis: (error) BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE
A long-running Lua script (or function) blocks the single-threaded server, so other commands are rejected.
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
Error [ERR_STREAM_PREMATURE_CLOSE]: Premature close
A stream ended or was destroyed before it finished — often a client disconnect or upstream aborting a download.
TypeError: fetch failed (cause: ConnectTimeoutError / ECONNREFUSED / UND_ERR)
Node’s built-in fetch (undici) couldn’t complete the request; the real reason is in error.cause.
MongooseError: Operation `users.find()` buffering timed out after 10000ms
Mongoose queued a query waiting for a connection that never opened.
MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
The MongoDB driver couldn’t find a reachable server for the connection string.
MongoServerError: E11000 duplicate key error collection: db.users index: email_1 dup key
An insert/update violated a unique index in MongoDB.
Kubernetes: OOMKilled (exit code 137)
The container used more memory than its limit, and the kernel killed it.
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
Killed / Out of memory: Killed process (Linux OOM killer)
The kernel ran out of memory and killed a process to recover — the program just prints “Killed” (exit code 137).
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
The V8 heap hit its limit — a large build (webpack, tsc, Next.js) needs more memory, or the app leaks.
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added
More than 10 listeners were added to one event — often a leak where listeners are added repeatedly.
CastError: Cast to ObjectId failed for value "x" (type string) at path "_id"
A value that isn’t a valid 24-hex-character ObjectId was used in an _id query.
Too many open files (EMFILE)
The process hit its file-descriptor limit — sockets, files and pipes all count.
ValidationError: User validation failed: email: Path `email` is required.
A document failed Mongoose schema validation before saving.
Lambda: Request must be smaller than 6291456 bytes for the InvokeFunction operation (RequestEntityTooLargeException)
The event payload (or response) is over Lambda’s 6 MB synchronous limit (256 KB for async invocations).
Lambda: Unzipped size must be smaller than 262144000 bytes
The function code plus layers exceed Lambda’s 250 MB unzipped limit for zip deployments.
fork: retry: Resource temporarily unavailable (process/thread limit)
The user or container hit its maximum number of processes/threads (ulimit -u, pids cgroup), so new processes can’t be created.
mongod: Process exited with status 14 — Exception in initAndListen: IllegalOperation: Attempted to create a lock file on a read-only directory
`mongod` couldn't start because the data directory or log/socket file isn't writable or already locked.
Map another error
Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError