ERR max number of clients reached Redis Origin: Data Last updated 5 Nov 2026

Redis: ERR max number of clients reached

Redis hit its maxclients limit (default 10000, lower if the OS limit is low), so new connections are refused.

Exact message you may see ERR max number of clients reachedReplyError: ERR max number of clients reachedredis.exceptions.ConnectionError: max number of clients reachedError: ERR max number of clients reached
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Seen on: Redis Linux Node.js

Meaning

Find who holds connections: CLIENT LIST, INFO clients. Typical causes are connection leaks (creating a client per request), no pooling, many app instances × pool size, or ulimit -n lowering the effective limit. Reuse a single client/pool, close connections, and raise maxclients plus OS limits if justified.

Common causes

  • New client created per request, never closed
  • Pool sizes × instances exceed maxclients
  • Low ulimit -n (effective maxclients lowered)
  • Serverless functions opening connections on every invocation
  • Zombie connections after crashes

⚡ Quick fix

  1. Reuse one client/pool per process
  2. CLIENT LIST to identify leaks; CLIENT KILL idle ones
  3. Raise maxclients and the OS file-descriptor limit

Detailed fix by platform

Linux

  1. redis-cli INFO clients; redis-cli CLIENT LIST | awk '{print $2}' | cut -d= -f2 | cut -d: -f1 | sort | uniq -c | sort -rn | head

How to diagnose

  1. Count — connected_clients?
  2. Source — Which IPs?
  3. Limit — maxclients vs ulimit?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Data. Errors that are often confused with or caused by this one (click to open):

BullMQ: Missing lock for job / job stalled more than allowable limit — BullMQ: Error: Missing lock for job 42. moveToFinished / job stalled more than allowable limit (Redis)BullMQ: Missing lock …BUSY Redis is busy running a script — Redis: (error) BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE (Redis)BUSY Redis is busy ru…Celery with Redis: tasks run twice (visibility_timeout) — Celery: Task executed twice / Restoring unacked messages — Redis broker visibility_timeout shorter than task ETA (Redis)Celery with Redis: ta…Client output buffer limit reached (scheduled to be closed) — Redis: Client id=12 addr=10.0.0.5:51234 scheduled to be closed ASAP for overcoming of output buffer limits (Redis)Client output buffer …ECONNRESET / Connection reset by peer on idle Redis connection — Redis: Error: read ECONNRESET / redis.exceptions.ConnectionError: Connection reset by peer after idle time (Redis)ECONNRESET / Connecti…EMFILE — Too many open files (EMFILE) (Linux)EMFILEfork: retry: Resource temporarily unavailable — fork: retry: Resource temporarily unavailable (process/thread limit) (Linux)fork: retry: Resource…JedisException: Could not get a resource from the pool — Jedis: redis.clients.jedis.exceptions.JedisException: Could not get a resource from the pool (Redis)JedisException: Could…ERR max n…

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