# TranslogException: failed to sync translog for [my_index][0] - java.nio.file.AccessDeniedException: /data/elasticsearch/nodes/0/indices/.../translog/translog-12345.tlog

- **ID:** `elasticsearch/translog-sync-failure`
- **Domain:** elasticsearch
- **Category:** system_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The Elasticsearch process lacks write permissions to the translog file, often due to filesystem permission changes or disk errors.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| elasticsearch 7.17.0 | active | — | — |
| elasticsearch 8.10.0 | active | — | — |
| elasticsearch 8.15.0 | active | — | — |

## Workarounds

1. **Fix permissions on the translog directory: chown -R elasticsearch:elasticsearch /data/elasticsearch/nodes/0/indices/ and ensure the elasticsearch user has write access.** (85% success)
   ```
   Fix permissions on the translog directory: chown -R elasticsearch:elasticsearch /data/elasticsearch/nodes/0/indices/ and ensure the elasticsearch user has write access.
   ```
2. **If disk is full, free up space by removing old indices or increasing disk capacity, then retry sync.** (80% success)
   ```
   If disk is full, free up space by removing old indices or increasing disk capacity, then retry sync.
   ```
3. **As a last resort, close and reopen the index to regenerate translog: POST /my_index/_close then POST /my_index/_open. This may drop uncommitted changes.** (70% success)
   ```
   As a last resort, close and reopen the index to regenerate translog: POST /my_index/_close then POST /my_index/_open. This may drop uncommitted changes.
   ```

## Dead Ends

- **** — The underlying permissions issue persists; the node will fail again when it tries to sync the translog. (90% fail)
- **** — Deleting translog can cause data loss and corrupt the shard; Elasticsearch may refuse to start. (70% fail)
- **** — The new directory may also have permissions issues if not configured correctly. (50% fail)