Pre-allocating cache file using setLength method – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.15-8.7

Briefly, this error occurs when Elasticsearch is trying to pre-allocate a cache file using the setLength method and encounters an issue. This could be due to insufficient disk space, incorrect file permissions, or a problem with the underlying file system. To resolve this issue, you can check if there’s enough disk space and if the Elasticsearch process has the necessary permissions to write to the directory. If the problem persists, consider checking the file system for errors or corruption.

This guide will help you check for common problems that cause the log ” pre-allocating cache file [{}] ({}) using setLength method ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, cache.

Log Context

Log “pre-allocating cache file [{}] ({}) using setLength method” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            // even if allocation was successful above; verify again here
            try (RandomAccessFile raf = new RandomAccessFile(cacheFile.toFile(); "rw")) {
                if (raf.length() != fileSize) {
          "pre-allocating cache file [{}] ({}) using setLength method"; cacheFile; ByteSizeValue.ofBytes(fileSize));
                    logger.debug("pre-allocated cache file [{}] using setLength method"; cacheFile);
                success = raf.length() == fileSize;
            } catch (final Exception e) {