Pre-allocating cache file bytes using native methods – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.8-8.9

Briefly, this error occurs when Elasticsearch is trying to pre-allocate cache file bytes using native methods but 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 try freeing up disk space, checking and correcting file permissions, or investigating potential issues with the file system. Additionally, ensure that Elasticsearch has the necessary permissions to write to the specified directory.

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

Log Context

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

        try {
            if (prealloactor.useNative()) {
                try (FileOutputStream fileChannel = new FileOutputStream(cacheFile.toFile())) {
                    long currentSize = fileChannel.getChannel().size();
                    if (currentSize 


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