FileBackedStorageEngine may cause DirectMemory OutOfMemoryError when handling large objects

[ShadowUnderMoon]

Hello,

I am using Ehcache 3 to cache very large objects. When testing the disk cache implementation (FileBackedStorageEngine), I found that file read/write operations are based on FileChannelImpl, which internally uses DirectByteBuffer. As a result, the temporary off-heap memory required can be roughly as large as the serialized object itself.

This can easily lead to exceeding the configured direct memory limit (-XX:MaxDirectMemorySize). On JDK 8, this situation may even trigger a deadlock due to JDK-8054039
.

In contrast, Ehcache 2 uses RandomAccessFile for file operations, which internally allocates memory via JNI malloc and does not encounter the same problem.

My question is: is there any plan to optimize this for large-object scenarios in Ehcache 3? For example, by implementing chunked writes/reads instead of requiring a single large direct buffer.

Environment:

Ehcache version: 3.10.8

JDK: 1.8

OS: Linux

Thanks!