milvus Please ensure your drive supports O_DIRECT

To ensure that your drive supports O_DIRECT, you can follow these steps:

1. Check the kernel version: O_DIRECT support requires a Linux kernel version of 2.4 or higher.

2. Verify if the drive supports direct I/O: Run the following command to check if your drive supports direct I/O:

   cat /sys/block/<drive_name>/queue/discard_granularity
   

   If the command returns a non-zero value, then your drive supports direct I/O.

3. Check the file system: Ensure that the file system on the drive supports O_DIRECT. The ext4 and XFS file systems generally support O_DIRECT.

4. Test O_DIRECT support: You can test if O_DIRECT is supported on your drive by running a simple program that uses the O_DIRECT flag when opening a file. Here's an example C program:

   #include <stdio.h>
   #include <fcntl.h>
   #include <unistd.h>
   
   int main() {
       int fd;
       char buffer[4096];
   
       fd = open("/path/to/file", O_RDONLY | O_DIRECT);
       if (fd < 0) {
           perror("open");
           return 1;
       }
   
       ssize_t bytes_read = read(fd, buffer, sizeof(buffer));
       if (bytes_read < 0) {
           perror("read");
           return 1;
       }
   
       close(fd);
   
       printf("O_DIRECT supported!\n");
       return 0;
   }
   

   Replace /path/to/file with the actual path to a file on your drive. Compile and execute the program. If it runs without errors and prints "O_DIRECT supported!", then your drive supports O_DIRECT.

By following these steps, you can ensure that your drive supports O_DIRECT