Solution if the performance of block devices in the AIX system is poor

Solution if the performance of block devices in the AIX system is poor:
Use the dd command to test the performance of block devices in the AIX system. The test result is 30 MB/s, which is poor.
dd command: dd if=/dev/updisk0 of=/dev/null bs=1024K
Block devices in the AIX system can be used only for the transmission of data with a specified size. In this case, I/Os must pass through the kernel buffer cache. In contrast, raw devices read data from or write data to disks directly bypassing the operating system. In this way, different from block devices, I/O requests will not be split and processed and therefore, performance will not be impacted.
In the AIX operating system, you are advised to use raw devices. A block device is /dev/updisk0 and a raw device is /dev/rupdisk0.

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