Red Hat ENTERPRISE LINUX - ONLINE STORAGE RECONFIGURATION GUIDE BETA Informazioni Techniche Scaricare il pdf (Pagina 89)

This will cause the I/O to later fail with a checksum error. This problem is common to all block device

(or file system-based) buffered I/O or mmap(2) I/O, so it is not possible to work around these errors

caused by overwrites.

As such, block devices with DIF/DIX enabled should only be used with applications that use

O _D IR EC T . Such applications should use the raw block device. Alternatively, it is also safe to use

the XFS file system on a DIF/D IX enabled block device, as long as only O _D IR EC T I/O is issued

through the file system. XFS is the only file system that does not fall back to buffered I/O when doing

certain allocation operations.

The responsibility for ensuring that the I/O data does not change after the DIF/DIX checksum has

been computed always lies with the application, so only applications designed for use with

O _D IR EC T I/O and DIF/D IX hardware should use DIF/D IX.

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Red Hat ENTERPRISE LINUX - ONLINE STORAGE RECONFIGURATION GUIDE BETA Informazioni Techniche Pagina 89