Fast I/O in backup driver

NTFSD
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Hey , im working on a small project aimed to provide backup for files being written , do i need to take care of fast i/o as well ? should a fast io pre write be the same as standard IRP based pre write

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FltMgr presents both Fast I/O and IRP based writes as IRP_MJ_WRITE. You can differentiate between the two by checking for the FLTFL_CALLBACK_DATA_FAST_IO_OPERATION flag.

Note that the only real difference in handling them is that you can't pend Fast I/O requests (i.e. return FLT_PREOP_PENDING).

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Hello,

As per my knowledge, For your backup project, consider fast I/O if performance is critical, as it reduces latency and overhead. However, standard IRP-based pre-write operations are more reliable and compatible. Start with IRP for simplicity and stability, adding fast I/O optimizations later if needed. Balance speed with reliability.

I hope this will help you.

Thanks

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If this is a minifilter you (mostly) dont care.

If it isn’t then its an FSD and that seems heavyweight…

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