Difference between revisions of "I/O sniffing"
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| + | I coined an expression I/O sniffing for listening to the system at block level like this: | ||
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| + | initiator XYZ requests block 4711 from device 0815 | ||
| + | initiator BLA writes block 1234 to device 9876 | ||
| + | |||
You can do I/O sniffing using the command blktrace. blktrace will show you every request that goes to the disk. | You can do I/O sniffing using the command blktrace. blktrace will show you every request that goes to the disk. | ||
Revision as of 18:03, 23 December 2013
I coined an expression I/O sniffing for listening to the system at block level like this:
initiator XYZ requests block 4711 from device 0815 initiator BLA writes block 1234 to device 9876
You can do I/O sniffing using the command blktrace. blktrace will show you every request that goes to the disk.
Example:
# blktrace -d /dev/sdg -o - | blkparse -i - [...] 8,96 7 106 0.373952974 11364 D W 0 + 8 [kworker/7:2] 8,96 7 107 0.374456639 47 C W 0 + 8 [0]
The RWBS(D) field can be a combination of
R : Read W : Write D : Block discard B : Barrier operation S : Synchronous operations
