Re: raid io requests not parallel?

[Jonathan Baccash]

> Each head has to service 1024 write requests (compared to just 512 read
> requests).

By that logic, it would take twice as long for my writes to finish.
Why is it taking 4x as long in my parallel test? I don't think any of
the repliers understood my question. What I want to know is, during a
single direct IO write request, I would expect the raid software to
issue the write request to both disks simultaneously. But the evidence
indicates that isn't what is happening. I would expect a raid-1 write
to take about as long to write a single block as a single write to a
single disk (assuming no other disk activity), because I would expect
two writes to happen concurrently.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/