Michael Schuster writes:
> IHAC who is using a very similar test (cp -pr /zpool1/Studio11
> /zpool1/Studio11.copy) and is seeing behaviour similar to what we've
> seen described here; BUT since he's using a single-CPU box (SunBlade
> 1500) and has a single disk in his pool, every time the CPU goes into
> "100%-mode", interactive usability is reduced to zero for 1-2
> seconds. This is of course undesirable.
>
> + Do we have any bug IDs or RFEs addressing this?
> + Is there any tuning the customer can try (he's willing to do anything with
> the machine, apart from donating it to me :-)? (we've already tried "echo
> txg_time/W1 | mdb -kw", with no improvement - on the contrary, machine
> returned to "usable" state hardly at all).
> + has customer (and I) missed a constraint about when/where to deploy zfs?
>
> thx
> Michael
>
>
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What is the desired behavior ?
The workload (cp with compression) overloads the single
CPU. Response time is bound to be affected.
I am not sure how we could get compression to run at a low
priority level, holding up write syscalls.
I suggest to Buy a second CPU or turn off compression.
With even with a second CPU, once compression becomes MT-hot,
he might well suffer again. Maybe we need
compression=on|off|iflightcpuload
-r
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