Recording time taken for disk IO

[Vishal Kher <vi...@gmail.com>]

Hi,

I was wondering if there is a way to measure the disk IO latency at ZK
server for reads/writes performed to the  transaction log and snapshots.  In
case ZK
is experiencing higher transaction latencies it would be useful to
verify whether it is due to disk or network.

We need to add this for debugging our application since we do not have
 ZK logs on dedicated disks.  If the disk IO is not currently monitored, I
was thinking of extending the streams used in FiLeSnap.java and
FileTxnLog.java, and measure the time taken to do the IO.
Does this sound like a good place to measure the latency?
Will it  useful to have this in the tree?

Thanks,
-Vishal

Re: Recording time taken for disk IO

[Benjamin Reed <br...@apache.org>]

measuring these latencies and recording them in the stats structure
would be great! i don't think we need to measure the time to take
snapshots though since they happen outside of the critical path and in
the background.

ben

On Fri, Apr 1, 2011 at 2:46 PM, Vishal Kher <vi...@gmail.com> wrote:
> Hi,
>
> I was wondering if there is a way to measure the disk IO latency at ZK
> server for reads/writes performed to the  transaction log and snapshots.  In
> case ZK
> is experiencing higher transaction latencies it would be useful to
> verify whether it is due to disk or network.
>
> We need to add this for debugging our application since we do not have
>  ZK logs on dedicated disks.  If the disk IO is not currently monitored, I
> was thinking of extending the streams used in FiLeSnap.java and
> FileTxnLog.java, and measure the time taken to do the IO.
> Does this sound like a good place to measure the latency?
> Will it  useful to have this in the tree?
>
> Thanks,
> -Vishal
>