Slow performance using linkwalk, help wanted

Ryan Tilder rtilder at basho.com
Mon Nov 8 17:43:24 EST 2010


Hi, Jan.  Your description of the behaviour you're seeing below is
frequently the result of slow access times to data on disk due to low
spindle count for a given data set.  Can you tell me the hardware
specifications of the disks in each of the machines in the Riak ring?
 Primarily the number of disks, their capacity in GB or TB, their spindle
speed, any on disk buffer they might have, and whether or not they're all
the same hardware model?[1]

One other question that might be relate: is there any other software of note
running on the hardware?  i.e. Riak running on multi-tenant hardware in a
Solaris Zone while another DB is running in a separate Zone on the same
hardware, another disk seek heavy daemon running on the same machine, etc.

--Ryan

1. If you don't know the above, you can get a lot of information from the
"prtconf -v | more" command and just search for the work "disk".  The model
number(s) for the relevant disks is enough that we can hunt down the
technical specs quickly enough.

On Mon, Nov 8, 2010 at 12:44 PM, Jan Buchholdt <jbu at trifork.com> wrote:

> Another information is that the first time I do a link walk (using curl) on
> a total idle cluster it takes 2.71 second for a person with 363 documents.
> If I repeat the request it takes 319 milliseconds. I would expect that the
> performance would be almost the same.
>
> If I run my performance test with 20 treads, that randomly pick a Person
> from 5 millions, the minimum time is 2.8s, average 6.7s, 90% 8.9s and max
> 12.4s.
>
>
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