Open Stack

Just an FYI that might be the reason for the 14400:

1440 is the number of minutes in a day.  14400 would be tenths of minutes in a day of number of 6second chunks (huh???)

So, the number was picked to divide files in human logical, not computer logical chunks.

--Rocky

-----Original Message-----
From: gordon chung [mailto:gord at live.ca] 
Sent: Thursday, July 28, 2016 3:05 PM
To: openstack-dev at lists.openstack.org
Subject: [openstack-dev] [gnocchi] typical length of timeseries data

hi folks,

this is probably something to discuss on ops list as well eventually but 
what do you think about shrinking the max size of timeseries chunks from 
14400 to something smaller? i'm curious to understand what the length of 
the typical timeseries is. my main reason for bringing this up is that 
even our default 'high' policy doesn't reach 14400 limit so it at most 
will only split into two, partially filled objects. as we look to make a 
more efficient storage format for v3(?) seems like this may be an 
opportunity to change size as well (if necessary)

14400 points roughly equals 128KB object which is cool but maybe we 
should target something smaller? 7200points aka 64KB? 3600 points aka 
32KB? just for reference our biggest default series is 10080 points 
(1min granularity over week).

that said 128KB (at most) might not be that bad from read/write pov and 
maybe it's ok to keep it at 14400? i know from the test i did earlier, 
the time requirement to read/write increases linearly (7200 point object 
takes roughly half time of 14400 point object)[1]. i think the main item 
is we don't want it too small that we're updating multiple objects at a 
time.

[1] http://www.slideshare.net/GordonChung/gnocchi-profiling-v2/25

cheers,

-- 
gord
__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev