Creates too slow, but I/O util is below 20%
I'm trying to verify that graphite will handle 100k metrics per minute properly, so I've made a script posting 1666 metrics per second to a single carbon-cache instance on localhost.
The problem is that creates are really slow, I started running this script every second "find /mnt/whisper/ -type f | wc -l >> carbon-counts" and it turned out that only about 10 new metrics are created. At the same time "iostat -dxk 10" shows:
ubuntu@
Linux 3.2.0-23-virtual (ip-10-64-153-96) 06/27/2012 _x86_64_ (1 CPU)
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
xvdap1 0.00 0.32 0.59 1.01 8.11 29.78 47.25 0.07 43.87 23.65 55.72 3.33 0.53
xvdb 0.00 123.70 0.10 136.45 0.34 1040.59 15.25 27.98 204.87 6.85 205.01 1.24 17.00
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
xvdap1 0.00 0.21 0.00 0.62 0.00 3.32 10.67 0.00 1.33 0.00 1.33 0.67 0.04
xvdb 0.00 301.04 0.00 61.89 0.00 1451.71 46.91 7.12 114.97 0.00 114.97 1.27 7.85
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
xvdap1 0.00 0.52 0.00 1.14 0.00 12.84 22.55 0.00 1.09 0.00 1.09 0.73 0.08
xvdb 0.00 274.22 0.00 31.78 0.00 1224.02 77.03 1.16 36.56 0.00 36.56 0.47 1.49
So there doesn't seem to be any substantial disk activity.
MAX_CACHE_SIZE is set to 1000000, MAX_CREATES_
ubuntu@
1398 root 20 0 460m 378m 1968 S 38.4 10.1 40:52.62 carbon-cache.py
15838 root 20 0 8 4 0 R 3.8 0.0 0:00.02 carbon-cache.py
1398 root 20 0 460m 378m 1968 S 58.8 10.1 40:54.39 carbon-cache.py
1398 root 20 0 460m 378m 1968 S 64.7 10.1 40:56.34 carbon-cache.py
1398 root 20 0 460m 378m 1968 S 55.7 10.1 40:58.02 carbon-cache.py
This is running on a ec2.medium instance with 1 CPU and 4GB memory.
How do I increase the rate at which creates happen?
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