On 28/05/13 01:41, Jared Morrow wrote:
Toby,
If you write with multiple clients does it still stick to 9mb/s or
does it increase? What is the network link between your client and
the Riak CS cluster? On our internal CS cluster we were seeing
around 2gb/s read+write at the network level so I know CS can take
the speeds, so my gut thinks you single client might have a slow
link. That is just a guess.
The network links are all Ethernet, and appear to be functioning OK.
iperf reports:
bandwidth from client to loadbalancer: 2.20 gbit/sec
bandwidth from loadbalancer to a riak node: 941 mbit/sec
bandwidth from one riak node to another node: 942 mbit/s
I've tested going direct from a client to a riak node rather than via
the loadbalancer, but it doesn't seem to make any difference.
Having tested a bit further now, I'd guess that the problem lies with
Riak rather than Riak CS.
I've noticed that if I try to push files directly into Riak, they go
fairly slowly too - around 10-20mbyte/sec.
I've tried 3, 10 and 50 MB files, against bitcask, leveldb and even
memory backends, and in all cases I get fairly consistent transfer rates
in that range. (just using curl for testing here)
I've tried reducing n_val to 1, there was a small but not significant
improvement.
I'm a bit stumped.. However I do note that the log files seem to have a
lot of "monitor busy_dist_port" messages in them.. I'm wondering if that
might be related somehow?
T
On May 27, 2013, at 1:38 AM, Toby Corkindale
<toby.corkind...@strategicdata.com.au> wrote:
Hi, I seem to be getting significantly slower performance out of
Riak CS than I expect to see, and I wondered if I could get some
advice about where I might be going wrong.
I have a cluster of six nodes, with fairly good sequential-write
disk performance, for eg: # dd if=/dev/zero of=test bs=1M count=500
conv=fsync 524288000 bytes (524 MB) copied, 1.27205 s, 412 MB/s
The riak partition is formatted as ext4, with data=writeback and
barriers disabled.
So given n_val=3, and six nodes with ~400MB/s transfer rates, you'd
expect to see some pretty fast transfers, right?
However the actual performance I'm getting is reliably a mere 9MB/s
for a single client writing to the cluster. (On a 500M transfer)
Is this kind of performance normal for this hardware? If not, could
you give me some pointers about what to check?
Thanks, Toby
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