Its a long shot but do you have stream_throughput_outbound_megabits_per_sec or
inter_dc_stream_throughput_outbound_megabits_per_sec set to a low value?
You're right in that 3.0 streaming uses 1 thread for incoming and outgoing
connection each per peer. It not only reads the bytes off of the channel but
also deserializes the partitions on that same thread. If you see high CPU use
by STREAM-IN thread then your streaming is CPU bound. In this situation a
powerful CPU will definitely help. Dropping internode compression and
encryption will also help. Are your SSTables compressed?
Dinesh
On Friday, September 14, 2018, 4:15:28 AM PDT, Vitali Dyachuk
<vdjat...@gmail.com> wrote:
None of these throttling are helpful for streaming if you have even a 150-200
Mbit/s bandwidth which is affordable in any cloud. Tweaking network tcp memory,
window size etc does not help, the bottleneck is not the network.
These are my findings on how streaming is limited in C* 3.0.*
1) Streaming of the particular range which needs to be steamed to the new node
is limited with one 1 thread and no tweaking of cpu affinity etc helps,
probably the powerfull computing VM will help
2) Disabling compression internode_compression and disabling compression per
table in our case helps a bit
3) When streaming has been dropped there is no resume available for the
streaming range so it will start from the beginning
One of the options could be to create snapshots of sstables on the source node
and just copy all sstable snapshots to new node and then run repair, data is
~5TB, RF3 ?
How is it possible at all to stream data fast to a new node/nodes ?
Vitali.
On Wed, Sep 12, 2018 at 5:02 PM Surbhi Gupta <surbhi.gupt...@gmail.com> wrote:
Increase 3 throughput Compaction throughput Stream throughput Interdcstream
throughput (if rebuilding from another DC)
Make all of the above to 0 and see if there is any improvement and later set
the value if u can’t leave these values to 0.
On Wed, Sep 12, 2018 at 5:42 AM Vitali Dyachuk <vdjat...@gmail.com> wrote:
Hi,
I'm currently streaming data with nodetool rebuild on 2 nodes, each node is
streaming from different location. The problem is that it takes ~7 days to
stream 4Tb of data to 1 node, the speed on each side is ~150Mbit/s so it
should take around
~2,5 days . Although there are resources on the destnodes and in the source
regions.
I've increased stream throughput, but its only affects outbound connections.
Tested with iperf the bandwidth is 600Mibt/s from both sides. Last week i've
changed the CS from ST to LC because of huge sstables and compaction of them is
still ongoing.
How does rebuild command works ? Does it calculate the range then request the
needed sstables from that node and start streaming ? How is it possible to
speed up the streaming ?
Vitali.
