Can someone remind me why replicate on write tasks might be related to the high disk I/O? My understanding is the replicate on write involves sending the update to other nodes, so it shouldn't involve any disk activity -- disk activity would be during the mutation/write phase.
The write path (not replicate on write) for counters involves a read, so that explains the high disk I/O, but for that I'd expect to see many write requests pending (which we see a bit), but not replicate on writes backing up. What am I missing? Andrew On Wed, Jul 3, 2013 at 1:03 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Wed, Jul 3, 2013 at 9:59 AM, Andrew Bialecki <andrew.biale...@gmail.com > > wrote: > >> 2. I'm assuming in our case the cause is incrementing counters because >> disk reads are part of the write path for counters and are not for >> appending columns to a row. Does that logic make sense? >> > > That's a pretty reasonable assumption if you are not doing any other reads > and you see your disk busy doing non-compaction related reads. :) > > =Rob >
