I was running hawq check on a system, and I hit the following error:
20160909:16:34:48:339941 gpcheck:hdw1:gpadmin-[ERROR]:-host(hdw1): on
device (sdd) IO scheduler 'cfq' does not match expected value 'deadline'
20160909:16:34:48:339941 gpcheck:hdw1-[ERROR]:-host(hdw1): on device (sde)
IO scheduler 'cfq' does not match expected value 'deadline'
I did a bit of research, and generally I see hadoop hardware guides
recommend cfq as the I/O scheduler, rather than deadline.
- Page 18
http://www.datanubes.com/mediac/HadoopTuningDHT.pdf - Page 9
Have we done any actual benchmarking for HAWQ I/O schedulers? Did we
account for different use cases? Is deadline actually recommended for
systems that run HAWQ, or is this recommendation just a holdover from the
port from Greenplum?