DataStax Academy FAQ

DataStax Academy migrated to a new learning management system (LMS) in July 2020. We are also moving to a new Cassandra Certification process so there are changes to exam bookings, voucher system and issuing of certificates.

Check out the Academy FAQ pages for answers to your questions:


question

kimseng avatar image
kimseng asked ·

What is meant by "mean I/O times" in DS210?

I have some question on this. This is under Exercise 01.04, Step 1

In the ds210-node2 window, observe the output from the previous cassandrastress run. Make note of the mean I/O times.

What do you mean by mean I/O times?

Do you refer to the latency mean on the results of the stress test?

Results:   
op rate                   : 46751 [WRITE:46751]   
partition rate            : 46751 [WRITE:46751]   
row rate                  : 46751 [WRITE:46751]   
latency mean              : 4.3 [WRITE:4.3]   
latency median            : 1.3 [WRITE:1.3]   
latency 95th percentile   : 7.2 [WRITE:7.2]   
latency 99th percentile   : 60.5 [WRITE:60.5]   
latency 99.9th percentile : 223.2 [WRITE:223.2]   
latency max               : 503.1 [WRITE:503.1]   
Total partitions          : 1000000 [WRITE:1000000]   
Total errors              : 0 [WRITE:0]   
total gc count            : 18   total gc mb               : 10742   
total gc time (s)         : 1   avg gc time(ms)           : 73   
stdev gc time(ms)         : 16   Total operation time      : 00:00:21
ds210
10 |1000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.

1 Answer

Erick Ramirez avatar image
Erick Ramirez answered ·

Yes, you are correct. Cheers!

Share
10 |1000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.