vioperf skip read

pvannuff

i would like to know the exact meaning of vioperf. how is it calculated and what value can be considered good

LenoyJ

Focus on 'counter value/core' for READ and WRITE.
 
As per this:

Vertica requires a minimum read/write speed of 40 MB/s per physical core of the CPU. However, for best performance, you should have 60–80 MB/s per physical core.

pvannuff

thanks lenoy, but my questions was not correct. Sorry for that. My title was OK but my question was not.
I would like to know the exact meaning of vioperf "SKIP READ". how is skip read calculated and what values can be considered good.

LenoyJ

SKIP READ tests reading non-contiguous data blocks. The docs do make a mention that -

When evaluating performance for minimum and recommended I/O, include the Write and Read values in your evaluation. ReWrite and SkipRead values are not relevant to determining minimum and recommended I/O.

dgrumann

Note vioperf itself says "The minimum required I/O is 20 MB/s read and write per physical processor core on each node, in full duplex i.e. reading and writing at this rate simultaneously, concurrently on all nodes of the cluster. The recommended I/O is 40 MB/s per physical core on each node. " therefore that minimum contradicts the article at https://www.vertica.com/kb/Recommendations-for-Sizing-Vertica-Nodes-and-Clusters/Content/Hardware/Recommendations-for-Sizing-Vertica-Nodes-and-Clusters.htm which says the minimum is 40 MB/s per physical core. Also note that defining what a physical core is in VMware or in the cloud is problematic/impossible.