stats command

[p-wu57]

Hi , regarding command "stats", I would like to know about the meaning of output.

for example, as below,

__________________________________________________________________________________________________________

/$ stats  --diff --vol test-vol  --interval 5

Will use per-second statistics

Stats from 2014-04-30,14:45:19 to 2038-01-19,12:14:07

       vol       reads            rdKB      writes         wrKB    seqRead%   nsMemHit%   nsSsdHit%           memKB           ssdKB           hddKB       hddSnapKB

test-vol        666           11506           4               9                1                    23                     2                         0                    0                    0                    0

__________________________________________________________________________________________________________

volume name: test-vol.

reads: IOPS of read ?

writes: IOPS of write ?

nsMemHit%: read cache hit rate in memrory?

nsSsdHit%: read cache hit rate in SSD?

total cache hit rate will be nsMemHit%+nsSsdHit%, right?

if anyone can have a comment?

Thanks in advance

Peggy

[rugby0134 · Accepted solution]

I believe your correct.

nsMemhit is the amount of data read back from NVram and/or DIMMs.  This would be data that was written in the last few seconds and then requested for read.

nsSSDHit is the amount of data reads from the SSD pools.  So the total read cache hit ratio is nsMEmhit + nsSSDHit.

From the stats above, i would guess that the data is large sequential blocks.  Large sequential blocks are not moved into SSD cache because the Nimble arrays can read large sequential blocks just as fast from SSD or the SATA pools.

[rugby0134]

Here's good blog on that topic Glick's Gray Matter: Nimble Performance 101 - CLI Style