[OmniOS-discuss] arcstat ZFS question

[Richard Skelton]

Hi,
I am running OmniOS r151020 on an Intel S2600WTTR with two Intel(R)
Xeon(R) CPU E5-2640 v4 @ 2.40GHz CPU and 256GB of memory.
The zpool scratch is made up of 16 x 600GB 15K rpm SAS drives with a
DDRdrive as log and a 750GB INTEL-SSDPEDMD800G4 NVME card as cache.
When I run du I see a lot of L2misses from arcstat also the L2size seems
a lot bigger than the used size shown by zpool iostat scratch.
Why does du generate writes?
Is this normal?

Cheers
Richard

root at hosta:/scratch# du -sh *
201M    dir01
59G     dir02
136K    dir03
6.7G    dir04
1.4G    dir05
133K    dir06
726K    dir07
6.6G    dir08
268K    dir09
12G     dir10
146K    dir11
137M    dir12
29G     dir13
3.9G    dir14
83M     dir15
244M    dir16
201M    dir17
382K    dir18
242M    dir19
199M    dir20
405K    dir21
root at hosts:/scratch#

07:44:53     0     0     0     0       0       0       0       0  
118G    607G
07:45:03  3.4K  1.0K  2.4K    29    2.4K       0    2.4K       0  
118G    607G
07:45:13   41K   30K   10K    73     10K       0     10K       0  
119G    607G
07:45:23   40K   23K   17K    57     17K       0     17K       0  
119G    607G
    time  read  hits  miss  hit%  l2read  l2hits  l2miss  l2hit%  arcsz 
l2size
07:45:33   44K   21K   23K    48     23K       0     23K       0  
119G    607G
07:45:43   46K   28K   18K    59     18K       0     18K       0  
119G    607G
07:45:53   24K  7.2K   17K    29     17K       0     17K       0  
119G    607G
07:46:03     1     1     0    90       0       0       0       0  
119G    607G
07:46:13     0     0     0   100       0       0       0       0  
119G    607G

17 March 2017 07:46:16 GMT
                               capacity     operations    bandwidth
pool                        alloc   free   read  write   read  write
--------------------------  -----  -----  -----  -----  -----  -----
scratch                      118G  3.07T      0      0      0      0
  mirror                    19.6G   524G      0      0      0      0
    c5t5000CCA018364819d0       -      -      0      0      0      0
    c6t5000CCA018355AF1d0       -      -      0      0      0      0
  mirror                    19.7G   524G      0      0      0      0
    c7t5000CCA018330A55d0       -      -      0      0      0      0
    c8t5000CCA0183561F5d0       -      -      0      0      0      0
  mirror                    19.7G   524G      0      0      0      0
    c9t5000CCA01832FA21d0       -      -      0      0      0      0
    c10t5000CCA018356271d0      -      -      0      0      0      0
  mirror                    19.5G   524G      0      0      0      0
    c11t5000CCA01830A3E1d0      -      -      0      0      0      0
    c12t5000CCA018331455d0      -      -      0      0      0      0
  mirror                    19.5G   524G      0      0      0      0
    c13t5000CCA018356211d0      -      -      0      0      0      0
    c14t5000CCA018339B1Dd0      -      -      0      0      0      0
  mirror                    19.6G   524G      0      0      0      0
    c15t5000CCA01837D171d0      -      -      0      0      0      0
    c16t5000CCA0387184FDd0      -      -      0      0      0      0
logs                            -      -      -      -      -      -
  c21t0d0                    128K  3.84G      0      0      0      0
cache                           -      -      -      -      -      -
  c17t1d0                    109G   636G      0    115      0   294K
--------------------------  -----  -----  -----  -----  -----  -----