Re: sysstat and statit

bipul34_gogoi · ‎2011-03-06

Hi all ,

I am trying to find out some relation ( formula !!) . First , for sysstat ...

CPU   NFS CIFS HTTP   Total    Net kB/s   Disk kB/s     Tape kB/s Cache Cache CP   CP Disk    FCP iSCSI   FCP kB/s
                                                    in   out   read write read write   age   hit time ty util                 in   out
32%   430     0     0          430 1923   128    348    972     0     0    32 100% 100% Bv 75%      0     0     0     0
20%   386     0     0          386 1725   116    256    612     0     0    32 100% 100% Bv 73%      0     0     0     0

Whats the relation between TOTAL IOPS and Disk KB/s (Read+write) , Above output is from a load testing with 4KB IO.. (1923+128/430= 4.76)

Secondly , How those relations can be related to invidual disk IOPS

Statit o/p

disk             ut% xfers ureads--chain-usecs writes--chain-usecs cpreads-chain-usecs greads--chain-usecs gwrites-chain-usecs
/aggr4/plex0/rg0:
v5.26             15   6.37    0.09   1.00 365417   6.19   2.03 13595   0.09   4.35 5600   0.00   ....     .   0.00   ....     .
v5.27             16   6.57    0.09   1.00 450435   6.39   2.03 13724   0.09   3.68 6914   0.00   ....     .   0.00   ....     .
v5.28             19   8.10    1.21   1.00 52718   4.87   1.69 20546   2.03   2.65 8867   0.00   ....     .   0.00   ....     .
v5.29             14   5.76    1.18   1.00 49934   2.28   2.50 10604   2.31   2.21 12602   0.00   ....     .   0.00   ....     .
v5.32             14   5.76    1.18   1.00 51887   2.28   2.50 10646   2.31   2.22 12357   0.00   ....     .   0.00   ....     .

Note : v5.26 and v5.27 are parity disk .

From documeantation i can see that Xfers is "total number of disk ops" . Whats the relation (formula) between Xfers from statit o/p and Total IOPS from sysstat command ..

Thanks in advanced

BrendonHiggins · ‎2011-03-06

The statit is the individual disks so you need to add up (ignore parity disks) all the results from each of the raid groups to see what is going on. The sysstat is a total for all the IO and if you have just one aggregate life is simple. If you have multiple I think it shows the information for the busiest aggregate and sum total in other areas. Do not forget to take note of chaining as sequential data can have multiple reads/writes during a single IO event. The total is number of read or writes, multiplied by the chain, multiplied by 4k (block size).

How this helps but it has been a long day and I think I should leave others better able to explain.

Bren

bipul34_gogoi · ‎2011-03-06

Here we have only 1 aggr ..

Do you mean that ..

Total IOPS from sysstat output = sum of XFR from statit o/p of the data disks ??????

Regarding the chain .. whats exactly the value you are refering from the statit o/p .. I can see many chain values . like (ureads--chain-usecs, writes--chain-usecs .......)

Thanks for responding ....

BrendonHiggins · ‎2011-03-07

If you have a look at the slides it tells you what you need to know. http://communities.netapp.com/people/BrendonHiggins/blog/2009/10/21/sept-nug-meeting

This is also a very good link

http://communities.netapp.com/docs/DOC-1051#cf

Hope it helps

Bren

Cloud · ‎2015-05-18

can we get this out via report using Operation manager?