[OmniOS-discuss] questions

Thu Sep 14 14:10:09 UTC 2017

On September 14, 2017 2:26:13 PM GMT+02:00, Dirk Willems <dirk.willems at exitas.be> wrote:
>Hello,
>
>
>I'm trying to understand something let me explain.
>
>
>Oracle always told to me that if you create a etherstub switch it has 
>infiniband speed 40GB/s.
>
>But I have a customer running on Solaris (Yeah I know but let me 
>explain) who is copy from 1 NGZ to another NGZ on the same GZ over Lan 
>(I know told him to to use etherstub).
>
>The copy witch is performed for a Oracle database with sql command, the
>
>DBA witch have 5 streams say it's waiting on the disk, the disk are 50
>- 
>60 % busy the speed is 30 mb/s.
>
>
>So I did some test just to see and understand if it's the database or 
>the system, but with doing my tests I get very confused ???
>
>
>On another Solaris at my work copy over etherstub switch => copy speed 
>is 185MB/s expected much more of infiniband speed ???
>
>
>root at test1:/export/home/Admin# scp test10G 
>Admin at 192.168.1.2:/export/home/Admin/
>Password:
>test10G              100% 
>|****************************************************************|
>10240 
>MB    00:59
>
>
>root at test2:~# dlstat -i 2
>
>  LINK    IPKTS   RBYTES    OPKTS   OBYTES
>            net1   25.76K 185.14M 10.08K    2.62M
>            net1   27.04K  187.16M   11.23K    3.22M
>            net1   26.97K  186.37M   11.24K    3.23M
>            net1   26.63K  187.67M   10.82K    2.99M
>            net1   27.94K  186.65M   12.17K    3.75M
>            net1   27.45K  187.46M   11.70K    3.47M
>            net1   26.01K  181.95M   10.63K    2.99M
>            net1   27.95K  188.19M   12.14K    3.69M
>            net1   27.91K  188.36M   12.08K    3.64M
>
>The disks are all separate luns with all separated pools => disk are 20
>
>- 30% busy
>
>
>On my OmniOSce at my lab over etherstub
>
>
>root at GNUHealth:~# scp test10G witte at 192.168.20.3:/export/home/witte/
>Password:
>test10G 76% 7853MB 116.4MB/s
>
>
>=> copy is 116.4 MB/s => expected much more from infiniband speed is 
>just the same as Lan ???
>
>
>Is not that my disk can not follow 17% busy there sleeping ...
>
>    extended device statistics
>     r/s    w/s   Mr/s   Mw/s wait actv wsvc_t asvc_t  %w  %b device
>     0,0  248,4    0,0    2,1  0,0  1,3    0,0    5,3   0 102 c1
>    0,0   37,5    0,0    0,7  0,0  0,2    0,0    4,7   0  17 c1t0d0 => 
>rpool
>    0,0   38,5    0,0    0,7  0,0  0,2    0,0    4,9   0  17 c1t1d0 => 
>rpool
>    0,0   40,5    0,0    0,1  0,0  0,2    0,0    5,6   0  17 c1t2d0 => 
>data pool
>    0,0   43,5    0,0    0,2  0,0  0,2    0,0    5,4   0  17 c1t3d0 => 
>data pool
>    0,0   44,5    0,0    0,2  0,0  0,2    0,0    5,5   0  18 c1t4d0 => 
>data pool
>    0,0   44,0    0,0    0,2  0,0  0,2    0,0    5,4   0  17 c1t5d0 => 
>data pool
>     0,0   76,0    0,0    1,5  7,4  0,4   97,2    4,9  14  18 rpool
>     0,0  172,4    0,0    0,6  2,0  0,9   11,4    5,5  12  20 DATA
>
>
>
>root at NGINX:/root# dlstat show-link NGINX1 -i 2
>
>  LINK  TYPE      ID  INDEX     PKTS    BYTES
>          NGINX1    rx   bcast     --        0        0
>          NGINX1    rx      sw     --        0        0
>          NGINX1    tx   bcast     --        0        0
>          NGINX1    tx      sw     --    9.26K  692.00K
>          NGINX1    rx   local     --   26.00K 216.32M
>          NGINX1    rx   bcast     --        0        0
>          NGINX1    rx      sw     --        0        0
>          NGINX1    tx   bcast     --        0        0
>          NGINX1    tx      sw     --    7.01K  531.38K
>          NGINX1    rx   local     --   30.65K 253.73M
>          NGINX1    rx   bcast     --        0        0
>          NGINX1    rx      sw     --        0        0
>          NGINX1    tx   bcast     --        0        0
>          NGINX1    tx      sw     --    8.95K  669.32K
>          NGINX1    rx   local     --   29.10K 241.15M
>
>
>On the other NGZ I receive 250MB/s ????
>
>
>- So my question is how comes that the speed is equal to Lan 100MB/s on
>
>OmniOSce but i receive 250MB/s ?
>
>- Why is etherstub so slow if infiniband speed is 40GB/s ???
>
>
>I'm very confused right now ...
>
>
>And want to know for sure how to understand and see this in the right 
>way, because this customer will be the first customer from my who gonna
>
>switch complety over to OmniOSce on production and because this
>customer 
>is one or the biggest company's in Belgium I really don't want to mess 
>up !!!
>
>
>So any help and clarification will be highly appreciate !!!
>
>
>Thank you very much.
>
>
>Kind Regards,
>
>
>Dirk

I am not sure where the infiniband claim comes from, but copying data disk to disk, you involve the slow layers like disk, skewed by faster layers like cache of already-read data and delayed writes :)

If you have a wide pipe that you may fill, it doesn't mean you do have the means to fill it with a few disks.

To estimate the speeds, try pure UDP streams from process to process (no disk), large-packet floodping, etc.

I believe etherstub is not constrained artificially, and defaults to jumbo frames. Going to LAN and back can in fact use external hardware (IIRC there may be a system option to disable that, not sure) and so is constrained by that.

Jim
--
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