Symantec support is very helpful on this matter. He confirmed that concurrency is the number of I/O operation on the volume.
For example: 4275 START write vdev homevol01 block 5771246912 len 128 concurrency 31 pid 6134 ³Concurrency 31² means there are 31 write operations on volume homevol01. Cheers, carl On 9/20/10 11:19 PM, "William Havey" <bbha...@gmail.com> wrote: > I've not been able to find an understandable description of "concurrency". > But, I have an example vxtrace output from a simple stripe volume with a bad > stripe size: > vxtrace -g S1dg1 -f /tmp/appiolab1.out -o dev,disk | pg > > 1 START write vdev test block 35840 len 64 concurrency 1 pid 10931 > > 2 START write disk c1t3d0s2 op 1 block 20224 len 16 > > 3 START write disk c1t3d1s2 op 1 block 20224 len 16 > > 4 START write disk c1t3d0s2 op 1 block 20240 len 16 > > 5 START write disk c1t3d1s2 op 1 block 20240 len 16 > > 2 END write disk c1t3d0s2 op 1 block 20224 len 16 time 0 > > 3 END write disk c1t3d1s2 op 1 block 20224 len 16 time 0 > > 4 END write disk c1t3d0s2 op 1 block 20240 len 16 time 1 > > 5 END write disk c1t3d1s2 op 1 block 20240 len 16 time 1 > > 1 END write vdev test op 1 block 35840 len 64 time 1 > > All the "op 1" statements define a complete I/O, which includes 4 separate > I/Os but the concurrency is 1. By your statement the concurrency should be 4. > > I do have this statement I found somewhere: Concurrency means "the number of > threads monitoring the i/o". But like I say, that statement is meaningless to > me. > > Sorry I can be of only a negative sort of help on this. > > On Mon, Sep 20, 2010 at 8:05 PM, Carl Ma <zhu_ju...@yahoo.ca> wrote: >> Thanks, this is important. My understanding of concurrency means this I/O >> operation was split into 31 sub-tasks and are running at the same time? >> >> >> On 9/20/10 10:43 PM, "William Havey" <bbha...@gmail.com> wrote: >> >>> "op" is short for "operation". Each line in the output of vxtrace is >>> prefixed with a number. This "op number" tells you which other lines forms a >>> complete trace of an I/O. Examine the output of vxtrace for all lines >>> containing "4275" and all these lines represent one I/O. >>> >>> On Mon, Sep 20, 2010 at 6:20 PM, Carl E. Ma <zhu_ju...@yahoo.ca> wrote: >>>> Hi, >>>> >>>> We are using volume manager 5.0 on solaris 9. I have difficulty to >>>> interpret vxtrace output. What does "op" and "concurrency" stand for? >>>> >>>> ==example of output line=== >>>> 4275 START write vdev homevol01 block 5771246912 len 128 concurrency 31 pid >>>> 6134 >>>> 4254 END write vdev homevol01 op 4254 block 208575678 len 16 time 0 >>>> ==end of example=== >>>> >>>> Doug has a script using field $9 and $11 to determine whether this is a >>>> random or sequential operation. Is it still valid in latest vxvm? >>>> >>>> Thanks in advance, >>>> >>>> carl >>>> >>>> >>>> _______________________________________________ >>>> Veritas-vx maillist - veritas...@mailman.eng.auburn.edu >>>> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx >>>> >>> >>> >>> _______________________________________________ >>> Veritas-vx maillist - veritas...@mailman.eng.auburn.edu >>> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-vx >> > >
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