How to read the fields of the vxtrace output
|Article:HOWTO31294|||||Created: 2010-09-09|||||Updated: 2012-07-22|||||Article URL http://www.symantec.com/docs/HOWTO31294|
One of the fields in the vxtrace output is the concurrency value of an IO transaction.
Excerpt from a vxtrace output that shows this field :
600 96003 START write vdev datadev1 dg scsefpsddb1 dev 0,41002 block 3004640 len 16 concurrency 51079 pid 2586
601 96003 START write disk HDS9980V0_2 op 600 block 3004640 len 16
602 96003 START write vdev datadev1 dg scsefpsddb1 dev 0,41002 block 3004656 len 16 concurrency 51080 pid 2586
603 96003 START write disk HDS9980V0_2 op 602 block 3004656 len 16
601 96003 END write disk HDS9980V0_2 op 600 block 3004640 len 16 time 0
600 96003 END write vdev datadev1 dg scsefpsddb1 op 600 block 3004640 len 16 time 0
603 96003 END write disk HDS9980V0_2 op 602 block 3004656 len 16 time 0
602 96003 END write vdev datadev1 dg scsefpsddb1 op 602 block 3004656 len 16 time 0
Concurrency is the number of I/Os pending against a Volume Manager virtual device (vdev) - it is a measure of how many concurrent I/Os were happening against that virtual device at that point in time.
This number increases as additional processes are detected.
The I/O requests passed to Volume Manager are tagged with the system lbolt which is the number of clock ticks since boot. When these requests are completed, the starting lbolt is subtracted from the current lbolt to determine the elapsed time of the request. This elapsed time is reported by vxtrace.
lbolt represents 100ths of a second, so the values reported in time by the vxtrace command are also reported in 100ths of a second.
Is only listed at write ends.
It indicates the end of a block read. For example:
14242 END read vdev BPSA061PRODDumpVol op 14242 block 107598384 len 16 time 0
The number following the "op" indicates the completion of the read I/O 14242 from the volume.
Article URL http://www.symantec.com/docs/HOWTO31294