Log File Syncs

I was wondering if someone could maybe help me out with an unusual observation I have on a couple of test systems. I have a user reporting that they are seeing differences in performance between the database on a VM (which is running 'fast') and a database on a physical (which is running slow)

They are performing a load from MongoDB via a PHP app into the oracle database. In both tests the same source database is being used.

I've done a quick overview on each of the systems and the only thing that is jumping out at me is that on the faster DB the log file sync time is much lower on the faster one. (the output was gather using oratop) Both DB's are 12.1.0.2. The faster one is on CentOS 6.6 and the Slower one on Redhat 5.11.

Slow DB

EVENT     (Real-Time)       AVG: TOT WAITS  TIME(s)  AVG_MS PCT  WAIT_CLASS
log file parallel write           20008284    23783     1.2 100  System I/O
log file sync                         1730        9     5.2   0  Commit
DB CPU                                            0           0


Fast DB
EVENT     (Real-Time)       AVG: TOT WAITS  TIME(s)  AVG_MS PCT  WAIT_CLASS
log file parallel write           20389439    28216     1.4 100  System I/O
log file sync                       179674       74     0.4   0  Commit
SQL*Net message to client                7        0     0.0   0  Network
DB CPU                                            0           0

I'm also a bit confused as to how the log file sync time can be shorter than the log file write time.

Any assistance or advice would be appreciated.

Regards,

Christopher Osborne

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