"dd" Read From ACFS Filesystem Is Slow (Doc ID 2122848.1)

Last updated on OCTOBER 31, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 and later
Information in this document applies to any platform.

Symptoms

We use ACFS filesystem to store Goldengate trail files on OGG source and target side.

"dd" read test result
ACFS read speed OGG volume disk volume disk speed
OGG source 71MB/s /dev/asm/ggatevol-40 7MB/s                      <<----------- 71 MB/s
OGG target 4.5MB/s /dev/asm/ggate-50 15MB/s                         <<-----------4.5 MB/s

Need to identify the root cause why "dd" read on OGG target side is slow.
$ time dd if=gg001649 of=/dev/null ibs=30000 obs=4096 count=17067 ( read 500MB trail file)
real 1m50.32s 500MB/(1m50seconds) = 4.5MB/second                   <<--------- 4.5 MB/s
user 0m1.81s
sys 0m2.49s

Cause

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