Hello
I am analyzing disk performance OSR5.0.7 running inside VirtualBox.
GUEST: osr5.0.7; 1GB ram; raw disk
HOST: SLES11SP3, 4GB ram; 1 disc SATA2-7200rpm
But I'm not sure how to do it right (the values returned by sar not match the values of the physical machine)
The attributes analyzed are:
blks/s: if not int or out, but converted to MB/s should be: blks/s * 512 /1024 /1024
bread/s: I understand you are the KB/s read from the disk that are not in the cache, with this iconclude that it is the ratio of the hard disk read.
bwrit/s: I understand you are the KB/s written when a flush is done, so i conclude that it is the ratio of the hard disk write.
To measure the performance I use the command:
time sh -c "dd if=/dev/zero of=pruebaHD-4254.dd count=131072 bs=8k ibs=8k conv=sync && sync"
Generating a file the size of the ram and then calculate the MB/s based on the value returned by time (repeat the process with different sizes of bs, then iterate 3 times)
With that understanding, when I see I have the values:
blks/s : max: 86.98 MB/s avg: 16.77 MB/s
bread/s : max: 3.10 MB/s avg: 241.66 KB/s
bwrit/s : max: 86.98 MB/s avg: 16.12 MB/s
According to "time dd" achievement Min: 20MB/s Max: 43MB/s Avg: 30MB/s.
According zabbix host 36MB/s
Since the values are not similar, they conclude that something is wrong in my analysis.
I am misunderstanding sar values?
It is a misconception and I'm looking at it all wrong?
How I can know the ratio I / O disk presicion in OSR5.0.7?
thanks