RMAN vs ZFS Compression

Continuing from my Last blog on ZFS compression, this is the RMAN day.

I wanted to bring about few statistics in performance (time and space) but this time -
RMAN versus ZFS compression.

RMAN does compresses on the fly (cliche is it??)

I did a test of backing up 2 datafiles size 2*30GB using RMAN basic compression on ZFS with no compression enabled and then RMAN no compression with ZFS compression enabled to LZJB.

I have already shown that compressing above lzjb certainly requires you to monitor controller's cpu utilization carefully.

(My Setup is same as last time ZFS - 7330, exadata - quarter rack, with both connected using infiniband network)

Here are few statistics for your for 2 datafiles to get the maths running in the head  -
I will give for the full database next.

Raw DF size	Backup Type	Time Taken	Ratio	Size (raw)	Size (ZFS)	Ratio (Size, appx)
			(Time, appx)
61440 GB -2 Datafiles	Normal	55 secs	1	15GB	4.0GB	1
61440 GB -2 Datafiles	Compressed backupset	5:45 minutes	6	2.2GB	2.2GB	0.5

So now you can start doing the math in your head. Pretty neat isn't it.
Remember the compression was LZJB in the first case.  ZFS compressed it nicely.
Now here are the stats for the full databases, I have rounded out few figures for better calculation, the key idea is that you should get the broader picture..

Database	Backup Type	Time Taken	Ratio	Size (raw)	Size (ZFS)	Ratio (Size, appx)
			(Time, appx)
6.0TB	Normal	2 hours	1	2.8T	1.8T	1.5
6.0TB	Compressed backupset	10 hours	5	1.2T	1.2T	1

Note - Am not really good in formatting, so you see some stuff moving out of the ruler lines, pardon me for that :).