Much of that depends on the quality of the SSD. Top end SSD improves write
speed more than it improves read speed.
On Wed, Dec 16, 2015 at 9:21 AM, Kellyn Pot'Vin-Gorman <dbakevlar@xxxxxxxxx>
wrote:
I did extensive research to decide what should utilize SSD and found that
it didn't hurt to put redo on SSD, but it didn't offer much benefit and
you simply weren't investigating the real cause of the waits.
I would choose to allocate the SSD to often used indexes or tables than to
waste it on redo. Take the time to research the issue, as writes on SSD
aren't as beneficial as reads and as we all know, redo is write intensive
and the common wait issue.
Kellyn Pot'Vin-Gorman
Consulting Member of Technical Staff, Oracle
On Dec 16, 2015 7:59 AM, "Andrew Kerber" <andrew.kerber@xxxxxxxxx> wrote:
Everything I have read has definitely recommended putting the redo logs
on SSD. I even wrote an article on the subject several years ago.
On Wed, Dec 16, 2015 at 8:54 AM, Storey, Robert (DCSO) <
RStorey@xxxxxxxxxxxxxxxxxx> wrote:
Morning,
I’ve been reading multiple docs on SSD/HDD and the benefits within an
oracle database.
If I am reading this write, for an OLTP system, the SSD/FLASH will
provide excellent random read/write abilities.
But folks seem contradicted on using the SSD for the Redo logs. Some
say its best practice, others say it does not buy you anything.
I have a 24/7 OLTP application that generates a modest amount of redo.
My overall DB is about 95 gigs, I generate about 600megs of redo in a day
(10meg files, switching every 30 or so). My system is getting to end of
life, and I see more log_file_sync waits, and buffer busy waits. I suspect
my I/O subsystems are getting worked hard. My top waits appear to be
sequent file reads and scattered reads, log file sync, and buffer busy.
What’s the general verdict on using SSD for the data files? Best idea
for redos? My thoughts there are separating them to different drives, ie,
two separate single disks, with a group member on each disk.
Thoughts?
Thanks
--
Andrew W. Kerber
'If at first you dont succeed, dont take up skydiving.'
