Thanks Richard, Happy New Year.
On 13-01-03 09:45 AM, Richard Elling wrote:
On Jan 2, 2013, at 8:45 PM, Geoff Nordli <geo...@gnaa.net
<mailto:geo...@gnaa.net>> wrote:
I am looking at the performance numbers for the Oracle VDI admin guide.
http://docs.oracle.com/html/E26214_02/performance-storage.html
From my calculations for 200 desktops running Windows 7 knowledge
user (15 iops) with a 30-70 read/write split it comes to 5100 iops.
Using 7200 rpm disks the requirement will be 68 disks.
This doesn't seem right, because if you are using clones with
caching, you should be able to easily satisfy your reads from ARC and
L2ARC. As well, Oracle VDI by default caches writes; therefore the
writes will be coalesced and there will be no ZIL activity.
All of these IOPS <--> VDI users guidelines are wrong. The problem is
that the variability of
response time is too great for a HDD. The only hope we have of getting
the back-of-the-napkin
calculations to work is to reduce the variability by using a device
that is more consistent in its
response (eg SSDs).
For sure there is going to be a lot of variability, but it seems we
aren't even close.
Have you seen any back-of-the-napkin calculations which take into
consideration SSDs for cache usage?
Anyone have other guidelines on what they are seeing for iops with vdi?
The successful VDI implementations I've seen have relatively small
space requirements for
the performance-critical work. So there are a bunch of companies
offering SSD-based arrays
for that market. If you're stuck with HDDs, then effective use of
snapshots+clones with a few
GB of RAM and slog can support quite a few desktops.
-- richard
Yes, I would like to stick with HDDs.
I am just not quite sure what quite a few desktops mean.
I thought for sure there would be lots of people around that have done
small deployments using a standard ZFS deployment.
thanks,
Geoff
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