DELL-ToddM We're waiting a few minutes for people to join before starting
slbrown Hello Todd.
DELL-ToddM Any specific questions / areas you want to cover today?
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DELL-ToddM Welcome Roger and Darren
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Dell-RogerF Afternoon
DELL-ToddM Just giving everybody a few minutes to join up
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DELL-ToddM Let's go ahead and start the chat
DELL-ToddM Today's topic is Virtualizing Sql Server
DELL-ToddM Specifically the work that I have done with Sql Server has been on Vmware Esx Server
DELL-ToddM Most recently (yesterday) I published a whitepaper with a performance characterization of Sql Server 2005 on Esx Server 3.5
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DELL-ScottH hey Marc
Dell-MarcFarley what's up?
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DELL-ToddM There is a home page for the whitepaper on the site at
DELL-ToddM Hey Marc - just getting started
DELL-ToddM In addition to the home page for the whitepaper, there is also a landing page for Sql Server on Vmware at
DELL-ToddM The paper really covers two sets of tests with 64-bit Sql Server 2005 Vms
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DELL-ToddM The first set of tests measures the performance scaling as additional vcpus are added to a single Vm
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DELL-ToddM And how performance scales with multiple Vms
DELL-ToddM And the best part - used lots of graphs with mulitple colors to illustrate the results!
DELL-ToddM The overall finding for scaling within a single Vm was that performance scales about as well as a physical server would scale as you add vcpus or processors
DELL-ToddM In other words - you don't get linear scalablity, but you do a healthy increase in performance
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DELL-ToddM The reason for this test was that in the past, with previous versions of Esx, there was some concern about the performance of multi vcpu Vms
DELL-ToddM In my testing, as reported in the whitepaper, the performance of the 2 vcpu and 4 vcpu Vm was great.
DELL-ScottH which processors did you use in the server ?
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DELL-ToddM The physical server used in the testing was a 2950 with quad-core 3.16 Ghz processors
DELL-ToddM So there were 8 cores in the server, and 32 Gb of Ram
DELL-ToddM Basically a max configuration
DELL-ToddM In the single Vm testing the full resources of the server weren't really stressed - as a single Vm can only be assigned up to 4vcpus (which amounts to 4 cores)
DELL-ToddM So to put the full power of the server to the test I did some multi Vm testing next
DELL-ToddM Using the results from the single Vm test, a baseline of performance was established for the 1vcpu, 2vcpu, and 4vcpu Sql Server Vms
DELL-ToddM I then ran tests with 2,3, and 4 of each of these to see how performance scaled across all the Vms
DELL-ToddM The results showed that Esx was able to evenly distribute server resources across the Sql Server Vms - providing good performance scaling
DELL-ToddM Each Sql Server Vm was able to achieve nearly the same amount of transactions per minute as the baseline - even though multiple Vms were running at the same time
DELL-ToddM Up to a point
DELL-ScottH is it possible to compare these results to running on a physical server ? .. perhaps if one was considering moving from physical to virtual to get a rough guestiumate on perf gains/loses
DELL-ToddM Once the server processors became overcommitted (or over subscribed) performance scaled no further
DELL-ScottH and where did you find bottlenecks in your testing ?
DELL-ToddM The maximum number of transactions across all four Vms was limited to just over 50,000 Orders Per Minute - which was bottlenecked by the processors
DELL-ToddM Each Sql Server Vm had a 100 Gb Dell Dvd Store database - with 20 dedicated datadisks and 2 dedicated log disks
DELL-ToddM So everytime I added a Vm into the testing, it came with it's own disks
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DELL-ToddM A key point about running Sql Server in a Vm-
DELL-ToddM You still have to size the storage correctly
DELL-ToddM just like a physical server
Dell-Darren Todd you may have covered this but what type of workload were you running? Oltp, Olap, Bi, etc.?
DELL-ToddM Oltp - The Dell Dvd Store is a test app that Dave Jaffe and I developed and opensourced
DELL-ToddM It is an online Dvd Store that allows you to logon, browse for discs, and purchase them
DELL-ScottH I'm looking at your charts and the 4VM 2vcpu shows ~55K Opm and the 4VM 4vcpu shows ~50K Opm .... I can understand 4x4 and 16 cores being maxed out ... but did you try scaling beyond that in the 2vcpu tests ? .... maybe a 5th or 6th 2vcpu test ?
DELL-ToddM It includes most standard Db stuff - primary and forgein keys, indexes, full-text indexes, and multi-phase transactional
DELL-ToddM I ran out of disks with the 2vcpu Vms, so could not add more Vms to test
DELL-ScottH ahh, makes sense, maybe Marc can help us out with that
DELL-ToddM I was also out of Ram on the server - 8GB per Vm (actually had to drop back to 7.5 Gb for the 4 Vm tests)
DELL-ScottH do you think it would continue to scale until max cores ?
DELL-ScottH which parts on this Sql test bottleneck first ? .. Ram, disk, Cpu
DELL-ToddM The Dvd Store will usually max out disk first, then Cpu. So you have to make sure that you have enough disks for the processors that you are using
DELL-ToddM During initial phase of testing, perf monitoring showed that 20 data disks was enough to max out 4vcpu Vm
DELL-ToddM I verified this by using 30 disks and getting no additional performance gain
slbrown what type of data source where you connected to?
DELL-ToddM The storage was a Cx3-80 fibre channel array
DELL-ToddM Specific disk layout was 2 10 Disk Raid 1/0 (to make 20 data disks) and a Raid 1 for logs
slbrown you may want to add that information to the test configuration as it provides some insight into what the backend storage was for the test
DELL-ToddM It is in the full version of the whitepaper - the Pdf that is linked at the top
DELL-ToddM The wiki page has the highlights
DELL-ToddM I will add the storage configuration table to the wiki page - thanks for the suggestion
DELL-ToddM Anybody else have any performance with Server stories they would like to tell
DELL-ToddM Sql Server - that is
DELL-ToddM The second half of the paper deals with Vmotion of Sql Server Vms
DELL-ToddM One of the reasons to virtualize Sql Server is to be able to take advantage of Vmotion and the features that it enables
DELL-ToddM So to me, it makes alot of sense to also measure the performance or impact of Vmotion with Sql Server Vms
DELL-ToddM In order to test this, I created a test that would move a Vm using Vmotion back repeatedly over a 90 minute period
DELL-ToddM While under moderate load
DELL-ToddM In order to report the results I looked at a few things
DELL-ToddM First was to make sure that Vmotion did not break Sql Server or cause lost transactions
DELL-ToddM During all the Vmotion tests that I did for the paper, there were no errors in the event log
DELL-ToddM Sql Server continued to process transactions,
DELL-ToddM and no errors were reported from the client side
DELL-ToddM So there were no problems found during testing - which is really important
DELL-ToddM The time for the Vmotion to complete ( from the time the command was issued until the Vm was on the new server) did increase
DELL-ToddM as the "size" of the Vm increased
DELL-ToddM But the increase was not extreme
DELL-ToddM The small 1vcpu Vm moved in 1min 49 sec
DELL-ToddM The Large 4vcpu Vm moved in 3 min 6 sec
DELL-ToddM There was a measurable difference in overall Orders Per Minute, but it was very small
DELL-ToddM The most visible indicator of the Vmotion events was in the Cpu utilization of the Vm itself.
DELL-ToddM There was a very brief spike during each Vmotion
DELL-ToddM This was due to the brief queuing that would occur during the 1 or 2 that the Vm was actually moving from one physical server to another
DELL-ToddM So, the net was that Vmotion works good with Sql Server Vms
DELL-ToddM The funny thing is that this Vmotion test is very similar to the testing that I did in my first whitepaper on Vmware
DELL-ToddM I'm digging up the Url
DELL-ToddM Lots has changed since then, but testing Vmotion is the common element
DELL-ToddM I've been out looking on the web and on blogs for others running Sql Server on Vmware
DELL-ToddM I've found a few blogs and whitepapers from others
DELL-ToddM I'll be posting these to the Sql and Vmware wiki page
DELL-ToddM I've also done some work with a combined Emc, Vmware, Dell team on Sql Server
DELL-ToddM The results of that work should be coming out soon
DELL-ToddM Anybody have any questions?
DELL-ToddM Darren - I saw you typing a few times, but nothing every showed up - Was there something you wanted to comment on?
DELL-ScottH do you have any thoughts on how this might work with iscsi for backend disks ?
Dell-Darren Well I was going to comment on some performance characteristics of Sql Server and how they apply in Vmware because that's one area where I haven't run any tests. You ended up covering most of what I had questions about.
Dell-Darren In terms of running this with iscsi, the scaling should be similar. The one nice thing about fibre channel is you don't have to worry about the switches so much.
Dell-Darren With iscsi you can hit potential bottlenecks at the switch infrastructure level.
DELL-ToddM We have our Equallogic arrays on order - and I want to run some similar tests when they get in
Dell-Darren I'd be very curious to the outcome of those tests. Unfortunately I do not have any servers here equivalent to the ones you used.
DELL-ToddM I would also like to link to the new Dell Inside It blog (with Marc Farley as lead blogger) -
DELL-ToddM This is the first week - and it has had some pretty good posts
DELL-ToddM Well, we have gone over the time by just a few minutes
DELL-ToddM Next week's chat will be hosted by Scott Hanson and the topic will be....
DELL-ScottH Systems Management open discussion -- similar to a radio talk show with open callers ... should be fun !
DELL-ScottH unless we get prank callers :-)
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DELL-ScottH thanks for hosting Todd
Dell-Darren Thanks Todd.
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DELL-ToddM Thanks to everybody for coming
slbrown Thanks for sharing your findings.
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