Dell EqualLogic iSCSI storage is designed to easily scale as the need for additional capacity and performance grows. This chat will focus on scalability of Dell EqualLogic iSCSI stoage, how it is accomplished, and why it works so well. Leading the chat will be iSCSI experts from Dell and Dell EqualLogic.


Chat Transcript

DELL-ToddM Welcome mgroft
DELL-ScottH hello !
DELL-ToddM We are waiting for others to join for today's iscsi chat
DELL-ToddM We usually have late arrivers and for the first 5 or 10 minutes
DELL-ToddM Today's topic is Scaling Equallogic iscsi storage - although we can stray into other iscsi topics if needed
DELL-ToddM Or other topics entirely if we run out of iscsi stuff to talk about
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DELL-ToddM mgroft - Do you have anything that you want to talk about today?
DELL-ScottH I can talk about Flexaddress and totally take us off topic :-)
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DELL-ToddM Hey slbrown - How goes it?
DELL-ScottH great you scared him away !
slbrown it goes well.
DELL-ToddM I guess that I scared mgroft!
DELL-ScottH you should get a medal for most consistent attendance !
DELL-ScottH what's your id on the site ?
DELL-ToddM Oh well - just trying to be friendly
DELL-ToddM slbrown - Are you a Dell employee?
DELL-ScottH no slbrown on the site .. .ohh well no medal for you !
slbrown yes
DELL-ToddM What group are you in / where are you located?
DELL-ToddM I am in Rr5
slbrown so am i
DELL-ToddM What floor?
slbrown 1st
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DELL-ToddM Hey - It's the iscsi experts!
DELL-TravisV Hello
Dell-Marc what me worry?
DELL-ToddM How it going?
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Dell-Marc good, and you?
DELL-ToddM Welcome f5team
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DELL-ToddM Things are good - I enjoyed your coverage of the Diane Greene thing
DELL-ToddM Welcome Jeff
Dell-Marc That was the event of the month, right there.
DELL-TravisV That was a beautful picture, Marc.
Dell-Marc I can guess which one you are referring.
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f5team Thanks, I can't find the sound button though :) J/k
DELL-TravisV Yup
DELL-ToddM I did my own post as well on the Vmware Ceo change as well - http://www.delltechcenter.com/page/07-10-2008+guaranteed+better+vmworld+keynote+comments
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DELL-ToddM Opps - forgot to tell Travis about the clicking on links thing
DELL-ScottH hey Darin, how goes it ?
DELL-ScottH got one !
DELL-ToddM You should right click on links to avoid leaving the chat
Dell-Marc I saw it Todd, I thought it was funny - because it was true
f5team Good thanks! Looking 4 sum eye scuzzie info
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DELL-ScottH lol
DELL-ScottH looks like you need the 101 session !
f5team yes, I'm way behind, Master Yoda
DELL-ToddM At this point I believe that everybody on the chat is Dell - so we are kind of waiting for customers to join
DELL-ScottH that would be Marc, I am only at Star Wars episode iii luke ability
Dell-Marc Yeah, well I always like it when Travis is around!
DELL-ScottH yeah you guys always have "engaging" conversations
Dell-Marc no no no, he can correct my wayward wanderings!
DELL-ToddM We have a few more Equallogic shelves on order as of last week
DELL-TravisV Huh. I'm still recovering from looking at Marc's pictures...
Dell-Marc Good!
DELL-ToddM Looking forward to doing some Hyper-v Vm testing with Equallogic as the storage
DELL-TravisV : ::smoke
DELL-TravisV Good!
DELL-TravisV Hyper-v
DELL-ToddM As a followup to the chat from a couple of weeks ago - I posted a page this morning on Md3000i performance monitoring
Dell-Marc T-man, where did you get "smoking dude"? He's not in my pallette.
DELL-ToddM It turns out that it is possible to use the command line - smcli.exe - to gather array level perf stats
DELL-ToddM Here is a blog entry with a link to the page - http://www.delltechcenter.com/page/07-15-2008+array+level+md3000i+performance+monitoring+comments
DELL-TravisV : smoke
DELL-ScottH quick, customers needed !
DELL-TravisV Okay.
DELL-TravisV What's the rule? 10 minutes?
DELL-TravisV 20 minutes?
DELL-ToddM Marc - What's the latest in equallogic land?
Dell-Marc We've got some very cool things coming up - that we can't discuss here, other than that, we are rolling along very nicely
Dell-Marc As more people see what the product can do, we have growing success.
DELL-ToddM I really like the Equallogic arrays that we have - and it was easy to add the second one to the first
DELL-ToddM But that is all that we have currently
DELL-ToddM Until the three additional shelves show up in about a week
Dell-Marc So that's a great cue,
Dell-Marc What are you using your arrays for now?
DELL-ToddM I'm using them for Vms - some Esx and some Hyper-v
DELL-ToddM The Vms are running Sql Server and Lamp stack (dell Dvd Store workloads)
Dell-Marc One of the things you ought to try when you get the new arrays is to add a new array to the group and then remove one of the exisitng ones.
Dell-Marc That shows how you can re-purpose older equipment
DELL-ToddM Currently one of our shelves has 7200 Rpm disks and the other has 15K Rpm disks
DELL-ToddM All of the new shelves will have 15K disks
Dell-Marc Yeah, so you could put in a new 15K array. and then evacuate the 7200 array and remove it from the group. It gives you a great perspective on how scalability works
Dell-Marc You can scale capacity or performance or both at the same time
DELL-ToddM And when I evacuate the older slower shelf - it will migrate the data to the new shelf?
Dell-Marc Yes, it actually spreads the data across the other arrays in the group. It restructures all the data over the remaining arrays in the group
DELL-ToddM Automagically? Are there any options that you have to specify?
Dell-Marc You have to add usable capacity to an exisitng volume first
Dell-Marc but then when you evacuate, the arrays work together to figure out what data goes where
DELL-ToddM Would it make sense to record a demo of this when I do it? Or does something already exist?
Dell-Marc There is no copy command, the system knows what data is most heavily accessed and spreads it out over the resources that are available
DELL-ToddM We could post on delltechcenter.com wih our other great demos - http://www.delltechcenter.com/page/demonstrations
Dell-Marc Its a great idea to record a demo - I don't think one exists
Dell-Marc you need to do it in time lapse though, because it takes several hours to do
DELL-ToddM That's cool - I will just leave the stuff that you actually click on in real time, and the rest will be time lapse
Dell-Marc It uses the systems algorithms for load balancing - which are designed to not over-react to sudden, temporary workloads
DELL-ToddM Scott is the demo recording master - so I may have to get his assitance
Dell-Marc One of the keys to load balancing is to take plenty of time to prevent thrashing
DELL-ToddM It will be interesting to see how it reacts to my testing workloads then - becuase they might seem like sudden temp type of workload
Dell-Marc Its a cool opportunity for channel partners to help their customers too
DELL-ToddM Is there a rule of thumb for how long you need to run a test?
Dell-Marc Not that I know of
Dell-Marc The whole idea of upgrading on the fly is such a foreign concept, most people don't believe it can be done that way, but when they see it, they are amazed
Dell-Marc The key to it is the distributed volume manager in the Ps5000 arrays
DELL-ToddM The software on the arrays is clearly the advantage of the Ps5000 arrays
Dell-Marc Todd, back to your question about "how long to run a test" There is some dependence on the amount of data stored in the system, but I don't have any "rules of thumb" for you.
Dell-Marc Another thing that really makes a difference is the way the Ps5000s use the iscsi redirect function
DELL-ToddM I'll figure it out, I'll be sure to run some warm-up tests that are long enough to ensure that the arrays have done what they want to do in terms of optimizing things
Dell-Marc Sounds good
DELL-ToddM In terms of scaling out with Equallogic arrays - Is there a limit or best practice for max number of shelves?
Dell-Marc That's a really good question. Some of our customers top out at 4 -5 arrays in a group. It can be higher, but I think it makes sense to limit the size of the groups.
Dell-Marc There aren't any defined best practices for this yet
Dell-Marc Btw, its a small thing, but we try not to call them shelves because they are complete systems, not just drives and connectors. Every system is complete with all the stuff, mirrored cache with battery backup, full software (including all future Sw, etc)
DELL-ToddM Sorry for using the wrong terms - Is it better to say Array?
Dell-Marc Its Ok, , but array is a better word.
Dell-Marc When people think of shelves, I think they think of a bunch of disks that connect to a controller somewhere. There are implications about that that don't fit the Equallogic design model
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DELL-ToddM I agree that it makes more sense to call them arrays
Dell-Marc If you can add lots of disks without adding controllers, you tend to boost capacity but hurt performance
DELL-ToddM Welcome Razec
Dell-Marc With a Ps5000 array, you add controllers, ports and cache along with disks, so that performance scales with capacity
DELL-ToddM And the beauty of the Equallogic software is able to make all the arrays work together easily
Dell-Marc Yep, that's a function of the distributed volume manager and higher level virtualization layers
DELL-ToddM Razec - We are just having a discussion about Equallogic and what it means to scale up
DELL-ToddM Feel free to jump in with any questions or comments
RAzec thanks,
DELL-ToddM Marc - It looks like I will be well positioned with the four Equallogic shelves
DELL-ToddM I mean arrays!
DELL-ToddM Old habits are hard to break sometime
DELL-ToddM As long as I don't refer to the management utility as Navi - I think we will be Ok....
Dell-Marc You'll be fine (I think) . We might have to shine the Mib light in your eyes. You'll be able to do an number of experiments in scaling - including using the systems's native thin provisioning
DELL-ToddM What does thin provisioning mean?
Dell-Marc Thin provisioning is a way to say you have more storage than you actually have
Dell-Marc The idea is to buy small knowing you'll need more later
Dell-Marc Its like credit - for storage capacity
DELL-ToddM So the hosts think that they have more storage than they do?
Dell-Marc exactly
Dell-Marc A lot of the times, admins don't have any idea how much capacity growth there will be and when, but they know its going to happen
Dell-Marc Thin provisioning allows them to spend less now and provision more later when they need it
RAzec and how it works , it is based based on predefined rules/thresholds?
Dell-Marc That way, they don't waste a bunch of valuable storage space waiting for an application (or system) to grow
Dell-Marc Its based on a couple things:
Dell-Marc The initial provision is based on a percentage of space you actually want to use
Dell-Marc Then there are thresholds, warnings and brakes that are applied as you reach capacity levels
Dell-Marc An admin has to add storage when needed, there is not an automated way to add more (that I know of)
RAzec right, probably you don't want to give to the system that level of automation..
Dell-Marc One thing that's cool about Equallogic's algorithm's is that if you want, you can take a volume that has been thin provisioned and turn it into a normal volume
RAzec on the fly?
Dell-Marc So if you start thin, then at some point add more - and say things stablilize or the application is not beiong used as much, you can convert it to a normal volume and remove the risk of over-extending "credit"
Dell-Marc Yes, on the fly
Dell-Marc Obviously there has to be sufficient space available.
Dell-Marc Another thing that you'll find interesting is the interlock between snapshot capacity and thinly provisioned volumes. Allocated capacity for snapshots are automatically adjusted as additional capacity is added to a thinly provisioned volume
DELL-ToddM Very cool - Does it include the check for the needed space for snapshots, when you add capacity to the thin provisioned volume?
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Dell-Marc Hey, todd is it ::beer time for you yet?
DELL-ToddM It is a bit past time for me!
DELL-ScottH it sure is when Stuart joins, then we know it;s beer time !
Stuart Hehehe
DELL-ScottH ::beer
DELL-ScottH doh, that was loud !
DELL-ToddM This was the last of the three week series on iscsi chats - next week we are starting a series of Hyper-v management chat
Stuart 7am over there.... so about 10hours to go for me... before /beer
Dell-Marc Cool
Dell-Marc I don't mean cool that you have to wait so long.....
DELL-ScottH We also have a special chat on tuesday for Flexaddress that is geared for the european timezones
DELL-ScottH 9am our time Gmt-5
RAzec are you plan to cover vmware any time soon..
DELL-ToddM Yes - Techcenter Chats go global next Tues!
DELL-ScottH vmware mgmt ? or vmware in general ?
RAzec I;m intereseted on Esx/baldes...
DELL-ToddM We have done a number of Vmware related chats in the past and we are always looking for new topics
RAzec ok , I'll take a look..
DELL-ToddM Esx Blades - We are working on a Blades Extravangaza topic to follow the Hyper-v stuff
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RAzec ah nice..
DELL-ToddM So we will definately have a chat in that time frame that will cover you
DELL-ScottH I'd say do it, yes Blades topic starts aug 4th ... but don't wait until then, ask questions on the techcenter site anytime
DELL-ToddM In the mean time - you can submit questions on any Techcenter page - at the bottom in the comments area
RAzec thanks, I'm newbie.. so...
DELL-ScottH yes ! noobs rule !
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DELL-ScottH welcome to the site
Dell-Marc Todd, Btw, I just saw the Q on thin provisioning and snaps: The system add add'l snap space when space is added to a thinly provisioned volume
DELL-ToddM I would like to give a big thanks to Marc and Travis for helping out with the iscsi topics!
RAzec thanks
Dell-Marc Thanks for having us (well me anyway)
DELL-ScottH thanks for the good times and beers
Dell-Marc Travis, ::punk where are you?
DELL-ToddM I'm a recoverring Fibre Channel guy and they still talk to me :-)
Stuart Yeah guys, thanks! it was a great session!!!..... I only wish i had been here... :)
Dell-Marc Yes, you and your old world lexicon
Dell-Marc that was for todd
DELL-ScottH gutenberg would be proud
DELL-ToddM Ah the ole world
Dell-Marc go go gutenberg
DELL-ScottH thank ye for having us
Dell-Marc If only he had beer icons back in the day
DELL-ScottH he was so close to inventing the smiley
DELL-ToddM I've gotta drop off - But thanks to all for attending. (gotta go create some Hyper-v Vms)
DELL-ScottH bring out the farm animals !
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DELL-ScottH thanks !
RAzec :) testing, see ya..
Dell-Marc Thanks everybody
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Stuart Seeya guys :)
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