What's a Passive Server?

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 719898

    Comments posted to this topic are about the item What's a Passive Server?

  • Malcolm Daughtree

    SSCrazy

    Points: 2373

    Passive... is a very relative term But, as far as SQL server licencing is concerned if you are 'using' it even readonly or DBA activity then this is deemed a 'Production server'. I know this is also an over used term but the only 'passive server' that doesn't need a licence applied is a mirrored server in the pure sense of the word. The area that is hitting the DBA at the moment is the understanding what Mircosoft refer to as 'Data mobility'. There is not one answer. Trust me, we've been tooing and froing with our licence provider over this for a long time. Their original bill was, to say the least, un-believable and 6 week later we have managed to cut it by two thirds, the CIO is happy. There is no one answer and the calulation is convoluted for instance.

    Case 1. (I'm using rough figures $10K per STD, $30K per Enterprise, datacenter I'm not even going there.....)

    1 SQL Standard installation on a dual quad core server = 1 licence per Physical CPU (black plastic on the motherboard) hence $10K X 2 = $20K.

    Case 2

    The same SQ server install on a Virtual server using the cores per cpu division rule, need only 1 licence, working like this

    1 SQL std using 2 Virtual CPU's (on a dual quad core host) 2 / 4 is less than 1 there only 1 licence. As common sense would dictate in that in a virtual environment you don't get to use all the horse-power of the CPU there MS uses that number of Vcpu's/the number of cores to determine the license count required. Therefore only $10K .... Ahhh I hear you say well we'll just put all the SQL servers on one host, give them 4 VCPU's "huzzar" I hear you say, 'supedup SQL servers', and to a point that can work. But remember you can only fit 5 Lbs of excretment in a 5 Lb bag and if start over subscribing the Host then you are in a world of hurt.

    I hear the ESX/Hyper V boys and girls going "but we have dynamic resource allocation and clustered ESX hosts with 24 cores and 196Gig of RAM, not a problem." -- Wrong !! Because if left to the defaults and you let you virtual environment management move the "SQL Server" or "OSE (operating system environments)" as MS describes between host and because the STD edition doesn't have this licence mobility, the calculation is very VERY different.

    1 STD SQL Server with 2 vCPU's with 3 possible hosts equals 2/4 there 1 license x 3 possible locations by $10K = $30K . Now do the same calulation with Enterprise Edition(licensing the vCPU's) 1 Ent using 2/4 = 1 licence with 3 possible hosts = 1 x $30k x 3 = $90K.

    Don't just take my word for it check this out http://tonymackelworth.wordpress.com/category/sql-server/

    This is not a new thing as this licensing model was introduced in 2008.

    The break even point is when you calculate the cost of an Enterprise license per physical CPU model eg 6 Physical CPU ESX host where each is licenced starts looking competitive 6 x $30K = $180 K with each licence you can install 4 OSEs, up to enterprise edition, therefore 24 STD editions if licenesed individually would be 24 x $10K = $240K. In our environment this worked, yours will be different.

    There are so many variations that each environment needs to be investigated taking into account the virtual hosts, High availability options used, a whole raft of things.

    BTW the new version of ESX (4.0) has migration rules that can be utililised to prevent migration between host groups and there by possibly reducing your TCO of SQL server.

    Have fun. This is the brave new world-Virtually.

    CodeOn 😛

  • chrisn-585491

    SSCoach

    Points: 15896

    The only "Passive Server" would be one that had no-commercial software requiring paid licenses. This would exclude any offering from Microsoft, Oracle, IBM, etc, but I believe PostgreSQL running on Linux could be consider "passive", no matter the load... 😛

  • getoffmyfoot

    Hall of Fame

    Points: 3052

    chrisn-585491 (2/1/2011)


    The only "Passive Server" would be one that had no-commercial software requiring paid licenses. This would exclude any offering from Microsoft, Oracle, IBM, etc, but I believe PostgreSQL running on Linux could be consider "passive", no matter the load... 😛

    I totally second that. Postgres + linux = who cares what's "passive"?

  • Bob Matthews

    SSC Veteran

    Points: 208

    Microsoft's licensing is all so ridiculously complicated that they offer a full day course in it! Software licenses should take up no more space than Steve's daily editorial.

  • kswartze

    SSC Enthusiast

    Points: 155

    Steve,

    I find that after reading "What's a Passive Server?", I still don't know what a passive server is. The only bone you threw us was at the very end where you say it's a server "not doing any work..." So what exactly does that mean?

    I assume a passive server delivers some value or we wouldn't be talking about it. What is the value of the passive server and why would I have one? Is it for backup/redundancy only? If the server is storing retrievable data then I would argue that it's doing the most basic work that a db can do. Please elaborate.

  • Ron Porter

    Ten Centuries

    Points: 1008

    Without getting into the definition of a passive server, here's the way I think it should work.

    That disaster-recovery (DR) or high-availability (HA) server does have value because it serves a very real business need. That strikes me as being worth paying for. Given that they are not accessible to the users in their normal state, it seems to me that the licensing cost should be dramatically reduced. Obviously, those servers need to be managed and maintained if they are going to serve their purpose and it seems reasonable to say that they will only be put into full service when the other server(s) go down.

    That leads me to conclude that those kinds of servers should be licensed, but at dramatically reduced cost. Naturally, the license should include the freedom to manage and maintain the server as necessary. Finally, since these servers are going to be put into full service only when something else is down, planned or otherwise, I would like to see the 'full' license of downed server be sufficient for temporary operation or transferable for permanent operation.

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 719898

    kswartze (2/1/2011)


    Steve,

    I find that after reading "What's a Passive Server?", I still don't know what a passive server is. The only bone you threw us was at the very end where you say it's a server "not doing any work..." So what exactly does that mean?

    Somewhat the point of the editorial. I still don't know either. It appears that there isn't a good definition from Microsoft on what this is. If I find one, I'll post it.

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 719898

    Ron Porter (2/1/2011)


    ... Finally, since these servers are going to be put into full service only when something else is down, planned or otherwise, I would like to see the 'full' license of downed server be sufficient for temporary operation or transferable for permanent operation.

    My understanding is that if you have a passive server (whatever that is), handling your mirroring or clustering, if it takes over the load, it becomes the "active" server and the license moves. However I'm not sure how the clause mentioned in the editorial applies.

  • Ron Porter

    Ten Centuries

    Points: 1008

    Steve Jones - SSC Editor (2/1/2011)


    Ron Porter (2/1/2011)


    ... Finally, since these servers are going to be put into full service only when something else is down, planned or otherwise, I would like to see the 'full' license of downed server be sufficient for temporary operation or transferable for permanent operation.

    My understanding is that if you have a passive server (whatever that is), handling your mirroring or clustering, if it takes over the load, it becomes the "active" server and the license moves. However I'm not sure how the clause mentioned in the editorial applies.

    Most of what I said is purely theoretical. As yet, I've never worked on any system where there were mirrors or anything else that could be called a passive server, regardless of how that might be defined. Between the article and some of the comments, I was led to think that the license wouldn't follow the action (in the sense of 'active server', again, whatever that might be :))

  • kswartze

    SSC Enthusiast

    Points: 155

    Steve Jones - SSC Editor (2/1/2011)


    kswartze (2/1/2011)


    Steve,

    I find that after reading "What's a Passive Server?", I still don't know what a passive server is. The only bone you threw us was at the very end where you say it's a server "not doing any work..." So what exactly does that mean?

    Somewhat the point of the editorial. I still don't know either. It appears that there isn't a good definition from Microsoft on what this is. If I find one, I'll post it.

    Would it be fair to say that, without an understanding of what a passive server is, you can't have a meaningful opinion about how it should be licensed? We all seem to agree that licensing costs should somehow correlate to value or load. When you use log shipping, mirroring, or clustering, you do it for added value--you benefit in some way by having that copy of SQL up and running. I don't see why those additional servers should be free (Discounted? We can talk!). If you have a copy of SQL server that truly has no value, scrap it and pay nothing.

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 719898

    I don't know quite how a passive server is defined, but all the MS documents seem to say that you get at least one passive server for your HA options.

    The benefit you get is like insurance in case something happens, but unlike insurance, we can't buy a heavily discounted license.

    My reading is that if I have a server that is sitting there, just receiving mirror updates or restoring log shipped backups, or is a passive node in a cluster, I don't need a license for it. That seems reasonable to me.

    If I used that server to server clients outside of the active node, then I must license it. If I have two servers I log ship backups to, then I must license one of them. I'm not sure I like that, but that's how I read things.

    What I don't know is can I setup all my internal monitoring on these servers and still call them passive? Or can I run dbcc's to verify my production machine and call that passive? Can I "move" a passive license from a cluster with 3 active and only one passive node to allow me to have a second log shipping option. Those are where it gets confusing for me.

  • Evil Kraig F

    SSC Guru

    Points: 100851

    My understanding of the licensing, which admittedly has limitations, is that your failover target, and only that target, is the passive server.

    So, if you have four servers, 3 active 1 passive, and you have all 3 of them failing over to that one passive, you've used up their passives.

    Passive servers are meant to be there as the immediate takeover for an active. Nothing else. Maintenance ran on your primary can be ran on them as well, but using them as an alternate for your primary for any purpose other then as a failover target de-passives them, at least according to the license.


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  • Jeffrey Williams

    SSC Guru

    Points: 88539

    Steve Jones - SSC Editor (2/1/2011)


    What I don't know is can I setup all my internal monitoring on these servers and still call them passive? Or can I run dbcc's to verify my production machine and call that passive? Can I "move" a passive license from a cluster with 3 active and only one passive node to allow me to have a second log shipping option. Those are where it gets confusing for me.

    Well - first you need to realize that in a clustered environment you don't have access to the databases on the 'passive' node. Those resources are only available to the node currently hosting that instance of SQL Server.

    With mirroring, you have the same limitations - since you cannot access the databases while they are being mirrored.

    As long as there are no other active instances (clustering), or principal databases (mirroring) on the 'passive' node it does not need to be licensed.

    Now, the tricky part is what happens when you failover to the passive node. Does the license move with the instance to the other node? Or, are you required to fail back within 30 days? This is the bit that is confusing for me.

    Since licensing is now paper work only - I think (of course, I could be wrong) that as long as your are properly licensed for all active nodes in the cluster, then it doesn't matter which physical node is actually the 'passive' node.

    With mirroring, it gets a bit more complicated because you can failover a database only. Now, if you have 10 databases mirrored - and one of those databases is failed over to the 'passive' node - that node is no longer considered passive. I think this is where the 30 days comes in - such that you now have 30 days from that failover to bring that database back to the principal node or it must be licensed.

    That makes sense to me, but who knows for sure 😉

    Jeffrey Williams
    Problems are opportunities brilliantly disguised as insurmountable obstacles.

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  • mar10br0

    Say Hey Kid

    Points: 668

    When I pay the premium for a SQL server edition with fail-over capabilities, I consider having paid for the use (license) of those capabilities!

    No matter how I choose to implement it on my hardware, I use the built-in capabilities of the license. Full stop.

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