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d3ng
Yak Posting Veteran
83 Posts |
 Posted - 2007-08-22 : 20:44:56
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| Hi SQL expert, I would like to ask regarding SQL Instance installation. I would like to know if I installed 2 different instances in my Server does performance would be an issue or it might cause for the server to slow down? The reason of splitting the 2 instances is because we want to separate our 2 system in two different instances instead of locating it in one instance. |
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eyechart
Master Smack Fu Yak Hacker
3575 Posts |
Posted - 2007-08-22 : 21:51:27
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| it all depends.if you were going to run both databases on this host in the first place, then I don't think there would be that much more additional overhead of running the 2nd instance. Here are some pros/cons for this configuration that I can think of right off the top of my head:Pros:1. two instances gives you greater control over memory allocations (give one instance 1GB and the other 2GB for example). THis is a huge benefit because now you can control the buffer cache allocation to each instance. This means that a reporting database that you host on the instance your OLTP environment is on will not monopolize the buffer cache causing perf headaches in your transactional environment.2. two instances allows you to use more of your system memory. If you are running standard edition sql server, you have a hard limit of 2GB of RAM accessible per instance. If you have a server with 6GB RAM, there is a great deal of memory that cannot be accessed with a single instance. Of course this point is meaningless if you are running 64bit SQL.Cons:1. greater cost. Unless you run Enterprise Edition SQL, you will need to get a server license for each instance of SQL you run on this server.2. You will need to use a named instance for your 2nd (or more) instance installed since only 1 default instance is allowed per server. This can be a little confusing if you are new to named instances.3. queries across instances are more difficult. You will have to use linked servers in order to join data from one instance with data in another. Single instance setup makes this type of thing much easier.4. Multiple instances can be confusing when trying to troubleshoot performance. for example, you notice that the sqlservr process is taking 100% cpu - which instance is the culprit?OK, so these are pretty trivial problems and they all can be worked around. I work in an environment where we have 8+ instances per host in a multiple cluster environment so I am quite familiar with all of this. Personally, I think that running multiple instances is of great benefit if you are doing it for sound reasons - otherwise you are just complicating things.-ec |
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rmiao
Master Smack Fu Yak Hacker
7266 Posts |
Posted - 2007-08-22 : 22:00:36
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| If you run multiple instances on 32-bit server, memory allocation is a big issue. |
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SQL Instance Installation