Re: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509

[Sanford Whiteman]

Well, FT and LB, though often conflated into one enterprise goal, are extremely different -- often mutually exclusive -- aims.  If you need to add FT to the mix, you'd need to cluster each involved server to provide N+1 hardware redundancy.  For systemwide FT, you need to use HSRP, AFT, etc.  It depends on how many faults you wish to tolerate...there really are very few resilient end-to-end systems.  Adding FT to the architecture would not be difficult, just costly.   As for the SQL Server questions:   (1) I was referring to the use of separate tables within the same database to hold user information for different servers, reducing maintenance load and system complexity.  The database could be hosted by a single clustered SQL Server, or partitioned across multiple clusters.  This does not involve replicating back-end data.  The same database cannot be served up by multiple servers, as you mentioned.   (2) SQL Server clusters can be active-active or active-passive.  In the former case, you can double potential performance in a pre-failover situation by using the resources of both machines.  However, benchmarking can be difficult, as while the servers will default to handling their own group of databases, either one will have to take over the workload of the other (in addition to its own) in the event of a system failure.  You usually end up coming down somewhere in the middle, not pushing either server to the limit in an active-active setup, but just trying to exceed by some percentage (50%) the performance of a single server.   Sandy -----Original Message----- From: John David M. Miller <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Wednesday, May 03, 2000 12:58 AM Subject: RE: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509 Sandy,   I re-read your original post and must admit that I found it confusing. Why would you need to segment your accounts? From a fault tolerance standpoint this would not appear to work. Regarding the use of multiple SQL tables, would this allow multiple SQL servers to use the same database? I was under the impression that SQL did not allow this. I am also under the impression that a SQL cluster (MS version) is active passive and provides failover only?   Your second post appears to clarify to a degree through the addition of the unmentioned pieces from your first post.       You wrote: "Yes, you *can* have just one exposed IP address -- this is the default behavior with HydraWEB, Radware, etc."   This caught my eye.   Does this require that every account be created in duplicate across the servers that make up the farm. In my proposed scenario each IMail server points to the same SQL server (individual, cluster, or LB farm) for authentication. Each server also points to the same NAS for data (message) storage.   From what I have seen in IMail it appears that only the domain itself would need to be created on each farm member. >From there SQL would define the accounts and any server could retrieve the data from the shared NAS. Persistent connection would be maintained via the L4 switch.   Is this accurate? It getting late and I am getting foggy. ;-)   TIA   John Miller SAMnet   -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Sanford Whiteman Sent: Tuesday, May 02, 2000 11:26 PM To: [EMAIL PROTECTED] Subject: Re: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509