On Fri, Mar 09, 2012 at 10:56:24AM -0500, Jorge Luis Diaz Flores wrote: > Sorry, it is very difficult if not impossible for me to say something > about the add-ons with that amount of information. Yes, we can only talk in generalities. But, here goes. > >>> ? ? ? ? ? High Availability > >>> ? ? ? ? ? Resilient Storage > >>> ? ? ? ? ? Load Balancer > >>> ? ? ? ? ? Scalable File System Add-On > >>> ? ? ? ? ? High Performance Add-On > >>> ? ? ? ? ? Smart Management Add-On To answer this, you would need to know what you're going to do with them, and also how critical it is for you not to have any downtime. Don't you already have storage? You said you just got some NetApps. Are resilient storage and scalable file system already included in your NetApps? ... do you even need those things? You can get "resilient storage" from raid configurations and scalable filesystems (I mean resizable, I don't know what Red Hat means) from LVM, I'd guess. Other things to contemplate: are you going to be generating a _lot_ of little files, or any really big (bigger than 4GB) files? Those can be handled with Linux kernel config options. If you can tolerate downtime in maintenance windows, then perhaps you don't need high availability. Other things to contemplate: You will want to be able to talk to your UPS, there are S/W packages on Linux that do that (apcusd, nut are two that come to mind). You don't need a fancy add-on package for that. (See also Smart Management) Are you going to be stressing the machine's capabilities? If not, perhaps you don't need the high performance add-on. For Smart Management - I'm guessing it's some kind of GUI over the normal sysadmin tasks/functions and will likely produce management-ready reports. If you have time to mess with the system admin and produce such reports yourself, perhaps you don't need to buy the Add-On. On the other hand, if your time is already at a premium and you have cash to burn (as some gov't departments do just before April 1), you might want to opt for it. I haven't addressed the Load Balancer. I don't know how their Load Balancer works ... and whether you need it depends on what you're doing. Hmm, the Red Hat page says: "The Load Balancer Add-On balances the IP load across a set of physical servers based on a preordained algorithm, thus evenly distributing the load among available servers for maximum efficiency and high availability." so it seems it's for the case where you're running multiple copies of the same service on multiple IP addresses, or something. This is for when you have a lot of network accesses. I'd think this would be for things like Google search, or Facebook, or something. I have a hard time believing that the CRTC would need that themselves ... I suppose they might want to be up in spite of DDoS attacks or something. Before you buy anything else, decide on what your threat models are (ie, the threats you are going to defend against/mitigate) and only buy stuff to address those things. Otherwise, vendors will be pushing you to buy all kinds of stuff they say you need, but which in fact is stuff they need to sell. It is easier to say "no" to them when you have a plan of your own. Note that the only really secure system is one that you wrote all the software for (compilers included), and that is not connected to other computers (wired, wireless or sneakernet). Pretty useless, and time and resource consuming besides. You will have to decide on a risk level. It sounds trite to say, but don't buy defences against the risks you've decided aren't worth covering, and don't buy more than one defence against the risks you've decided are worth covering (unless you decided you wanted to cover that one in depth). Easier said than done, though. I hope this helps. And with luck some real sysadmins might correct me : - ) bjb