14 Replies Latest reply on May 11, 2009 3:07 PM by DirtySouth

    Hardware recommendation?

    warbird

      I am looking to build a better standalone SQL server.  Current system is a Dell 2950 with six 7200 RPM SATA drives (slooooow) in a RAID 10 array.  The OS lives on the same array as the SQL db.  Also, current server has only 8 GB RAM and is running 32 bit Enterprise Server with AWE enabled.

      Here are my options for a new server:

      24 or 32 GB RAM, eight 15K rpm 146 GB 2.5" SAS drives.  6 would be RAID 10'd for the SQL db to live on, the other two would be RAID'd for the OS to live on.

      24 or 32 GB RAM, six 15K rpm 450 GB 3.5" SAS drives.  All 6 would be in the RAID 10 array but the OS would have to live on the same array as the SQL db.

      Which is better?  Old school was always better to have OS living on different drives.  However, if I do that, I take a huge space hit, as I'd only have about 400 GB of space available for the SQL db.  that should be plenty, but still...

      Help?  Is it important to have the OS not live in the same RAID array as the db??  I need to get this quote to my boss, ASAP. 

      TIA,

      warbird

        • Re: Hardware recommendation?
          qle

          I don't know if you have an established standard or policy regarding the configuration of your servers but since you posed this question, it sounds like you have an option here. It's been my personal opinion to separate OS and data wherever possible. If you need to completely rebuild the OS for some reason, it's some comfort that this configuration will minimize any risk of corruption to the data.

          It's a little ironic that you're worried about taking a hit on storage space while you'll be setting this up as RAID 10, though. ;)

          • Re: Hardware recommendation?
            vhcato

            Given a choice between the two options presented, I would have to go with #1. Keeping the OS separated on their own pair of disks (RAID 1), and the other 6 as a RAID 10 array for the DB should provide a significant improvement in performance given the obvious differences in the current and new hardware. Of course, that is if you are truly running into a disk IO bottleneck, and I assume you are.

            As for the memory, more is deffinitely better. Also, make sure you invest in a good array controller.

              • Re: Hardware recommendation?
                warbird

                Thanks, vhcato.  Yes, I was running into extreme I/O problems with the current disks, especially when they were in RAID 5.  I was seeing average disk queue lengths between 400 - 800, just with NPM and NCM (NTA disabled).  Changing over to RAID 10 got the avg disk queue length down to about 200.  A couple of config changes in the NCM got it bouncing between 100 - 150.  Enabling AWE (the SQL server is currently 32 bit) reduced the queue length to below 5!  However, running NTA for any length of time introduces problems again.

                I believe this new hardware for the SQL server should allow us to run NTA, although I do have a concern about how large the netflow portions of the db will get.

                *edit* Forgot to include that because the server is a Dell, I am restricted to going with one of their PERC 6/E RAID controllers.  I am going for the one with 512 MB cache.

                  • Re: Hardware recommendation?
                    vhcato

                    Yes, netflow data can definitely put a hurt'n on a disk array, as well as CPU's. Unfortunately, I'm not familiar with with the requirements of NTA, as we use a different product for our netflow needs, but depending on your data retention requirements, flow rates, and the number of interfaces/devices from which you're receiving flow data, this could require substantial server resources to store the info and present it in a timely manner.

                      • Re: Hardware recommendation?
                        DirtySouth

                        SQL servers in general would benefit from data in a raid 10 and OS in a raid 1. Were using a 2950 for our SQL server as well with 4 drives in a raid 10 and two in a raid 1. Performance seems fine.

                          • Re: Hardware recommendation?
                            warbird

                            DirtySouth,

                            How much RAM does your SQL server have and are you using NTA (netflow), as well?

                              • Re: Hardware recommendation?
                                DirtySouth

                                DirtySouth,

                                How much RAM does your SQL server have and are you using NTA (netflow), as well?

                                4GB RAM and no Netflow. This box has a few other small databases on it as well. We've got NPM, NCM & APM, with a total of 951 nodes, 1298 interfaces and 946 volumes. Surprisingly we average about 60% physical memory and 10% CPU utilization.

                                I think we will need to eventually upgrade our App server though...the app & website are hosted on a single server and lately, the website is a little sluggish.

                                  • Re: Hardware recommendation?
                                    warbird

                                    Thanks.  You said you have 4 disks in a RAID 10 for the SQL db to live on.  What type of disks are they (SATA, SAS, ?)?

                                    I am running NPM, NCM, APM, and trying to run NTA.  I have 2 polling engines, a separate server for Cirrus to run on, and a dedicated SQL server that is probably going to get upgraded so it can handle the NTA.  Here are our current stats:

                                    Network Elements4016 Elements
                                    Nodes1062 Nodes
                                    Interfaces2765 Interfaces
                                    Volumes189 Volumes
                                      • Re: Hardware recommendation?
                                        DirtySouth

                                        Thanks.  You said you have 4 disks in a RAID 10 for the SQL db to live on.  What type of disks are they (SATA, SAS, ?)?



                                        6x 300GB SAS drives. How is your website performance? Is it fairly snappy? If you don't mind saying, what are the specs on your polling engines (app servers)? Were just using a single polling engine.



                                          • Re: Hardware recommendation?
                                            warbird

                                            Ah, yes.  The SAS drives in your SQL server are what is making it all work well for you, IMO (and you are likely utilizing a good deal of RAM).  We are running 7200 RPM SATA drives and after all the research I've done, I am surprised they are performing as well as they are, even in the RAID 10.  I can't wait to get 6 of the 15K RPM SAS drives in a RAID 10 dedicated to the SQL db.

                                            Our website performance is okay.  Depends on what you mean by 'snappy'.  An auto refresh generally takes anywhere from 4 - 10 seconds.  Going from the NTA summary page back to the 'home' page takes slightly longer, maybe 10 - 15 seconds, depending.  We have quite a bit on our home page.  Before I started working on this (when the avg disk queue length on my SQL server was bouncing between 400 - 800), the web page would take 45 - 60 seconds to refresh (or more) and would often fail (map wouldn't load, errors, etc).

                                            Our primary polling engine is a Dell PowerEdge 1955 with 2 dual core 3 Ghz Xeon CPUs and 8 GB of RAM.  It is rarely stressed, even with the NetFlowService turned up.  We have the 4000 elements split up fairly evenly between the two polling engines.

                                            My hope is that the beefier SQL server with faster disks and more RAM will make the web page a little more snappy and overall performance with NetFlow running much, much better.  This is what I've promised my boss, so here's hoping.  ;)