ML
    • Recent
    • Categories
    • Tags
    • Popular
    • Users
    • Groups
    • Register
    • Login

    Configuration for Open Source Operating systems with the SAM-SD Approach

    SAM-SD
    5
    51
    11.8k
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • scottalanmillerS
      scottalanmiller @GotiTServicesInc
      last edited by

      @GotiTServicesInc said:

      In my research I may have confused dual channel raid controllers with dual controllers.

      Definitely different things. One is more or less just for SAS level channel throughput. The other is for redundancy at the controller level (in theory.)

      1 Reply Last reply Reply Quote 0
      • G
        GotiTServicesInc @Dashrender
        last edited by

        @scottalanmiller said:

        @GotiTServicesInc said:

        In my research I may have confused dual channel raid controllers with dual controllers.

        Definitely different things. One is more or less just for SAS level channel throughput. The other is for redundancy at the controller level (in theory.)

        Yeah I think I just had a brain fart when going over that, I understand the differences between it but got lost in the sauce swimming between the two topics heh

        1 Reply Last reply Reply Quote 0
        • G
          GotiTServicesInc
          last edited by

          so really a HA SAN for an enterprise wouldn't really be more than 2 ish SANs? And more than that you would go for more of a RAIN setup?

          I figured duplication over a network even with 40GB pipes would still be painful but wasn't sure

          scottalanmillerS 1 Reply Last reply Reply Quote 0
          • scottalanmillerS
            scottalanmiller @GotiTServicesInc
            last edited by

            @GotiTServicesInc said:

            I know for current leads in our company they're requesting a dual controller box, but being that this box is operating by itself I'm assuming with the additional controller they're buying a bit more redundancy for that.

            You don't do dual controllers for protection, not in the real world. RAID controllers do very bad things when you pair them up, that's why enterprise servers don't ship that way, ever. Not even $100K servers are like that. And that's why dual controllers in SMB range SANs are bad, they actually cause outages rather than protecting against it.

            One of the most important reads here is: Understanding the Relationship of Reliability and Redundancy

            Reliability is the goal, redundancy is a tool. In this case, your redundancy would not support your goal so isn't a viable option.

            1 Reply Last reply Reply Quote 0
            • scottalanmillerS
              scottalanmiller
              last edited by

              In your OP you said dual SAS controllers, that is how this is handled for high end enterprise servers $50K and up. The high end doesn't use RAID controllers at all, only SAS. SAS controller with software RAID can do the redundancy that can't be done with what is on the market for RAID controllers well.

              DashrenderD 1 Reply Last reply Reply Quote 0
              • G
                GotiTServicesInc
                last edited by

                I assumed SAS has built in raid which I realize now was a bad assumtion. dual controllers would just be used to increase the number of drives you could stick in a box then which makes more sense.

                scottalanmillerS 1 Reply Last reply Reply Quote 0
                • scottalanmillerS
                  scottalanmiller @GotiTServicesInc
                  last edited by

                  @GotiTServicesInc said:

                  so really a HA SAN for an enterprise wouldn't really be more than 2 ish SANs? And more than that you would go for more of a RAIN setup?

                  Correct, enterprise SANs have traditional always been "scale up" or "vertical scaling" devices. Your size is determined by how big a single SAN can go. HA is provided by a combination of mainframe class design and features and mirroring to a second SAN. That's all we've ever had traditionally.

                  Moving to scale out systems is very and very niche still. Using scale out with SAN is still relatively rare and problematic. The first vendors are just starting to get their footing on this and there are generally performance issues.

                  1 Reply Last reply Reply Quote 0
                  • DashrenderD
                    Dashrender @scottalanmiller
                    last edited by

                    @scottalanmiller said:

                    In your OP you said dual SAS controllers, that is how this is handled for high end enterprise servers $50K and up. The high end doesn't use RAID controllers at all, only SAS. SAS controller with software RAID can do the redundancy that can't be done with what is on the market for RAID controllers well.

                    So with the OP, would the question be more like, which RAID level should I use over all theses drives in software, vs one controller RAIDed against the other controller?

                    And would a SAM-SD really look at skipping hardware RAID for software?

                    MattSpellerM G 2 Replies Last reply Reply Quote 0
                    • G
                      GotiTServicesInc
                      last edited by

                      I did skim that but wasn't sure where the risk vs. reward scale crossed in regards to RAID

                      1 Reply Last reply Reply Quote 0
                      • scottalanmillerS
                        scottalanmiller @GotiTServicesInc
                        last edited by

                        @GotiTServicesInc said:

                        I assumed SAS has built in raid which I realize now was a bad assumtion. dual controllers would just be used to increase the number of drives you could stick in a box then which makes more sense.

                        SAS and SATA are the protocols that storage uses to communicate. RAID controllers talk SAS and/or SATA, but most controllers do this without having hardware RAID.

                        You don't use multiple controllers for more drives. There isn't any normal server on the market that goes beyond what a single controller can handle. A single good controller will do hundreds of drives.

                        1 Reply Last reply Reply Quote 0
                        • MattSpellerM
                          MattSpeller @Dashrender
                          last edited by MattSpeller

                          @Dashrender well, if it's not running other apps on the OS why save the CPU with a RAID card?

                          edit: I just realized you were tl;dr'ing, sorry - this post was for OP

                          1 Reply Last reply Reply Quote 0
                          • G
                            GotiTServicesInc @Dashrender
                            last edited by

                            @Dashrender said:

                            @scottalanmiller said:

                            In your OP you said dual SAS controllers, that is how this is handled for high end enterprise servers $50K and up. The high end doesn't use RAID controllers at all, only SAS. SAS controller with software RAID can do the redundancy that can't be done with what is on the market for RAID controllers well.

                            So with the OP, would the question be more like, which RAID level should I use over all theses drives in software, vs one controller RAIDed against the other controller?

                            And would a SAM-SD really look at skipping hardware RAID for software?

                            That may have been more of what I was looking for but didn't know how to ask the question

                            1 Reply Last reply Reply Quote 0
                            • G
                              GotiTServicesInc
                              last edited by

                              so why do they make boxes with dual controllers in them then ? I'm referring to your favorite, Nexsan @scottalanmiller

                              DashrenderD 1 Reply Last reply Reply Quote 1
                              • DashrenderD
                                Dashrender @GotiTServicesInc
                                last edited by

                                @GotiTServicesInc said:

                                so why do they make boxes with dual controllers in them then ? I'm referring to your favorite, Nexsan @scottalanmiller

                                This seems like an obvious answer - which I'm going to say is money- because they can sell them. But I'm sure Scott will correct me if I'm wrong on that.

                                1 Reply Last reply Reply Quote 0
                                • scottalanmillerS
                                  scottalanmiller
                                  last edited by

                                  So a brief Introduction to Hardware and Software RAID.

                                  Pretty much you use hardware RAID when...

                                  • you run Windows, HyperV or ESXi on the bare metal.
                                  • you want blind drive swaps in a datacenter.
                                  • you lack the operating system and/or software RAID experience or support to use software RAID.
                                  • you just want a lot of convenience.
                                  DashrenderD 1 Reply Last reply Reply Quote 0
                                  • scottalanmillerS
                                    scottalanmiller
                                    last edited by

                                    Reasons 1 and 2 (OS/HV choice and blind drive swaps) represent nearly every case as to why hardware RAID is chosen and legitimately make hardware RAID a nearly ubiquitous choice in the SMB.

                                    1 Reply Last reply Reply Quote 1
                                    • DashrenderD
                                      Dashrender @scottalanmiller
                                      last edited by

                                      @scottalanmiller said:

                                      So a brief Introduction to Hardware and Software RAID.

                                      Pretty much you use hardware RAID when...

                                      • you run Windows, HyperV or ESXi on the bare metal.
                                      • you want blind drive swaps in a datacenter.
                                      • you lack the operating system and/or software RAID experience or support to use software RAID.
                                      • you just want a lot of convenience.

                                      For the relatively small cost of a RAID controller, there are a lot of reasons to use one.

                                      scottalanmillerS 1 Reply Last reply Reply Quote 0
                                      • scottalanmillerS
                                        scottalanmiller @Dashrender
                                        last edited by

                                        @Dashrender said:

                                        For the relatively small cost of a RAID controller, there are a lot of reasons to use one.

                                        And most people agree and buy them. It's generally a no brainer in the SMB. For me, it's reason 2. I want everyone to have blind swap. Can't overstate how valuable that is in the real world.

                                        1 Reply Last reply Reply Quote 2
                                        • scottalanmillerS
                                          scottalanmiller
                                          last edited by

                                          Are you thinking that you will do software RAID between cluster nodes in this example above? I'm unclear if we are looking at up to three layers of RAID (hardware then software then network?) That's getting extreme.

                                          1 Reply Last reply Reply Quote 0
                                          • G
                                            GotiTServicesInc
                                            last edited by

                                            I wasn't sure how far you would really need to take for mission critical data. I was assuming that at some point you only want the data mirrored once. Whether that was mirrored at the drive level or at the system level I wasn't sure. I'm assuming if you have huge storage arrays you'd want to have two SANs with JBOD Arrays, mirrored across each other? or would you want to have a RAID6 setup in each SAN and then each SAN mirrored to each other? this way (like we talked about earlier) you can have a few drives go bad and not have to rebuild the entire array. In my mind the second way (with RAID 6) seems to make the most sense?

                                            scottalanmillerS 1 Reply Last reply Reply Quote 0
                                            • 1
                                            • 2
                                            • 3
                                            • 1 / 3
                                            • First post
                                              Last post