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    Deciding Between Hardware and Software RAID in My FreeNAS Deployment

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    zfs freenas freebsd storage hardware raid software raid raid
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    • S
      saniplastic @scottalanmiller
      last edited by

      This post is deleted!
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      • S
        saniplastic @scottalanmiller
        last edited by

        @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

        @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

        in my freenas server, each disk is on Raid0 Hardware Raid P410i

        How much cache does this have?

        1G

        1 Reply Last reply Reply Quote 0
        • S
          saniplastic @scottalanmiller
          last edited by saniplastic

          @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

          Cache-less RAID of any sort is all but useless

          thanks for reply

          before The more I read, the more I get confused :

          FreeNAS® 11.2- User Guide, Release 11.2 in page 322 says that:

          "ZFS was designed for commodity disks so no RAID controller is needed. While ZFS can also be
          used with a RAID controller, it is recommended that the controller be put into JBOD mode so that ZFS has full control of the disks"

          it says it is not needed ( not explicitly don't use ) and While ZFS can also be used with a RAID controller.

          and in page 110 says that:

          To prevent problems, do not enable the S.M.A.R.T. service if the disks are controlled by a RAID controller. It is the job of the controller to monitor S.M.A.R.T. and mark drives as Predictive Failure when they trip.

          it means this is possible to use RAID controller by freenas

          But in freenas forum every time you ask for Hardware RAID and zfs , all strictly says NO, DO NOT DO THAT.
          When I read your article, I was happy to find out.

          I use P410i (1G chache) on DL380 G7 and as i said raid0 each drive and present separate raid0 to freenas.
          i have one mirror pool and one Raidz1 pool and one Raidz2 pool.

          If I understand well because raid controller have 1G cache i should use Hardware RAID and present one logical drive to freenas and not using zfs raid.

          am i right?

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

            This thread covers exactly what you are asking about.
            https://mangolassi.it/topic/12047/zfs-is-perfectly-safe-on-hardware-raid/

            S scottalanmillerS 2 Replies Last reply Reply Quote 0
            • DashrenderD
              Dashrender
              last edited by

              The thing that I'm surprised hasn't happened yet is - Why hasn't @scottalanmiller asked why you're using FreeNAS instead of just using a Linux Distro and enabling sharing? (i.e. NFS or SAMBA)

              scottalanmillerS 1 Reply Last reply Reply Quote 1
              • S
                saniplastic @Dashrender
                last edited by saniplastic

                @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                This thread covers exactly what you are asking about.
                https://mangolassi.it/topic/12047/zfs-is-perfectly-safe-on-hardware-raid/

                i read that several time and find out zfs can implement on top of the raid controller.but can not get my answer related to my question.

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

                  @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                  This thread covers exactly what you are asking about.
                  https://mangolassi.it/topic/12047/zfs-is-perfectly-safe-on-hardware-raid/

                  that's where this was originally posted. But the question wasn't if it was safe, but which was better given the specific situation. Since both are options.

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

                    @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                    The thing that I'm surprised hasn't happened yet is - Why hasn't @scottalanmiller asked why you're using FreeNAS instead of just using a Linux Distro and enabling sharing? (i.e. NFS or SAMBA)

                    Because it's already in use and not part of the question.

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

                      @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                      @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                      This thread covers exactly what you are asking about.
                      https://mangolassi.it/topic/12047/zfs-is-perfectly-safe-on-hardware-raid/

                      i read that several time and find out zfs can implement on top of the raid controller.but can not get my answer related to my question.

                      I'm pretty sure that I answered your question here in this thread... unless you have weird stuff going on (all of which I outlined), the hardware RAID is going to be way better for you... basically for all of the reasons that the ZFS crowd claims it to be worse. All of the features that they point out with ZFS that requires that you not have hardware RAID, hardware RAID gives you as long as you don't use ZFS for software RAID 🙂

                      The one thing that you should avoid is using ZFS software RAID on top of a RAID controller that can't do pass through - that's the one situation where the error detection and tools are split and can't do their job from either side. Both protection mechanisms get bypassed. Should be one or the other.

                      1 Reply Last reply Reply Quote 2
                      • DashrenderD
                        Dashrender @scottalanmiller
                        last edited by

                        @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                        @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                        The thing that I'm surprised hasn't happened yet is - Why hasn't @scottalanmiller asked why you're using FreeNAS instead of just using a Linux Distro and enabling sharing? (i.e. NFS or SAMBA)

                        Because it's already in use and not part of the question.

                        If that was true - then there would be no point in the question because the decision of RAID on HW or not would be already decided - well i suppose FreeNAS could have been installed on a separate disk, then the actual storage be on the RAID attached drives.. but that seems like over kill.

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

                          To follow up to an offline request for more info...

                          Why do you need to avoid splitting RAID duties between a controller, and ZFS?

                          First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

                          Now, why is this?

                          In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

                          So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

                          Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

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

                            @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                            @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                            @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                            The thing that I'm surprised hasn't happened yet is - Why hasn't @scottalanmiller asked why you're using FreeNAS instead of just using a Linux Distro and enabling sharing? (i.e. NFS or SAMBA)

                            Because it's already in use and not part of the question.

                            If that was true - then there would be no point in the question because the decision of RAID on HW or not would be already decided -

                            No, because you skipped over the and portion. Yes, the split HW RAID and ZFS Software RAID is already in use, but it is the whole question.

                            1 Reply Last reply Reply Quote 0
                            • S
                              saniplastic @scottalanmiller
                              last edited by

                              @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                              To follow up to an offline request for more info...

                              Why do you need to avoid splitting RAID duties between a controller, and ZFS?

                              First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

                              Now, why is this?

                              In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

                              So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

                              Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

                              thanks all for reply

                              so i need:
                              1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
                              2-disable S.M.A.R.T service.
                              3-just use file system and not software RAID system of zfs.

                              scottalanmillerS ObsolesceO DashrenderD 3 Replies Last reply Reply Quote 2
                              • scottalanmillerS
                                scottalanmiller @saniplastic
                                last edited by

                                @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
                                2-disable S.M.A.R.T service.
                                3-just use file system and not software RAID system of zfs.

                                Yes, that's what I would do here. Simple, safe, effective.

                                1 Reply Last reply Reply Quote 1
                                • ObsolesceO
                                  Obsolesce @saniplastic
                                  last edited by

                                  @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                  1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.

                                  Just an FYI: it's not a backup when it's the only data. If you back up your VMs, then delete the originals, you no longer have a backup. All you have then is original data with no backup! Proceed wisely.

                                  S 1 Reply Last reply Reply Quote 4
                                  • S
                                    saniplastic @Obsolesce
                                    last edited by

                                    @Obsolesce said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                    @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                    1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.

                                    Just an FYI: it's not a backup when it's the only data. If you back up your VMs, then delete the originals, you no longer have a backup. All you have then is original data with no backup! Proceed wisely.

                                    you right

                                    i should have 2 series of backup.
                                    thanks

                                    DustinB3403D 1 Reply Last reply Reply Quote 0
                                    • DashrenderD
                                      Dashrender @saniplastic
                                      last edited by

                                      @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                      @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                      To follow up to an offline request for more info...

                                      Why do you need to avoid splitting RAID duties between a controller, and ZFS?

                                      First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

                                      Now, why is this?

                                      In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

                                      So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

                                      Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

                                      thanks all for reply

                                      so i need:
                                      1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
                                      2-disable S.M.A.R.T service.
                                      3-just use file system and not software RAID system of zfs.

                                      Where are you disabling SMART?

                                      scottalanmillerS S 2 Replies Last reply Reply Quote 0
                                      • scottalanmillerS
                                        scottalanmiller @Dashrender
                                        last edited by

                                        @Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                        @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                        @scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                        To follow up to an offline request for more info...

                                        Why do you need to avoid splitting RAID duties between a controller, and ZFS?

                                        First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

                                        Now, why is this?

                                        In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

                                        So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

                                        Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

                                        thanks all for reply

                                        so i need:
                                        1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
                                        2-disable S.M.A.R.T service.
                                        3-just use file system and not software RAID system of zfs.

                                        Where are you disabling SMART?

                                        In the OS, I assume.

                                        1 Reply Last reply Reply Quote 0
                                        • matteo nunziatiM
                                          matteo nunziati
                                          last edited by

                                          Smart should simply fail as in a vm. I don't think you need to disabile it.

                                          scottalanmillerS 1 Reply Last reply Reply Quote 0
                                          • DustinB3403D
                                            DustinB3403 @saniplastic
                                            last edited by

                                            @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                            @Obsolesce said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                            @saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

                                            1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.

                                            Just an FYI: it's not a backup when it's the only data. If you back up your VMs, then delete the originals, you no longer have a backup. All you have then is original data with no backup! Proceed wisely.

                                            you right

                                            i should have 2 series of backup.
                                            thanks

                                            He's saying you need to backup the metadata also.

                                            S 1 Reply Last reply Reply Quote 0
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