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I've got a dual Xeon X5650 (6core) HP ProLiant DL160 G6 with 72G RAM and an HP P410 4port hardware raid card that I want to repurpose as a NAS and a test server. Additionally, I have 4 x 4T drives in it.

My initial plan was to just HW RAID5 the 4 drives and install Citrix Xenserver 7.2 (free version) on it. I have a couple of Windows VMs that I nede to run, as well as a PFSense firewall. But the primary use would be to create a main VM to run Docker (CoreOS or CentOS or Ubuntu), and a large 8T Virtual Drive assigned to that VM. Then run different Docker images mounted to different volumes created within that large VHD.

Some of the docker images I would like to run:

  • Plex
  • Sonarr
  • Gitlab
  • Docker-timemachine
  • nextCloud
  • ...

Part of the 8T virtual drive would also be exposed as a NAS for sharing space in the office (this is for a small business context).

So now, I'm wondering if my approach is sound at all; should I be putting this much faith in hardware raid vs just using ZFS across the 4 drives instead (and dropping the HW RAID altogether)?

One concern I have of the HW RAID is if the controller fails. Then I end up have 12T of data that can only be recovered by another P410 controller (and I don't have a hot spare).

On the other hand, I am having difficulty finding docs if/how to install Citrix Xenserver on ZFS. Everything I've found seems to discuss ZFS as a Storage Repo for XS, but nothing relating to install DOM0 as a ZFS install. Secondly, I do have concerns of any ZFS management / maintenance required through DOM0. Normally, I like to have DOM0 run as much stock as possible - this simplifies upgrades.

Is installing Citrix XenServer on a ZFS even feasible? ie: the Dom0 would be installed and running on a 12T ZFS. Given that XenServer is based on CentOS7, I figure it should be doable, but not sure how. But even if it is feasible, is it recommended?

Is running XenServer on ZFS (if doable) a safe and recomended alternative to running a HW Raid5 (with FBWC)?

Eric B.
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  • You ask a lot of questions which makes this too broad. Some of the questions almost certainly be answered by reading the Citrix documentation. Home use is not topical here. – user9517 Jan 07 '18 at 06:18
  • HW RAID and ZFS are pretty much two separate issues: there's no reason why you can't use ZFS on top of hardware RAID. It may be technically redundant but if you need ZFS for FreeNAS it won't hurt. However, I have to agree, you need to structure your question in a more direct way. – Simon Greenwood Jan 07 '18 at 11:26
  • Apologies for the poorly structured rambling; I wrote it when I was too tired. I tried to reformat the question more directly, with a little background info and a direct question – Eric B. Jan 07 '18 at 17:10
  • @user449299 It isn't home use - that was a late night typo. It is for a small business context. And I couldn't find anything about running Dom0 in a ZFS context in the Citrix docs. Have you already seen a chapter or whitepaper on that? – Eric B. Jan 07 '18 at 17:11
  • @SimonGreenwood Running something like ZFS on a VHD would likely have poor end results. It wouldn't be able to properly snapshot or ensure proper cache flushes/etc. Although it would technically works, I can't see it being a safe implementation. Something like ZFS was designed to work with direct writes to the hardware, and not through a vitrual layer. – Eric B. Jan 07 '18 at 17:12
  • Yeah sure ... I choose not to believe you and therefore not to supply my tome to help you. – user9517 Jan 07 '18 at 17:13
  • @EricB. I'm inclined to agree in that context, you would present virtual storage directly on the RAID device. – Simon Greenwood Jan 07 '18 at 17:27
  • @SimonGreenwood I'm not sure I understand your comment. But my takeaway from your comment is to skip ZFS then and just stay with HW RAID. But the question remains is that is "safe" decision without having a backup P410 available. – Eric B. Jan 07 '18 at 17:48

2 Answers2

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This is overly complicated. If it's a production environment, skip all of this. If it's a home science project, still skip it. It sounds like you have a technical solution looking for a problem.

Let's break this down: You're concerned about hardware RAID on an HP SmartArray P410 RAID controller. The use of a P410 means that you're using HP server hardware. HP, a company who has tremendous mindshare and large install bases throughout the industry.

The P410 controller is fine. They don't fail often... and even if one did, have a plan to purchase or repair. You don't worry about CPU failure; motherboard failure or disk backplane failure, do you? Those are relatively infrequent, so deal with it as it comes.

ZFS is a non-starter for this solution. It won't add anything, especially when complicated by whatever's needed to run XenServer. It would be a different story if you were using a KVM hypervisor or VMware, though.

I think the lack of information about the solution you're trying to build is a sign that it's not a recommended or common approach to solving the problem.

ewwhite
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  • Thanks for the voice of reason. I guess I just needed that reassurance.. The reason I don't worry about a dead CPU or mb failure is b/c if it is just a JBOD, then I can retrieve the data off any other machine. If the P410 fails, then I need another P410 or my data is gone. RAID or not, I don't think there is any way to recover data if I don't have the HW controller. That being said, I've looked at replacement costs, and they are fairly inexpensive today; I might just go out and buy another one as a backup. I've already got a matched DL160 (slower CPU) as a cold spare if needed. – Eric B. Jan 07 '18 at 21:09
  • I've never had an HP Smart Array P410 controller fail. Standalone or embedded on motherboard. – ewwhite Jan 07 '18 at 21:11
  • G6 is pretty old at this point. They'll surely start having parts fail soon... – Michael Hampton Jan 07 '18 at 21:24
  • You can also recover data from disks that were behind a p410 array using only software. – Spooler Jan 07 '18 at 21:48
  • @MichaelHampton Other components may fail. The system board, PSUs, etc. But the RAID controller has a low failure rate. I've seen this at scale. The premise of the question is flawed. – ewwhite Jan 07 '18 at 22:00
  • @SmallLoanOf1M Really? I didn't know that was possible. Do you know of any documentation that outlines the procedure to recover via SW? – Eric B. Jan 08 '18 at 01:16
  • @EricB. Don't go down that rabbit hole. – ewwhite Jan 08 '18 at 03:27
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If your requirement is "free virtualisation that supports ZFS" (perhaps for testing/learning purposes) then you could look at Proxmox Virtual Environment instead of Xenserver. We use it in production with ZFS for both the root filesystem and the VM storage pool.

Some of our VM hosts have HP SmartArray P440 cards because they were re-purposed from other things. We've found the most reliable way to use these is to create a bunch of RAID 0 volumes on the individual disks and just pass those through to ZFS.

hillsy
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