jj_uk

Hardware Requirements and UnRaid Capabilities

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I'm looking to move from FreeNAS to UnRaid because my FreeNAS server is full and you can't just add another drive with zfs; I'd need to replace each drive, one by one with larger disks. The Server is running 6x 3T disks in RAID-Z2, giving 13T usable space. Replacing all disks is expensive and wasteful as i'd have no use for the old disks.

 

I've never really 'clicked' with FreeNAS as it's just a bit above my paygrade, but here is what i'm using it for:

Jails:

- VPN Gateway (that other jails use to access the internet via OpenVPN)

- Plex Media Server + a few other jails running various stuff

- File server to a few windows PCs. Each user has there own storage area, the cannot access each-others storage (permissions), there is also a shared storage area that some, not all, users can access.

 

I'll be changing the hardware too, my new hardware is:

 

2x Intel Xeon 2640 v3  with Intel VT-x/VT-d and AES instructions

Asus z10pa-d8 motherboard

64G EEC ram

A case that can hold up to 20 disks.

 

Questions:

 

The hardware requirements page on the Lime-tech website doesn't actually give full hardware requirements for an UnRaid server. Its missing number of disks and what type of RAID cards are required.

It states only 1G of RAM is required (really?). The wiki gives approximate RAM required for VM, Dockers etc, but i'm interested in the amount of RAM that will be required per 1T disk, if there is even such a requirement, like there is in FreeNAS.

FreeNAS requires 8G RAM + 1G per 1T of storage. How much RAM does UnRaid need, per 1T of storage?

 

Do I need to use raid controller cards that have direct access to the disks e.g. a IBM M1015 card flashed to IT mode to allow UnRaid direct access to the HDDs, like I do if I were going to use FreeNAS on the new server, or can I use the on-board SATA ports that are controlled by the Intel C612 chipset (10 x SATA3 6Gb/s), or both the M1015 and the on-board SATA ports ?

 

As far as I can see, the only reference to number of disks that can be used is on the pricing page. It states that up to 28 data disks can be protected by 2 parity disks. Is this really enough parity to allow 2 disks to fail at the same time?

How many disks can be fully protected with only one parity disk?

 

Is it possible to have 2 USB (boot) drives, mirrored? In my FreeNAS box, the USB keys tend to die after 12-18 months (Kingston drives).

 

Can UnRaid monitor the SMART stats from the HDDs and send me an email if a disk is showing signs that it may fail, or if the drives' temperature exceeds a preset value, set by me?

 

Does UnRaid have Cron? So I can run my own scripts every so often? I use these mainly to schedule backups to other servers and to check that the jails (docker in UnRaid) are all running correctly, etc.

 

Can I install windows in a Virtual Desktop, then allow users to log in to and use windows, remotely, over a network?

I guess i'll need some hardware device to allow a keyboard, mouse and monitor to be linked over Ethernet to the UnRaid box - can anyone recommend a product that deals with this?

Does my server need a Graphics card for this, or is the graphics card built into the network box that the remote keyboard/mouse/monitor connects to?

 

I'd like all my drives to be encrypted. Is this supported, and will it degrade performance?

 

My server will be headless after the initial setup. Does UnRaid allow SSH to do maintenance, or is it WebGUI only?

 

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Replacing all disks is expensive and wasteful as i'd have no use for the old disks.

Does this mean you plan to add disks every time you need more space? Personally, I'm done adding disks. When I need more space, I'll replace my smallest or oldest disk with the largest I can afford at the time. I sell my old disks after I wipe them.

 

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The hardware requirements page on the Lime-tech website doesn't actually give full hardware requirements for an UnRaid server. Its missing number of disks and what type of RAID cards are required.

None. My test box was a desktop with a celeron & 2gig of RAM. You can see my current setup in my sig. It's very flexible. Minimal hardware will work. You don't need raid cards because there is no raid.

 

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It states only 1G of RAM is required (really?). The wiki gives approximate RAM required for VM, Dockers etc, but i'm interested in the amount of RAM that will be required per 1T disk, if there is even such a requirement, like there is in FreeNAS.

FreeNAS requires 8G RAM + 1G per 1T of storage. How much RAM does UnRaid need, per 1T of storage?

 

 

None. Does not apply. See my setup. Look through the various signatures on the forums and check out the setups.

 

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It states that up to 28 data disks can be protected by 2 parity disks. Is this really enough parity to allow 2 disks to fail at the same time?

 

 Yes.

 

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How many disks can be fully protected with only one parity disk?

That's the wrong question. How many disk failures can you have simultaneously and still recover your data? 1.

Just to clarify.  Utilizing the parity disks is how you upgrade disks.  When I need more storage space, I remove a disk and replace it with a new one. I then use the normal recovery process to recover the data on the disk I just replaced.

 

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 In my FreeNAS box, the USB keys tend to die after 12-18 months (Kingston drives).

My current keys are over 3 years old. I do acquire and prep them in pairs. If one fails, I simply reboot with the 2nd (in theory, that hasn't happened yet).

 

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Can UnRaid monitor the SMART stats from the HDDs and send me an email if a disk is showing signs that it may fail, or if the drives' temperature exceeds a preset value, set by me?

Yes.

 

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Does UnRaid have Cron?

Yes.

 

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Does UnRaid allow SSH to do maintenance, or is it WebGUI only?

Yes, it does allow SSH. It also has a webgui.

Can't comment on VM's as I don't run any.

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The system doesn't need any boot disk because it boots from a USB thumb drive.

So the number of disks is what number of disks you need for your storage needs.

The license selected decides max number of drives.

 

Max one array - with zero, one or two parity drives.

Then additional drives either in a cache pool or as stand-alone disks.

 

No RAID card - all parity operations are done in software. And compared to RAID, there is no striping. So you don't get the advantage of additional bandwidth from a multi-disk stripe. But instead you don't need to spin up all disks in the array to access specific files. If a movie is stored on a specific data disk, then it's enough that that drive is spinning to view the movie.

 

Next thing - since the data isn't striped, you don't lose all data if you lose more disks than what is covered by the number of parity drives. Each individual data disk can be pulled from unRAID and read stand-alone by a standard Linux installation.

 

No huge amount of RAM for the array, since unRAID doesn't have the deduplication logic of ZFS. So 2-4 GB is a good figure for the NAS functionality. Then additional RAM for running docker or VM.

 

You can't mirror the USB boot drive. But there is very little information written on it so lots of people have been using their drives for 5-10 years without needing to replace it. And if it breaks then you can copy the data to a different drive and then ask for a license transfer. I think it's one free transfer/year. If you break more than one drive the same year, then LT will most probably help you out anyway - I haven't heard about anyone who haven't been helped.

 

You can mix and match between motherboard SATA ports and supported HBA. But avoid Marvell-based controllers.

 

unRAID does look at SMART data and it's highly recommended that you configure mail notifications.

 

You can use own scripts.

 

If you install Windows in a virtual machine, then the recommendation is that you let the VM own a USB hub. Then you don't get issues with USB interrupts having to be translated between host machine and VM - the VM will handle the USB hub natively. You only need a dedicated graphics card for the VM if you want to connect a monitor to the VM.

 

You can use LUKS encryption for the disks. The degradation is very small when using a reasonably modern processor.

 

You normally use the web interface for management, but you can also connect using SSH.

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Thanks for your replies. Where do plugins come from? I cant find a link to plugins from the lime-tech homepage?

 

With regards to SATA ports and RAID cards; If using the on-board SATA ports, there will be a raid controller between UnRaid and the physical disk. The motherboard raid controller will be in RAID-0 (single disk) mode.

Does this not pose a problem to UnRaid as I believe the raid controller will write config info to the disk, preventing it from being placed in a different machine if the motherboard dies?

 

the 2nd paragraph of the 1st post here explains it: https://forums.freenas.org/index.php?threads/confused-about-that-lsi-card-join-the-crowd.11901/

Of-course this link is referring to ZFS, but surely this will remain true for UnRaid also?

 

On-board raid controllers can also, in some cases, cache data, meaning that it's not really written to the disk when the OS thinks it has been. A power failure when the data is cache'd by the raid controller would cause data loss.

 

So can UnRaid manage disks that are connected to a HBA controller? and is a HBA controller, for the reasons above, required? How does UnRaid ensure that the data has been written to the disk if using an on-board SATA port that has a raid controller between the disk and the port (or a SATA raid expansion card) ?

 

 

 

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unRAID (generally) requires JBOD.  Motherboard ports can be used, just don't set any RAID setting if the motherboard supports it.  If you need to support more disks than the motherboard can support, an LSI based HBA (flashed to IT mode depending on the model) is recommended.  Examples are the LSI-9201-8i, IBM M1015, and Dell PERC H310.

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43 minutes ago, jj_uk said:

So can UnRaid manage disks that are connected to a HBA controller? and is a HBA controller, for the reasons above, required? How does UnRaid ensure that the data has been written to the disk if using an on-board SATA port that has a raid controller between the disk and the port (or a SATA raid expansion card) ?

 

unRAID wants raw access to the individual disks - so standard HBA access. In some situations, it's possible to use a RAID controller and configure single-disk RAID volumes - but that's not something you want to do since you might get issues if you need to replace broken hardware. You really want each HDD to contain just a standard partition table + partition, and with the partition started on the expected disk offset.

 

unRAID doesn't stripe. So unRAID will flush data for the individual disks (which have their own file systems - and the different data disks can use different file systems) similar to how Linux flushes data to normal stand-alone disks. If you get an unclean shutdown, then unRAID will detect this on next boot and require a parity scan. A correcting parity scan will recompute any incorrect parity blocks. A non-correcting scan will instead just inform you about discrepancies between parity and data.

 

The file system of each of the data disks is responsible for whatever recovery that is needed in case of an unclean shutdown.

 

The above also means that after an unclean shutdown, in case you get a file system problem with one of the data disks you can run file system repair tools on individual data disks. But the device name used when repairing must be the device name used by the array to make sure that any file system repair will also recompute parity.

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guys- you've all be very helpful. I'll continue building the new server and get the trial going! (I'm 99% sure this is the product for me!)

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Posted (edited)
On 5/14/2018 at 2:32 PM, pwm said:

unRAID wants raw access to the individual disks - so standard HBA access. In some situations, it's possible to use a RAID controller and configure single-disk RAID volumes - but that's not something you want to do since you might get issues if you need to replace broken hardware. You really want each HDD to contain just a standard partition table + partition, and with the partition started on the expected disk offset.

Following up on this, if the drives are connected to the on-board SATA ports on the motherboard, this means that the motherboards' RAID controller is between unRAID and the physical drive. In my case, that's an on-board Intel C612 RAID controller. 

Therefore, unRAID *doesn't* have HBA access to the disks; it has RAID 0 single disk mode access to the disk. 

 

Am I missing something?

For the above reasons, would on-board SATA ports just be a bad idea?

We'd need to use PCIe cards (such as the LSI/IBM M1050 flashed to SAS9211 IT mode) in order to allow unRAID direct access the disks (?)

 

Edited by jj_uk

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You want unRAID to access each disk individually, which is not possible with a RAID controller in RAID0 mode. Unless you can set the controller to JBOD mode, it is better to connect the disks on a HBA controller.

 

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Yes, exactly. So are unRAID users using the on-board SATA ports when they shouldn't be?  If they are, are they risking their data?

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1 hour ago, jj_uk said:

C612 RAID controller. 

That's not a RAID controller, it's fakeraid, it's perfectly fine for unRAID, just make sure it's in AHCI mode.

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Posted (edited)
6 hours ago, jj_uk said:

Yes, exactly. So are unRAID users using the on-board SATA ports when they shouldn't be?  If they are, are they risking their data? 

 

I have two servers (see sig), in both cases all disks are connected to motherboard SATA ports in AHCI mode.  The only instance in which you should avoid onboard SATA ports is if they are controlled by a Marvell controller. 

 

Many unRAID users with smaller disk counts are running systems with nothing but onboard-SATA-connected disks.  Personally, I prefer fewer larger disks (8TB is my minimum) to more smaller disks.  In fact, when I decided to go to larger disks in my main server, I repurposed most of the smaller 3TB disks in a backup server.  Other disks I wiped and sold or used in unRAID builds for friends who needed far less storage.

 

There is no more risk of data loss on drives attached to the motherboard SATA ports than there is on disks attached to an HBA and, in fact, some would say the greater risk lies with HBA-attached disks.  The truth is that many other factors other than to which SATA port a disk is connected (unless the port/cable/controller fails) are more likely to contribute to data integrity issues.

Edited by Hoopster

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