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Odom

New to unRaid, lot's of questions

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Hi,

 

I'm very new to unRaid, only recently having heard of it, but I am already really interested in it. I had Qnap NAS devices for a long time but was now considering building my own NAS, and so far what I read about unRaid it looks to be really amazing. This past week I have been reading a lot about it (here in the forums, the FAQ, Reddit, other videos and articles), but I still have a lot of questions about it, especially also to the hardware required (as in will this work, or what is this).

 

Is this the right forum (Pre-Sales) to post these questions, or should I put all the hardware questions in the relevant sub-sections?

 

I do have a first question about the licensing. If I purchase the Plus version, can I later upgrade to the Pro edition, using the same USB stick and setup that I have?

 

Many thanks!!

 

Odom

 

 

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6 minutes ago, Odom said:

Is this the right forum (Pre-Sales) to post these questions

This is fine. Go ahead and post your other questions to this same thread.

 

7 minutes ago, Odom said:

If I purchase the Plus version, can I later upgrade to the Pro edition, using the same USB stick and setup that I have?

Yes

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Hi,

 

many thanks, so here goes :)

 

As I understand, you can mix and match all kinds of hard drives and the parity works differently from the traditional RAID.

  1. If I have 5 drives, of which one is the parity, how is the data spread across them? Say for example, 5x 2TB, 8TB usable, if I copy 4TB of data over, how is it spread out over the drives? Is it evenly spread out (one file here, another there) or does it first fill one drive, then the next?
  2. What exactly does the cache drive do? I mean, I know what cache is for, but if I mainly use unRaid for storage for movies and series (many single big files), how does cache improve anything, if it isn't the same size of my total storage? After watching a movie I understand it would be cached, but I'm not watching it again, so I see no advantage there.
  3. When transferring data from my Qnap over to unRaid, will it put that data on the cache, which will then in time offload it to the storage array? What would be a recommended size for a cache drive?
  4. I've read a lot in this forum and Reddit that when docker apps, VM's and some other config files are held on the cache. Doesn't this cause a lot of writes and weares out the consumer cache drives?

 

I plan on using unRaid mainly for storage, but also to run the occasional VM every now and then for testing scenarios. I read in the forums that people put their VM's on the cache SSD. Would it be possible to get an additional SSD and keep all VM's on it? Even if I don't have this particular SSD in the main storage array?

 

When having 20TB - 50TB of storage and more, does it make more sense to keep one big array or smaller ones? Is there an advantage/disadvantage in having 2x 20TB arrays or simply one big 40TB array?

 

Regarding the hard drives:

  1. Is there a limit to the amount of hard drives you can have with unRaid?
  2. Seeing as this is not exactly like traditional RAID, is there an advantage in using NAS designed drives? For example the WD Red, will the NAS features of these drives be taken advantage of by unRaid?
  3. If not the above, does it then matter what drives I use, for example as long as they are all 7200RPM?
  4. If I mix up all kind of drives, how is the performance impacted? Say I have 5400RPM and 7200RPM drives and I copy 5TB of data to the array. If the files are spread over the drives, am I correct to assume that on the 7200RPM drives the process would be faster, only to then slow down when copying to the 5400RPM?

 

And regarding storage in general, here I lack the technical knowledge a bit. If I want to have more drives than my motherboard allows, I read that there are these HBA cards, risers, expanders. I'm not sure I understand how these work.

  1. I understand an HBA card to be some kind of an expansion card. Looking up some online you can have from 64 to 256 extra drives attached to it. They usually mention SAS drives, but from reading this forum you can also use standard SATA drives. Most HBA cards I googled in thi forum only have 2 ports and people use a cable that fits that port and on the other end has 8 device connectors. How do you get to use (connect) the remaining 56 cards?
  2. Does everybody buy them cheap on eBay? When I look up the prices these cards are often 200€ and upwards.
  3. I read a lot here and there about flashing these HBA cards to IT Mode and found plenty of guides how to do it, but why exactly do you do this? What does it mean to flash to IT Mode?
  4. Does anything speak against using a combination of the SATA ports from the motherboard plus the ones from an HBA when you run out of ports on the motherboard? Or is it recommended to rather run all storage devices from an HBA?

 

I have an older Coolermaster case and a PSU at home, so I was planning on getting a motherboard, CPU, Cooler & Ram to complete the setup. Considering price/value, I was considering a Ryzen 5 2600 setup. I never build anything with AMD, always had Intel, due to at the time of building my rigs they were the best for gaming, but this being purely for storage and running the occasional VM and docker, the Ryzen5 and Mobo would be around 200€ combination.

  1. I saw a few threads about issues between unRaid and AMD Ryzen setups, but these threads were a year old. Would a combination like this work well?
  2. I haven't build a PC in a while so I'm pretty out of CPU/motherboard and RAM speeds. Would a Ryzen 5 2600 work well with a Gigabyte B450 AORUS M motherboard? (https://www.alternate.de/PC/PC-Konfigurator#!/product/0/43/1471765, I used a PC configurator to help find a compatible motherboard, as I never build an AMD rig).
  3. I read that some people have ECC RAM, what is the advantage of that in conjunction with unRaid? Can you only use ECC RAM when you have a Xeon CPU?
  4. If I get the CPU and mobo from point 2, and 16GB or 32GB RAM, what speeds should I get? The CPU shows as going up to DDR4-2933, so does the Mobo. Would that be OK? I also read in a thread somewhere that overclocked RAM caused problems, if I remember correctly in that thread the mobo overcklocked it automatically, however this could be turned off.
  5. And as a follow-up to point 4, is it better to get 2 or 4 sticks and fill all the slots? I understand that having only 2 slots filled allows for easier expansion at a later point in time, but does DDR4 require all 4 slots to be filled?

 

I think this is it fow now, sorry for the barrage of questions, but I appreciate any answers anyone could provide. Once I have the last 3 missing components I'm definitely getting a trial version of unRaid, hoping to upgrade it to the full version afterwards, with the ultimate goal replacing my Qnap NAS.

 

Thanks very much!!

Odom

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I'll answer some of your questions:

52 minutes ago, Odom said:

I understand an HBA card to be some kind of an expansion card. Looking up some online you can have from 64 to 256 extra drives attached to it. They usually mention SAS drives, but from reading this forum you can also use standard SATA drives. Most HBA cards I googled in thi forum only have 2 ports and people use a cable that fits that port and on the other end has 8 device connectors. How do you get to use (connect) the remaining 56 cards? 

Most common HBAs have 8 ports, though there are also models with 4,16,24,etc, you can use one or more SAS expanders to use more drives (SAS and/or SATA) with one HBA, expanders are usually 24 to 32 ports.

 

55 minutes ago, Odom said:

Does everybody buy them cheap on eBay? When I look up the prices these cards are often 200€ and upwards.

Yes, you can find some of the recommended LSI HBAS starting at around $40/50.

 

55 minutes ago, Odom said:

read a lot here and there about flashing these HBA cards to IT Mode and found plenty of guides how to do it, but why exactly do you do this? What does it mean to flash to IT Mode?

You only need to do this if you get a RAID controller, that supports IT mode, since IT mode is recommended for Unraid, if you get a plain HBA no need to do any flashing.

 

57 minutes ago, Odom said:

Does anything speak against using a combination of the SATA ports from the motherboard plus the ones from an HBA when you run out of ports on the motherboard? Or is it recommended to rather run all storage devices from an HBA?

No problem whatsoever of using the onboard ports together with one or more HBAs.

 

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35 minutes ago, Odom said:

If I have 5 drives, of which one is the parity, how is the data spread across them? Say for example, 5x 2TB, 8TB usable, if I copy 4TB of data over, how is it spread out over the drives? Is it evenly spread out (one file here, another there) or does it first fill one drive, then the next? 

Their is a setting available for each share that says which disks should be used and one (called Allocation Method) determines how theavailable   disk should be used.  One thing to remember is that any particular file is always on a particular disk.

 

38 minutes ago, Odom said:

What exactly does the cache drive do? I mean, I know what cache is for, but if I mainly use unRaid for storage for movies and series (many single big files), how does cache improve anything, if it isn't the same size of my total storage? After watching a movie I understand it would be cached, but I'm not watching it again, so I see no advantage there.

Writing directly to the array is comparatively slow as it actually involves 4 I/O operations (a read of the data disk and corresponding sector on the parity disk; a disk rotation; and then writes of a sector back to both the data drive and the parity drive).   Reads run much faster as they simply access the relevant data drive.

 

If you have a cache drive then (assuming you have enabled using it for the share in question) then New files are written instead to the cache drive (which involves a single I/O operation and later (typically scheduled for overnight) moved to the array.  As this move happens outside normal hours of use the End User does not get affected by the slow right speed to array disks.   In this mode the cache disk is therefore used to speed up writes to the array.

 

The cache disk can also be used to hold files where performance is more critical (e.g. VMs, docker containers) and thus where you do not want the write overheads involved on array drives)

44 minutes ago, Odom said:

When transferring data from my Qnap over to unRaid, will it put that data on the cache, which will then in time offload it to the storage array? What would be a recommended size for a cache drive?

It depends on whether you have the share configured for using the cache or not.   Many people do not bother for their main media shares accepting the slower write speed.

 

Also, when you are doing the initial data load it is frequently recommended that you start without a parity disk assigned as then the writes are a single I/O operation and thus much faster.    You can then build parity at a later stage.    However until parity is built your data on the array is not protected.

 

47 minutes ago, Odom said:

I've read a lot in this forum and Reddit that when docker apps, VM's and some other config files are held on the cache. Doesn't this cause a lot of writes and weares out the consumer cache drives?

This data has to go somewhere!

 

Typically the cache drive(s) is a SSD to give performance benefits over HDD although this is not mandated.

 

54 minutes ago, Odom said:

Is there a limit to the amount of hard drives you can have with unRaid?

yes.  The details are under the License description.   The top end (Pro license) can have a maximum of 28 data drives in the array and (optionally) one or two parity drives.   You can also have up to 30 drives in a cache pool although most people would only have a small numer (often only one).

 

56 minutes ago, Odom said:

Seeing as this is not exactly like traditional RAID, is there an advantage in using NAS designed drives? For example the WD Red, will the NAS features of these drives be taken advantage of by unRaid? 

This is one of those debatable points.   Unraid does not treat such drives any differently.  They  often come with a longer warranty period so the decision is up to the end-user.   Many people do not bother.

 

57 minutes ago, Odom said:

If not the above, does it then matter what drives I use, for example as long as they are all 7200RPM?

You can buy any drives you like.   Performance of any particular I/O is determined by the slowest of the drives involved.  This means it normally makes sense for the parity drives to not be your slowest drives

 

59 minutes ago, Odom said:

If I mix up all kind of drives, how is the performance impacted? Say I have 5400RPM and 7200RPM drives and I copy 5TB of data to the array. If the files are spread over the drives, am I correct to assume that on the 7200RPM drives the process would be faster, only to then slow down when copying to the 5400RPM?

Yes.   Note however the comment about the parity drive also needing to be taken into account.

 

49 minutes ago, Odom said:

I understand an HBA card to be some kind of an expansion card. Looking up some online you can have from 64 to 256 extra drives attached to it. They usually mention SAS drives, but from reading this forum you can also use standard SATA drives. Most HBA cards I googled in thi forum only have 2 ports and people use a cable that fits that port and on the other end has 8 device connectors. How do you get to use (connect) the remaining 56 cards?

Ideally you want a HBA card that does NOT have RAID support as this can interfere with Unraid.   The HBA cards recommended for use with Unraid are those based on LSI chipsets.  These provide support for a maximum of 16 drives per card., with most people using SATA drives rather than SAS drives.

 

Not sure what cards you were looking at that supported such a large number of drives, but whatever they were they are not the sort that would be used with an Unraid system.    Remember that Unraid has a limit of 28 data drives (plus up to 2 parity drives) plus whatever drives you have in the cache so such huge limits are not appropriate.

 

1 hour ago, Odom said:

Does everybody buy them cheap on eBay? When I look up the prices these cards are often 200€ and upwards.

It is up to the end user.    Having said that it is often recommended to go for Used cards being recycled from discontinued servers from eBay as there is a significant number of 'fakes' on eBay when buying direct.

 

1 hour ago, Odom said:

I read a lot here and there about flashing these HBA cards to IT Mode and found plenty of guides how to do it, but why exactly do you do this? What does it mean to flash to IT Mode?

IT mode means that you have disabled any RAID capability on the cards.   This is optimal for Unraid to make best use of the cards with Unraid as cards with built-in RAID support often 'mask' some of the disk attributes and thus interfere with Unraid's capability to manage the attached disks in an optimal fashion.

 

1 hour ago, Odom said:

Does anything speak against using a combination of the SATA ports from the motherboard plus the ones from an HBA when you run out of ports on the motherboard? Or is it recommended to rather run all storage devices from an HBA?

This is perfectly normal use.   Most people only add HBA card when they need more ports than their motherboard supplies.  Some points to note.

  • Avoid using ports based on a Marvel chipset (either on motherboard or on an HBA).   Marvel chipsets do not work well with recent Linux releases and have a tendency to let disk drop offline unexpectedly for no apparent reason.
  • It is often best to attach any SSDs to motherboard ports as not all HBA cards support Trim operations for keeping SSDs operating optimally.
  • Avoid using Port Multipliers if at all possible.  Though they work they tend to impact both performance and reliability.

 

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Looks like many of your questions have been answered. There is Help in the webUI for many things. I will just give you some links for further study. Also be sure to check the other "stickies" pinned near the top of many subforums.

 

https://forums.unraid.net/topic/52998-guides-and-videos/

https://wiki.unraid.net/UnRAID_6/Overview

https://forums.unraid.net/topic/37579-need-help-read-me-first/

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?page=2&tab=comments#comment-554741

https://forums.unraid.net/topic/57181-real-docker-faq/

 

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wow  Thank you all very much for all the answers!!!

 

Now I just need to figure out what Motherboard and RAM to get, then I can start building the rig and giving unRaid a go.

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I remembered one more question regarding the licence. If I get unRaid now, does that entitle me only to v6.x or also any future versions, like v7.x and so?

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21 minutes ago, Odom said:

I remembered one more question regarding the licence. If I get unRaid now, does that entitle me only to v6.x or also any future versions, like v7.x and so?

The licensing terms on the Unraid site say that a license purchased today is valid for all future versions.   That is also how it operated in the past as well.     As to whether that always apply to new licenses I have no idea.

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