FreeNAS versus unRAID as the operating-system for a DIY NAS?

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BLKMGK Offline
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Post: #31
A standard RAID can lose a disk and not lose data. However losing TWO disks often means losing ALL data unless you've added still more disks to the array for redundancy. Likewise a standard RAID spans files across many disks - the advantage being FAST data access as you get data from multiple disks at once. However this means they all must spin to get access to the data. unRAID doesn't span disks like that and stores parity on a dedicated drive with other drives using REISERfs which is a standard F/S. Downside being that the array doesn't appear as a giant volume (shares take care of this) and that it's not as fast. However for spitting out even the highest def video you do NOT need uber fast transfer rates so this is good. unRAID is NOT meant for enterprise storage, it's meant for home media primarily and it serves this purpose VERY well.

ZFS I cannot speak to. I have researched it some because it's always something put forth as a solution but I'm not sure how you would set this up booting from a USB stick etc. and I think Solaris x86 and BSD (?) are the only ones with real support. Solaris is a bit shaky so far as corporate support right now I think and i'm not sure how friendly BSD is. unRAID however is pretty simple I think and lots of folks are on the suport forum willing to help...

Openelec Gotham, MCE remote(s), Intel i3 NUC, DVDs fed from unRAID cataloged by DVD Profiler. HD-DVD encoded with Handbrake to x.264. Yamaha receiver(s)
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BLKMGK Offline
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Post: #32
Heh, shoudl have refreshed before responding. Pike makes a good point - the new EARS drives require a jumper or some other means to be properly supported. The WD and Seagate models do this fine - I'm running at least one of them now.

Froggit - does ZFS require all disks spinning in order to make a write or read? If so I would argue that this is a downside since that means more energy used. Likewise if it needs 2 disks for parity to recover data on a dual failure that's not good. I'm wiling to lose data on a dual failure - 2 disks worth - but NOT an entire array of say 16 drives. ZFS sounds attractive for many things from what I have read but I have not yet heard anything compelling over unRAID. Especially if it also requires an OS disk rather than booting from USB and giving me as much storage as possible. I can run from 2-16 disks in my array and never lose more than a single disk to parity overhead and nothing to OS overhead...

Openelec Gotham, MCE remote(s), Intel i3 NUC, DVDs fed from unRAID cataloged by DVD Profiler. HD-DVD encoded with Handbrake to x.264. Yamaha receiver(s)
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PANiCnz Offline
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Post: #33
PatrickVogeli Wrote:Does FreeNAS need a RAID capable BIOS or a hardware raid controller? Does it allow you to add HDDs as you need them?Does it allow you to add HDDs as you need them? Does it allow to use mixed capacity drives? How does FreeNAS behave in case 2 HDDs fail?


If your talking about FreeNAS you will need to be more specific, software raid5, zfs or simply just sharing individual disk with samba? You appear to be confusing ZFS with FreeNAS they're very different, FreeNAS is an OS while ZFS is a combined file system and logical volume manager.

If all the unRAID fan boys actually did some research they would be amazed by ZFS, sadly their arguments are always the same.

ZFS is a pretty complicated beasty and requires a decent understanding but its well worth it.
(This post was last modified: 2010-10-12 11:09 by PANiCnz.)
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PatrickVogeli Offline
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Post: #34
Well, I just wanted to if freenas will do those things...

I know unraid will allow you to add HDDs as you need more space and you can mix different type of driver. If a drive fails, I can recover it and lose no data. If 2 drive fail, I loose their data but not all data in the array. unRaid doesn't need any raid system, it's all done in software in the unRaid OS: no raid in bios, no extra hardware raid system.

It's pretty simple: will freeNAS do that? I don't mind what's going under the hood, I'd just like to know if freeNAS does that or if it does better.

Hope it's a bit better explained now.
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sWORDs Offline
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Post: #35
Freenas can when you use ZFS. No "HW" raid needed. (The BIOS raid is software aswell, just in the BIOS instead of OS)

I use two types of Freenas setups both getting up to 60% CPU usage:

1 RAID 6 HW RAID with low budget cpu (Adaptec 5805 with ION330)
2 ZFS with medium budget cpu (AMD Athlon II X2 235e)
(This post was last modified: 2010-10-12 11:49 by sWORDs.)
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darkscout Offline
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Post: #36
FreeNAS is getting a bit old. It's based on FreeBSD 7, which had ZFS listed as experimental. FreeNAS 8 is still in alpha.

A better replacement would be NexentaStor which is free up to 12GB.

Plus it uses the OpenSolaris kernel, which (IMHO) handles ZFS a bit better.
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froggit Offline
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Post: #37
teaguecl Wrote:I sort of disagree with you here. I don't backup anything on my NAS. If I get a double disk failure, my data is gone - and that's fine. The reason why is that I don't put anything valuable on it. You only need to backup valuable data - that which cannot be replaced. This is typically content you create, that is unique to you, including personal photos, documents, etc. Unless you are generating GB's of content (you are a filmmaker or similar) you don't need to backup your NAS. I have 20 GB of blu-ray and DVD rips on my NAS, and it would be a pain to re-rip them - but it would not be a disaster. I'm pretty sure if my home burned down I could find another copy of Ghostbusters. The videos of the kids and my masters thesis however, are irreplaceable - those really are backed up both locally and remotely.
I would suggest that an UNRAID or Drobo or RAIDZ is more than fine for 99% of the stuff you want to store on your NAS for use with a htpc. It gives you a little protection from disk failure - just enough to ease the pain of re-ripping, but certainly not enough to store really important data on.
By all means back up your important stuff - but don't bother with your DVD rips of Lord of the Rings.

Indeed, backups are vital for irreplaceable personally-produced data like docs, spreadsheets, source code, photos, films.

For replaceable data like DVDs etc, then like you say, you have the original DVD so you don't care about doing backups.

However, if one has a lot of DVDs, when considering the amount of time taken to re-rip them, and go through the identification process so that XBMC can scrape them correctly to provide library metadata, backups still make a lot of sense. But that decision is a personal one, I agree. Personally, I just created a clone of the NAS and then do incremental backups based on snapshots, which is pretty straightforward with ZFS.
(This post was last modified: 2010-10-12 15:24 by froggit.)
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TugboatBill Offline
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Post: #38
PANiCnz Wrote:ZFS is a pretty complicated beasty and requires a decent understanding but its well worth it.

Put that down as a disadvantage to ZFS then (unless you like to waste the hours away fiddling).
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darkscout Offline
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Post: #39
TugboatBill Wrote:Put that down as a disadvantage to ZFS then (unless you like to waste the hours away fiddling).

I'm really confused at what would take "hours away fiddling".

http://flux.org.uk/howto/solaris/zfs_tutorial_01
http://www.mattzone.com/site/index.php?n...icle&sid=3

zpool create tank mirror c2t0d0 c4t0d0
zfs create tank/Movies
zfs set sharesmb=on tank/Movies

You've just created a mirrored array, added a Movies 'drive', and shared it via SMB.

When I first started fiddling with it, I figured "It can't be this easy"... but it is.
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poofyhairguy Offline
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Post: #40
I would argue that Unraid gives less of a chance for data loss because you can mix and match different hard drive sizes and vendors over the course of months to grow your array, while ZFS requires you to have all the hard drives wanted in the array when you first build the system.

Unless you go out of your way to buy the same hard drives from different vendors, then you are basically gonna buy all your HDs from the same batch. If that batch was defective then there is a change you can EASILY lose more than two drives at a time and all your data is down the tubes. For an enterprise you buy enterprise drives to avoid that, but most of us are using consumer drives. That makes ZFS a liability.

With Unraid the only way more than one HD is going down at one time is if God hates you (aka PSU catches on fire) or you are stupid and you go against Tom's recommendation to mix and match different drives.

As a bonus Unraid lets you upgrade the array size, one drive at a time, without losing data. With ZFS/RAID you are having to basically build a new array to change hard drive sizes (and then buy all those bigger HDs all at once).

ZFS is a business solution. Unraid is a home media server solution.

The only reason to pick ZFS over Unraid is:

1. You want to play with ZFS
2. Your server is doing more than serving media in a capacity where write speeds matter (aka it doubles as a web server or something)
3. You have some sort of reservation for paying for Unraid

Mini/Micro ITX Frontend (with SSD) + Mediaserver/NAS + Logitech Harmony + LCD/LED/Plasma TV + Nice AV Receiver + XBMC + USENET + sabnzbd + sickbeard +couchpotato

My Setup--HTPC Building Guide- Start Here--Advice on Hard Drives and SSDs--Mediaserver Guide--Harmony Guide
(This post was last modified: 2010-10-12 22:45 by poofyhairguy.)
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froggit Offline
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Post: #41
BLKMGK Wrote:A standard RAID can lose a disk and not lose data. However losing TWO disks often means losing ALL data unless you've added still more disks to the array for redundancy.

I can't say for all RAID systems, but with ZFS you can choose your preferred level of redundancy. For example, if you're happy with the capacity of one disk for parity data then you could choose a simple 2-drive mirror, or RAID-Z1. If you want more safety then you can choose double-parity like RAID-Z2. If you want triple-parity then you can choose RAID-Z3, which allows three drives to fail before you lose any data.

So depending on your wallet / paranoia level, you can choose a level of data safety that suits your own situation.

BLKMGK Wrote:Likewise a standard RAID spans files across many disks - the advantage being FAST data access as you get data from multiple disks at once. However this means they all must spin to get access to the data. unRAID doesn't span disks like that and stores parity on a dedicated drive with other drives using REISERfs which is a standard F/S. Downside being that the array doesn't appear as a giant volume (shares take care of this) and that it's not as fast. However for spitting out even the highest def video you do NOT need uber fast transfer rates so this is good. unRAID is NOT meant for enterprise storage, it's meant for home media primarily and it serves this purpose VERY well.

Why not use enterprise-level data safety mechanisms that are *free* and available within ZFS? What happens with unRAID if your parity drive dies, or one or two of your data drives dies? With ZFS, using RAID-Z2, if *any* one or two drives die you lose no data, and you can rebuild any dead drives so *no* data is lost.

BLKMGK Wrote:ZFS I cannot speak to. I have researched it some because it's always something put forth as a solution but I'm not sure how you would set this up booting from a USB stick etc.

USB sticks are not generally suitable for booting OS's from as they tend to write frequently to the devices (logs etc), and this will reduce the life of the USB stick. They are also fairly slow to boot from.

BLKMGK Wrote:and I think Solaris x86 and BSD (?) are the only ones with real support. Solaris is a bit shaky so far as corporate support right now I think and i'm not sure how friendly BSD is. unRAID however is pretty simple I think and lots of folks are on the suport forum willing to help...

Solaris has corporate support from Oracle.

Also, for ZFS newbies there is a great forum available on the OpenSolaris.org site which is frequented by very knowledgeable & helpful ZFS users - see here, including Oracle staffers: http://opensolaris.org/jive/forum.jspa?forumID=80

ZFS is simple - here I will create a 6-drive array which can survive any two drives failing before any data is lost:
# zpool create tank RAID-Z2 drive1 drive2 drive3 drive4 drive5 drive6

Now we'll create a file system to store our movies in:
# zfs create tank/movies

Now we'll create a 'share' so that our movies can be shared to other devices like computers around the home, or HTPC / media center:
# zfs set sharesmb=on tank/movies

Voila, what's hard about that?

Now, for one of the killer features of ZFS, that virtually no other RAID system has -- the ability to find and repair all files that have become corrupt due to 'bit rot':
# zpool scrub tank

This last command will read the contents of *all* files within your storage system and compare each block with a 256-bit block checksum. Any blocks not matching the checksum will be recovered by using the parity data stored when the file was originally created. This feature is priceless and gives you peace of mind that your data is 100% correct as it should be. Can unRAID or FreeNAS do that?
(This post was last modified: 2010-10-12 23:02 by froggit.)
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froggit Offline
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Post: #42
BLKMGK Wrote:Froggit - does ZFS require all disks spinning in order to make a write or read?

Not if the data is in cache. ZFS uses available free memory to store files read.

However, it will need to spin the drives if data is not in cache.

BLKMGK Wrote:If so I would argue that this is a downside since that means more energy used.

However, for energy reduction, you may use the OS power management features to spin-down drives after a set time period like 5 minutes, and a lot of the 'green' drives auto-park heads for reduced power usage anyway.

BLKMGK Wrote:Likewise if it needs 2 disks for parity to recover data on a dual failure that's not good. I'm wiling to lose data on a dual failure - 2 disks worth - but NOT an entire array of say 16 drives.

You are very generous. I am not willing to lose any data. And the price of 2 drives to give peace of mind helps me sleep really well. And I have a backup of everything.

BLKMGK Wrote:ZFS sounds attractive for many things from what I have read but I have not yet heard anything compelling over unRAID. Especially if it also requires an OS disk rather than booting from USB and giving me as much storage as possible. I can run from 2-16 disks in my array and never lose more than a single disk to parity overhead and nothing to OS overhead...

Read my previous reply about ZFS to get an idea of how easy it is to use and setup, and the data safety mechanisms built in. You can look at parity data a bit like insurance: have no parity data and you lose data when drive(s) die, have parity data and your loss is zero to low, depending on how much parity data you have and how many drives die. It's not rocket science. Once this is understood well, one can plan the level of safety required.
(This post was last modified: 2010-10-12 23:37 by froggit.)
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froggit Offline
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Post: #43
poofyhairguy Wrote:I would argue that Unraid gives less of a chance for data loss because you can mix and match different hard drive sizes and vendors over the course of months to grow your array, while ZFS requires you to have all the hard drives wanted in the array when you first build the system.

That's not true. With ZFS you can add a 'vdev' to your existing pool. A vdev (virtual device) is a group of drives - like a 2-drive mirror, to a multi-drive RAID-Z3 array. It's up to you. What you are probably confused about is that you can't expand an existing vdev, although you can replace each drive with a larger one, so you can expand an existing vdev in terms of capacity but not expand the number of drives within an existing vdev.

poofyhairguy Wrote:Unless you go out of your way to buy the same hard drives from different vendors, then you are basically gonna buy all your HDs from the same batch. If that batch was defective then there is a change you can EASILY lose more than two drives at a time and all your data is down the tubes. For an enterprise you buy enterprise drives to avoid that, but most of us are using consumer drives. That makes ZFS a liability.

You can mix drives from different manufacturers if you want to with ZFS. Personally I prefer to research reliable consumer drives and use this when making ZFS storage servers, but different people do different things.

poofyhairguy Wrote:With Unraid the only way more than one HD is going down at one time is if God hates you (aka PSU catches on fire) or you are stupid and you go against Tom's recommendation to mix and match different drives.

...or sh*t happens and you are out of luck. What about silent corruption aka bit rot? How does unRAID recover files where bit rot has caused the file to become corrupt and no longer read?

poofyhairguy Wrote:As a bonus Unraid lets you upgrade the array size, one drive at a time, without losing data. With ZFS/RAID you are having to basically build a new array to change hard drive sizes (and then buy all those bigger HDs all at once).

With ZFS you can replace drives with higher capacity one at a time, over whatever time period you choose. When you replace the final drive in the vdev, the extra capacity will be available.

poofyhairguy Wrote:ZFS is a business solution. Unraid is a home media server solution.

The only reason to pick ZFS over Unraid is:

1. You want to play with ZFS
2. Your server is doing more than serving media in a capacity where write speeds matter (aka it doubles as a web server or something)
3. You have some sort of reservation for paying for Unraid

ZFS is also used by many *home* users who have discovered its many benefits over other file systems in terms of its data protection features.

To think that people would actually pay for something with lesser data protection features than something that is better and free just makes me scratch my head.

The amount of misinformation people have about ZFS in this thread is quite remarkable, but not that surprising I suppose.

For any open-minded people who wish to learn the superior features within ZFS, take a look here:
http://breden.org.uk/2008/03/02/a-home-f...using-zfs/
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poofyhairguy Offline
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Post: #44
Quote:I can't say for all RAID systems, but with ZFS you can choose your preferred level of redundancy. For example, if you're happy with the capacity of one disk for parity data then you could choose a simple 2-drive mirror, or RAID-Z1. If you want more safety then you can choose double-parity like RAID-Z2. If you want triple-parity then you can choose RAID-Z3, which allows three drives to fail before you lose any data.

But is there ANY WAY to configure ZFS to NOT stripe the data in the array so individual drives can be pulled out and read?

Quote:You can mix drives from different manufacturers if you want to with ZFS.

Of different sizes? I thought they all had to be the same size?

Basically what I am saying is that Unraid lets you have an array with different sized drives (and use all the space on those different sized drives). If ZFS CAN use different sized drives and use all the space on those drives please correct me. My understanding is that a ZFS array cannot grow like Unraid or RAID 5 can.

Quote:What about silent corruption aka bit rot? How does unRAID recover files where bit rot has caused the file to become corrupt and no longer read?

Not really a problem with a media server. A HUGE problem with a server that is acting as a business database. That is why I would never put Unraid in my office.

Quote:With ZFS you can replace drives with higher capacity one at a time, over whatever time period you choose. When you replace the final drive in the vdev, the extra capacity will be available.

So basically you are saying "Sure you can replace smaller drives with larger ones, but you won't be able to use that extra space until ALL the small drives are replaced." Is that what you are saying?

Because quite frankly for home use that sucks, and is reason alone to pay for Unraid or WHS for many people.

Quote:To think that people would actually pay for something with lesser data protection features than something that is better and free just makes me scratch my head.

What makes me scratch my head is the fact that so many people push an enterprise system for home use.

For media use what matters most:

-Data is reasonably secure so you don't have to rerip all your DVDs

-To be able to add whatever drive is cheapest on the market at the time you need more space to the array and use all the space on the drive no matter what you originally had in the array

-To be able to saturate a cheap gigabit network with large and constant reads from the server

-To be able to have single folders that span multiple drives


Unraid gives all that, and pretty much nothing more. ZFS can't do all that (unless you CAN use different sized drives in a single ZFS array and use all the space), but adds in a bunch of things that media users don't need.

Mini/Micro ITX Frontend (with SSD) + Mediaserver/NAS + Logitech Harmony + LCD/LED/Plasma TV + Nice AV Receiver + XBMC + USENET + sabnzbd + sickbeard +couchpotato

My Setup--HTPC Building Guide- Start Here--Advice on Hard Drives and SSDs--Mediaserver Guide--Harmony Guide
(This post was last modified: 2010-10-13 01:22 by poofyhairguy.)
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darkscout Offline
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Post: #45
If you have the $$ you can also put your ZIL onto SSD drives or use them as swap. Or add one as a hot spare (which it will automatically fail over onto).

Hell right now I took all my mismatched IDE drives I have left. Tossed them into a case. Made it RaidZ1 and it's an alternative server.

ZFS really blurs the line between 'device', 'partition', etc. You just add devices to a vdev which is added to a pool.

So my "home" pool could be 2, mirrored vdevs made up of 6 drives in Raidz2. Meaning 2 drives from EACH separate set of drives to fail before I lost things.

And you could always just build a backblaze for $1000 and start adding drives as you go.

http://blog.backblaze.com/2009/09/01/pet...d-storage/
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