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+--- Thread: FreeNAS versus unRAID as the operating-system for a DIY NAS? (/showthread.php?tid=82811)
- BLKMGK - 2010-10-12 05:02
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...
- BLKMGK - 2010-10-12 05:11
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...
- PANiCnz - 2010-10-12 11:07
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.
- PatrickVogeli - 2010-10-12 11:39
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.
- sWORDs - 2010-10-12 11:44
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)
- darkscout - 2010-10-12 14:58
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.
- froggit - 2010-10-12 15:22
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.
- TugboatBill - 2010-10-12 19:42
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).
- darkscout - 2010-10-12 20:20
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?name=News&file=article&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.
- poofyhairguy - 2010-10-12 22:40
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