My first NAS should be arriving on Thursday, a QNAP TS-251. I purchased (2) 4TB WD Red drives to go in. I know that RAID 1 will mirror the drives, giving me only 4TB of storage. In the event one of the drives fails, I still have my data on the other drive. I currently backup my critical data (documents and photos) to multiple drives. My NAS will be used to store videos, audio, and pictures. This data is backed up on a disconnected external drive already, the NAS will be always on for other devices on my network. Does it make sense to use RAID 1 on this NAS or should I just set these drives up as single drives. I can always run a folder sync on a daily basis to backup any critical data on these drives to other drives (located in other computers on my network).
First NAS, should I use RAID?
- Thread starter monkeyboy311
- Start date
dave_the_nerd
Lifer
- Feb 25, 2011
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RAID is not a backup, RAID is for uptime.
If you are syncing to another device or to a cloud backup service like Crashplan/Backblaze, you're backed up and that's awesome.
Use RAID if:
1) You want contiguous space (striped RAID, not applicable here.)
2) Your wife will divorce you if the Minecraft server, PLEX server, or other thing that uses the NAS as a storage backend, goes down for a day or two. Or three. Depending on how much data you have to restore.
3) You want to be cool.
If none of those apply, don't bother using RAID.
If you are syncing to another device or to a cloud backup service like Crashplan/Backblaze, you're backed up and that's awesome.
Use RAID if:
1) You want contiguous space (striped RAID, not applicable here.)
2) Your wife will divorce you if the Minecraft server, PLEX server, or other thing that uses the NAS as a storage backend, goes down for a day or two. Or three. Depending on how much data you have to restore.
3) You want to be cool.
If none of those apply, don't bother using RAID.
LOL, thanks for the info. With the reading I've been doing, sounds like RAID is "the thing" to use when getting a NAS. I will continue to do what I do now, backup critical data to multiple drives / cloud manually or using a sync program.
I've been reading up on JBOD and it is something I am interested in. I would like my (2) 4TB drives to be (1) 8TB drive. Sounds like JBOD will do this. Question is, what happens if (1) drive dies, is all data lost or just the data on the drive that died?
dave_the_nerd
Lifer
- Feb 25, 2011
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.sdrawkcab taht evah uoY.
JBOD is Just A Bunch Of Disks. If you have a pair of 4TB drives, you have a pair of four terabyte drives.
Striping them together with RAID-0 would be one way of making the drives appear as a single 8TB drive. If one drive died, all the data would be lost.
dave_the_nerd
Lifer
- Feb 25, 2011
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If you have a NAS with lots of drive bays, it makes sense to use parity RAID (RAID-5 or a software equivalent) simply because individual drives are very large and not very expensive. A home user doesn't need 24/7/365 uptime, but if you're lucky and you can rebuild a RAID instead of having to rebuild the system from backups, you might save 2-3 days of semi-downtime and some inconvenience.
For dual drive enclosures, it's less useful because you're losing 50% of your storage space and doubling the cost of your storage for less practical benefit.
Hi there.
I would prefer to setup a RAID rather than having JBOD setup in the NAS.
That's because RAID 1 provides fault tolerance from disk errors and failure of all but one of the drives. Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing. Array continues to operate so long as at least one drive is functioning.
However, just keep in mind that RAID 1 is not a substitute for backup since there are a lot of risks that it can't protect against - it just give you some additional redundancy. For instance:
- If you accidentally delete a file, it will instantly be removed from both mirrored copies.
- If your disk is corrupted by a software bug or virus, the corruption will be done to both mirrored copies simultaneously.
- If you're hit by a bad enough power surge, it'll probably fry both disks at the same time, etc.
Hope this helps and feel free to ask any questions you may have.
Cheers!
I would prefer to setup a RAID rather than having JBOD setup in the NAS.
That's because RAID 1 provides fault tolerance from disk errors and failure of all but one of the drives. Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing. Array continues to operate so long as at least one drive is functioning.
However, just keep in mind that RAID 1 is not a substitute for backup since there are a lot of risks that it can't protect against - it just give you some additional redundancy. For instance:
- If you accidentally delete a file, it will instantly be removed from both mirrored copies.
- If your disk is corrupted by a software bug or virus, the corruption will be done to both mirrored copies simultaneously.
- If you're hit by a bad enough power surge, it'll probably fry both disks at the same time, etc.
Hope this helps and feel free to ask any questions you may have.
Cheers!
Michael
Elite member
- Nov 19, 1999
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I used RAID 5 and I back-up. RAID 5 (4 4TB drives) costs me one drive but maybe saves me a few days until I can get a replacement drive and then figure out what files were lost and restore from other sources.
For the average home use, I doubt it is worth it, but I travel a lot and it is good if my NAS can still function if one drive goes down and I am on the road.
Otherwise, do not bother and and just back-up.
Michael
For the average home use, I doubt it is worth it, but I travel a lot and it is good if my NAS can still function if one drive goes down and I am on the road.
Otherwise, do not bother and and just back-up.
Michael
@OP: consider reliable storage of the 21st Century and get yourself a ZFS NAS. Easy, free and modern technology that grants formidable protection to your data. RAID is of the 20st century and has never fulfilled its original intention: Redundant Array of Inexpensive Disks.
Physically, WD Green and WD Red are the same drive. This does not apply to WD Red Pro, though. Neither to the 'RE4' series.
No. RAID is for Redundancy, and many people use it to mitigate drive failure. That is a perfectly valid reason. Using RAID for 'uptime' as you suggest is outdated. We use High Availability for that, today. Update your outdated doctrine!
You do not need WD Red for NAS systems that utilise Linux/BSD software RAID. That is a scam of harddrive manufacturers to let you pay more bucks for some simple firmware tweaks you used to get for free in the past. If you live outside the EU, the two years of additional warranty may be a valid reason, though.
Physically, WD Green and WD Red are the same drive. This does not apply to WD Red Pro, though. Neither to the 'RE4' series.
Thanks for the comments. I chose the QNAP NAS for its simplicity over a DIY NAS (like FreeNAS) My main purpose for this NAS as a file server for video, audio, and photos. I've done hours and hours of reading the Pros and Cons of using RAID (any type of RAID) and I don't see why its necessary unless you are a business where data access is critical. If one of my drives go out, I will simply put in a new drive and copy my backup data to the new drive. For me, how is this different than having a RAID setup where the NAS copies this data for me to the new drive? (which I've read can take hour/days and may put more stress on the other drive) Using RAID, I still have to backup this data to another device, so that leaves me with (3) copies (2 on the NAS and 1 external). If I don't use RAID and each drive is setup as a single disk, I have 8TB of data vs 4TB with RAID. I then only have (1) copy of the NAS and (1) copy on an external drive. Regarding WD Red vs Green, the $10 price difference was a no brainier to get the better drive (warranty + firmware). I understand where RAID is good for certain people/companies, but I don't see why it would be beneficial in my case (or any home users for that matter). I posted a similar question on another forum and a user stated I was making a "NAS newbie mistake" for not using RAID. I still don't see how this is a mistake, maybe someone can explain...
Do you not have any valuable data? No pictures of your youth, weddings, no important documents? If yes, how do you protect them?
dave_the_nerd
Lifer
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Yes, but... now comes the fun part
What are you making backups of? Of your legacy storage?
As you know, legacy storage of the 2nd generation does not provide any protection to your data. Even worse, it cannot even detect corruption! So any corruption will automatically spread to your backups, undetected. You can have a thousand backups, only to notice your wedding pictures have artefacts, or your archives have become damaged.
If you care about your data, the first and foremost thing you need is the capability to detect corruption. The capability to correct corruption comes after that. Because with proper backups you can manually restore the last known good version of that file. So i would assert that detection of corruption is more important than actually correcting the corruption.
Fortunately, ZFS does both: it always detects corruption sooner or later - even with defunct memory - allowing you to take appropriate measures. And it corrects all corruption provided enough redundancy is available to make this possible, and your RAM memory is in good enough shape.
That is why i say ZFS is storage of the 21st century, and legacy storage like RAID + NTFS or Ext4 is storage of the 20st century, where corruption is normal.
What are you making backups of? Of your legacy storage?
As you know, legacy storage of the 2nd generation does not provide any protection to your data. Even worse, it cannot even detect corruption! So any corruption will automatically spread to your backups, undetected. You can have a thousand backups, only to notice your wedding pictures have artefacts, or your archives have become damaged.
If you care about your data, the first and foremost thing you need is the capability to detect corruption. The capability to correct corruption comes after that. Because with proper backups you can manually restore the last known good version of that file. So i would assert that detection of corruption is more important than actually correcting the corruption.
Fortunately, ZFS does both: it always detects corruption sooner or later - even with defunct memory - allowing you to take appropriate measures. And it corrects all corruption provided enough redundancy is available to make this possible, and your RAM memory is in good enough shape.
That is why i say ZFS is storage of the 21st century, and legacy storage like RAID + NTFS or Ext4 is storage of the 20st century, where corruption is normal.
I have (3) backups. Local copy, external copy (external hard drive not connected), and cloud copy (Amazon S3/Flickr). For really important data, I actually store another copy off site at a relatives house. If I were to use RAID, I would have (4) copies, since the RAID array would have (2). This is where I don't see the benefit, since if the RAID array fails all together, gets stolen, blows up, I lose these (2) copies. I am not trying to cause an arguments, just trying to understand the benefit of RAID for a home user.
dave_the_nerd
Lifer
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Redundancy "mitigates" drive failure because there's no downtime during a RAID rebuild - it continues to operate in a degraded state. RAID - and ZFS, for that matter - doesn't protect against data loss due to human error, scripts run amok, etc.
You need regular backups, period, or you will (will, not might) lose data, RAID or not.
HA (clustered) storage systems exist (both for SAN and NAS applications), but they're still using disks arranged in fundamentally RAID-like arrangements. (Striping for speed and IOPs, parity or mirroring for fault tolerance/protection, etc.)
dave_the_nerd
Lifer
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But most likely, you are making backups from legacy storage. Thus, you will never really know your backups are actually good, until you inspect them manually. Though i think you are pretty safe, you would have much more assurance if you were to adopt 3rd generation storage such as ZFS. That allows you to know your storage is well protected, not assume.
RAID has only benefit that it can protect against disk failure. But it does not protect against bad sectors or corruption, and still employs legacy 2nd generation filesystems which do not offer any protection to your data at all. It only protects the integrity of the filesystem in case of lost recent writes, such as the loss of data in DRAM chip of a harddrive. That is the only protection you enjoy.
So the benefit of RAID is very marginal - backups are superior. But the benefits of ZFS to home users is much more substantial. Particularly when utilising ZFS' ability to make snapshots of your data.
The downtime part does not have anything to do with it. Data Availability != Data Protection. Many people - particularly home users - use redundancy to allow their data to survive a disk failure, not to increase Availability (uptime).
You may suggest a backup, but very few people that store 10TB+ of data are willing to spend double the amount of money on 1:1 backups. And they do not need to. If they have a reliable storage solution they can do without backups for the bulk data, only using backups for their most precious data such as personal photos, documents, etc.
Actually, ZFS does or at least can protect against viruses, human error and other risks that traditionally a backup was the only defence against. ZFS employs snapshots so you make a point in time you can return to, much like a backup can. Even if a virus infects all your files or you accidentally delete that important folder, ZFS with snapshots can save the day!
The doctrine RAID is not a backup is outdated because both RAID, ZFS and backups have overlapping protections and neither of them protects against all risks. Only a good combination of 3rd generation storage + backups will grant formidable protection to your data.
And again, uptime / availability has nothing to do with it. For home users having the data available 24/7/365 without one hitch is not important. What is important is that they do not lose their data. The data has to survive time, not be available at any point in time. Or at least, that is not their prime concern. They would happily save a lot of money to accept 99% availability instead of 99,9999%. But they do not want to lose their valuable data.
You do not need RAID or ZFS or redundancy for high availability. The fact that often such configurations are used is only because of the combination of the benefits of redundancy and availability, not because it is a necessity to have redundancy with High Availability.
https://en.wikipedia.org/wiki/Ad_hominem
Essence_of_War
Platinum Member
- Feb 21, 2013
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CiPHER's claim wasn't about the number or safety of your back-ups it was mostly about silent data corruption, which can happen, and can be propagated into backups without being caught. It's a thing. It does happen. When configured correctly ZFS really does prevent it. Does it make sense tossing out the QNAP unit, and either rolling your own BSD/Linux/FreeNAS/NAS4Free NAS-box with ZFS? I'm inclined to say "probably not" and the fact that you purchased a turn-key product makes me think that this is not particularly high on the list of things that you want to do either.
The real answer to your question has already been given by dave_the_nerd. For a 2-bay NAS with 4TB HDDs, there are only two real reasons to use a RAID (fine, fine, being cool is a third): you need more than 4TB of contiguous of storage, or your data cannot be unavailable while you restore from a backup.
If you have less than 4TB of data, you could do worse than setting them up in a RAID-1 so that it was a bit less of a hassle if a drive fails. Rather than having to restore from backups, you'd only have to pop in a new drive, start the rebuild (or perhaps QNAP's management software automates this, turnkey, yay!) and you'd still have your data at your fingertips the whole time. It's not a bad idea, it's also not necessary.
I would go along with that. ZFS may not be worth the trouble for everyone, but it would provide additional protection.
I build my own computers, so using something like FreeNAS doesn't scare me. I just don't have the free time that I use to have, so I am worried about the maintenance portion of it. I played around with FreeNAS years ago (~8) by installing it on an old desktop computer. I don't recall what file system it was, probably not ZFS, it seems to work well. Over the weekend I was debating on buying a Dell PowerEdge server (one of the budget ones) and installing FreeNAS. I didn't realize how hardware hungry FreeNAS is, because of ZFS?. I estimated it would cost me about $400 minimum if I went this route. Not that bad. One of the things I dont like about this QNAP is it only has (2) bays. Getting the 4 bay model cost double the price, which it uses the same hardware as the 2 bay model.
dave_the_nerd
Lifer
- Feb 25, 2011
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FreeNAS system requirements are artificially inflated - ZFS can run with a lot less, just not with all the features. (Mostly performance/caching.) Check out NAS4Free some time, if you want to mess around with that.
I run ZFS on my AMD Geode LX 500MHz single core with a maximum of 1GiB RAM installed, and it runs just great. It just will not run at the maximum potential performance because of the limited RAM. But that is another issue.
You say $400 minimum. I recommend J1900-based ZFS NAS systems that cost around $150 without disks or casing, but with Motherboard, CPU, Heatsink, RAM and power supply. That is a pretty good deal, and very power efficient at only 12W at the wall socket, as well as a relatively powerful quadcore 64-bit processor and a decent 8GiB of RAM.
Compare that with the shitty ARM chips with 1GiB you get with pre-made off-the-shelf NAS products like QNAP and Synology for TWICE the amount of money. But you should realise that setting up a ZFS NAS takes a little bit more time to get used to how ZFS works. But with FreeNAS, NAS4Free or ZFSguru this should not take you more than a couple of hours. And once setup, ZFS is very low on maintenance.
I regularly hear people running ZFSguru for multiple years without them having done any maintenance on them. ZFS fixes all errors automatically. The only thing you need to do is check whether it lost any disks -- then you need to act. But otherwise it runs very smoothly.
You say $400 minimum. I recommend J1900-based ZFS NAS systems that cost around $150 without disks or casing, but with Motherboard, CPU, Heatsink, RAM and power supply. That is a pretty good deal, and very power efficient at only 12W at the wall socket, as well as a relatively powerful quadcore 64-bit processor and a decent 8GiB of RAM.
Compare that with the shitty ARM chips with 1GiB you get with pre-made off-the-shelf NAS products like QNAP and Synology for TWICE the amount of money. But you should realise that setting up a ZFS NAS takes a little bit more time to get used to how ZFS works. But with FreeNAS, NAS4Free or ZFSguru this should not take you more than a couple of hours. And once setup, ZFS is very low on maintenance.
I regularly hear people running ZFSguru for multiple years without them having done any maintenance on them. ZFS fixes all errors automatically. The only thing you need to do is check whether it lost any disks -- then you need to act. But otherwise it runs very smoothly.
dave_the_nerd
Lifer
- Feb 25, 2011
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QNAP TS-251 uses a Celeron J1800. (Dual core, 2.4GHz.) Because transcoding.
Setting up a zpool isn't particularly more complex than configuring and formatting any other type of software RAID.
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