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What NAS To Buy?
An anonymous reader writes "Currently, I'm running an old 4u Linux server for my private backup and storage needs. I could add new drives, but it's just way too bulky (and only IDE). For the sake of size and power efficiency I think about replacing it with a NAS solution, but cannot decide which one to get. The only requirements I have are capacity (>1.5TB) and RAID5. Samba/FTP/USB is enough. Since manufacturers always claim their system to be the best, I'd like to hear some suggestions from you Slashdot readers."
Something such as FreeNAS (http://www.freenas.org/) may work for you, if you purchase your own hardware. A quick rundown of what it provides: http://en.wikipedia.org/wiki/FreeNAS
I've got the WD MyBook WE 2 TB drive a few weeks ago. I haven't installed any of the MioNet software on my computer because I heard complaints about it. I've got it set up in RAID 1 mode (mode 5 needs a lot more drives). Performance is good so far. Powere consumption is around 20W, as opposed to a desktop PC at around 150W. Since it's running OpenLinux, I was able to add SSH and do more configuration of the SMB server this way. The linux partition is 2 GB; the Arm processor is somewhat underpowered for most other applications.
Using Solaris Express with ZFS. There is an extensive set of articles on how to do this at Simon's blog http://breden.org.uk/
Since you didn't really say much about other requirements, I'll recommend the NV+. I just got one on ebay and it's awesome. It just works. Shows up on the network immediately, has lots of blinking lights and a nice web config interface. 4 bays expand up to 4TB. Plus, it's a shoebox and not a gigantic 4U rack.
Before everyone tells you to go use FreeNAS or Openfiler, be aware that I spent weeks trying to get those to work.
If you want my advice on what to actually buy, do NOT go for anything from netgear. I bought a lemon from them which was advertised as a NAS solution, but was in fact a very wierd SAN implementation.
Consider trying an Airport Express basestation, with a big external USB drive. Yes, it's apple, so the feature set is "straightforward", but nothing beats having a working system instead of hundreds of dollars of useless gear.
Alternatively, I have tried a Lacie Ethernet Disk, but they used embedded xp on the damn thing and it kept borking itself every month or two. Since their software to recover the OS wipes ALL data, I don't endorse them at all any more. Waste of over $1k USD.
Final thought: buy reliable, and keep your receipts.
http://www.drobo.com/ Automatic RAID, hot-swappable and you can use any type/size/configuration of SATA drives. Upgrade as the price of drives go down. I've been using one for two months now and am very happy with it. I can watch a streaming movie while I yank out an 80GB to replace with a 500GB, and the movie doesn't even stutter once.
Get a d-link DNS323 and toss in 2x1TB drives, and you are set.
The firmware hasn't really matured until now, with FTP/iTunes/samba server, and the latest addition is a torrent client, for all your 24/7 downloading needs.
It's quite hackable, with an USB port for printer sharing, or storage with a bit of hacking.
I had horrible firmware problems the first ½ year i had it, but now it's smooth sailing
I've been using an old desktop with large HDs for years, always looking for that perfect, small NAS with minimal RAID that I could put in a corner. Unfortunately I was always frustrated since the majrotity of units were directed at business and ran over $1k (that's just too much to pay when a desktop is so cheap).
However, recently there has been a real surge in the market, with a number of more home directed products available. These often include streaming services, in some instances are OSS friendly or even hackable, and have small form factors with RAID1 or RAID5.
The best reviews I've found are at SmallNetBuilder.com... very thorough, always show the boards, etc. The best units I've found (or at least the ones that look the most interesting for my needs) are the following:
Synology DS207+
Looks like a great unit, with lots of control over the drives (RAID0, RAID1, and other drive configurations). However, it's a little pricey for a BYOD NAS ($350+). The support for NFS in external USB drives is nice, and the reviews are excellent. The fact that it doesn't have slimserver support (or not natively) is another weakness... I've been eyeing adding a squeezebox or other player to my stereo, and would like the option. One thing I can't figure out... is it worth going with the "+" unit, or is the old 207 adequate? It's a lot cheaper...
Netgear ReadyNAS Duo
This is obviously the most expensive option, and is about on par with the Synology unit from a performance perspective. I like the fact that it has Slimserver as a native option... seems very well rounded. Also has internal NFS support, which both the other units lacked. Negative seems to the weak photo sharing app (requiring a local install) and the lack of drive controls (RAIDX being the only option). The fact that the 1TB unit costs $600+ also sucks (that's with just 1 1tb drive)... I want a 1 terabyte x2 setup, and I can get a nice 1TB drive for a hell of a lot less than the $275+ (that's the difference between the 500gb and 1tb versions of this sucker). Basically means the 1 drive is a throw-away for me, which I have a hard time swallowing...
Hard choice to make... but I think I'm going to go with the Synology and two 1tb WD caviar drives I can get for $160. Total cost around $650... a little more than I wanted to spend, but this should be good for years to come.
-rt
I don't know why AC got modded troll... it's good advice. I built my file server as raid5 and am regretting it. It's the most economical, and you do get some redundancy.. but if I had to do it all over again, I'd totally go raid10.
With Raid5 .. two drives fail and your done. Unless you buy every drive at a different time from a different manufacturer, chances are under the same wear conditions, two will fail around the same time. With a raid10 .. you put all one brand on one side, all of another brand on the other side... possibly on a separate controller. Raid10 can withstand a much larger failure... and you also get some serious performance++.
raid 10 is a waist of disks and power
raid6 is the way to go
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
To reply directly to your reqs (kind of lost track of the thread there) both manfacturers have other versions of those drives that are RAID5 (the NV+ line from Netgear, other Synology units).
As for services, both can be used as FTP servers, web servers, or anything else (I think both are LAMP, I know the Synology is). The Syn unit also supports bittorrent natively.
-rt
Good idea, but skip the D201GLY2A and get a D945GCLF instead - afact its the same board approach, but its the atom version so only ~2.5W and a proper intel mobo chipset instead of the via chipset on hte D201GLY2A for the same sort of money. Not that the D201 is bad ( I have one at home and its great ), but it seems the D945 should be a better choice.
"Success is based on knowing how far to go in going too far"
Netgear's ReadyNAS line of products (originally made by a small outfit called Infrant before Netgear bought them out) strikes the best mix of NAS characteristics outside of rolling your own.
The RND4000 retails for $900 diskless, although you can occasionally find it a bit cheaper. It has four SATA inputs and uses a "drive cage"-style design to eliminate wires and allow for hot-swap; it's 9" x 8" x 5". It has gigabit ethernet interface and 3 USB ports. You can set it up as a print server, interface to a UPS, set it up to auto-copy out to a USB HDD on a particular schedule, or set it to auto-copy in from USB flash card/drive to a particular partition.
All the interface is web-based, and in addition to the usual NAS features it supports FTP and HTTP sharing of files, Active directory integration (if that floats your boat), user quotas, and other fun little stuff. The system supports automatic power-on and -off at scheduled times, a journaled file system, and spin-down of drives when not in use. My model states that it uses 60W spun down and 130W at full tilt.
It supports RAID-5 and a RAID 5-based system that Netgear/Infrant call X-RAID. X-RAID allows for dynamic expansion of capacity, which is a very nice selling point in a NAS box. Got 4x250GB drives and want to upgrade to 4x750GB? Just pull one drive at a time, wait for rebuild, and repeat until all four have been replaced. Netgear/Infrant has never gone into the specifics of how it's done, but I'm guessing the drives are partitioned and the partitions are then RAIDed to ensure drive-level failure can't cause a problem. I know I've seen people do the same thing in software on x86 machines (in LVM, maybe?), so I'd guess that's what they're up to.
I have an older Infrant ReadyNAS (the X6 ver. 2 model), and have been very pleased with it. I have heard grumbling that after the Netgear buyout the support channels have gotten a little more irritating. I haven't personally had to deal with it, so I can't vouch either way, but I do notice that the latest system update (which had been in beta a few months ago when I checked) is now listed as a proper release on their downloads section, so they appear to be maintaining the normal release schedule.
You will hear some /.ers recommend rolling your own, and they'll definitely have good arguments. $900 diskless goes a long way in small, quiet, cool PC gear. If you want a NAS system, though, I've found this to be one of the best mixes of features (particularly the dynamic expansion) available short of a full-on PC.
I used to set up my own linux fileservers... then someone else asked me to do one for them, then someone else... and so on.
So I bought a couple of the Buffalo NAS TeraStations. Slightly pricier, but worth their weight in gold for 5 second configuration.
Adaptec/Overland Storage offers the SnapServer (www.snapserver.com), which range from 250 gigabytes to well over 88 terabytes of storage space.
There is also ASA Computers (www.asacomputers.com) which is dedicated to offering Linux-supported hardware and they have many storage and iSCSI/NAS solutions as well that reach into the 30 terabyte range.
And it should be noted there are still plenty of IDE drives out there in the larger sizes. If you really want to go with SATA, then get an adapter card.
Lack of performance? Not an issue, since I've yet to see a NAS that- at the lower end pricewise- was competitive in this regard, anyway.
Or, keep the server, and drop in a new $100 mobo/chip combo that allows for better power management. Regardless, I've found things are much better with a home server than they ever were with a NAS, and my DNS, DHCP, Samba all work better, plus I now can run squeezebox.
Having just seen terabyte drives at $169ish this past weekend, the flexibility of adding storage also makes it a better solution, too.
stored on computers from birth to the grave
With Raid5 .. two drives fail and your done
Then go with RAID 6. Takes 3 failures (out of 4!) to lose data. By the way, is there any sort of setup out there with more than 2 parity drives?
Also, if you've got 4 drives in your RAID 10 setup only two drives need to fail for you to be screwed, plus you only get (theoretically) twice the performance of a single drive, as with a RAID 5 setup for the same amount of drives you get 3 times the performance.
You just got troll'd!
See www.smallnetbuilder.com. They review NAS devices regularly. As well, they have a set of NAS charts with benchmarks.
I decided to get a Thecus (N5200B) over a Netgear ReadyNAS NV+ (also a diskless). The Thecus is the fastest while the ReadyNAS appears to have the easiest method of expansion. It's been about a month, so things most likely have changed a bit. Up until recently, http://smallnetbuilder.com/ has been the most informative source I've found.
You'll note that the 2 boxes are about $650 and $850, respectively, so you're easily in the range of a cheap computer. The reason I'm leaning towards these is power usage, size, and ease of use.
If you want cheaper, you can do it. If you don't mind power/heat and a larger size, its very easy to accomplish.
I heard a lot of good from friends of mine about the Synology Cube Station CS407, and that's the one I have on order now. I like the fact it's expandable, I'm e.g. planning to run a Squeezebox server on it. It has good support, and a large user community.
Others I heard about: Intel SS4200-E (Helena Island). It exists in two versions, one with an embedded OS on a flash and one without any soft. The one with software included has not that much possibilities and is not expandable, it's in the category "it just works." For the other version, I heard installing Linux or Windows Home Server on it is a PITA...
The ReadyNAS by Infrant (recently bought by Netgear) also gets good comments.
Using RAID 1+0, you get almost 4 times the performance for reads, and 2 times for writes.
Using RAID5, you get maybe 3 times the performance for reads (if you're lucky), and writes can be slower than a single drive due to parity calculations.
Clearly, 1+0 is the preferred choice for performance (and yes, I have used both, for years)
I would still recommend RAID5, as it's worked quite well and been very economical for me, but performance-happy it is not.
Random and weird software I've written.
uhhhhh RAID6 will only support the loss of up to two drives....just like RAID10. RAID6 on the other hand doesn't use as many disks as RAID10.
Insert funny smart-ass comment here.
Just to add a bit of information to this post. I believe the RAID mode this poster is talking about is indeed RAID 10 and not RAID 1+0 or 0+1 -- stripped mirrors or mirrored stripes. This new RAID mode is supported by the linux md driver.
Linux MD RAID 10 driver page.
This RAID mode does not require an even number of discs. My understanding is that writes are much faster with RAID 10 than RAID 5 because parity checks are not necessary. However, this RAID10 mode gives you only half of your total RAID size, and RAID 5 gives you your total RAID size minus one drive in capacity.
Some useful, more detailed (and likely more accurate) information
Some performance comparison results to RAID 5. It would appear that the read performance is close to RAID 0, and the write performance is close to RAID 0 divided by two -- because every write has to be done twice. Furthermore, RAID10 can be more robust for drive failure.
You've obviously never used a Netapp box. You get what you pay for.
I don't know why AC got modded troll... it's good advice. I built my file server as raid5 and am regretting it. It's the most economical, and you do get some redundancy.. but if I had to do it all over again, I'd totally go raid10.
With Raid5 .. two drives fail and your done. Unless you buy every drive at a different time from a different manufacturer, chances are under the same wear conditions, two will fail around the same time. With a raid10 .. you put all one brand on one side, all of another brand on the other side... possibly on a separate controller. Raid10 can withstand a much larger failure... and you also get some serious performance++.
My advice is that if you can't explain how raid5 will help you, then you most likely don't need it and should use raid10.
Those that really need raid5 can explain how it is more cost effective over a given time span for them than raid10.
Oh yeah good point I forgot that you didn't need to read everything twice for RAID 10. As for RAID 5's write performance there's variations of RAID 5 like RAID-Z that try to address this.
You just got troll'd!
Not to be pedantic, but RAID10 will only guarantee data security with one drive failure. With RAID 10, there's an approximately 1/3 chance that the second drive to fail will cause you to lose all your data.
Of course, with RAID6, any two drives can fail while ensuring the safety of your data. Hot spares are a good idea and will minimize the chances of having a three drive failure.
RAID6 or RAID ADG (Advanced Data Guard or whatever you raid controller card's vendor is calling it) is SLOOOOOOW as crap. I tried it for about a month on a brand new HP Proliant that was fully loaded with a pair of quad-core XEON processors, a hardware Smart Array P800 controller card with 512MB of battery backed cache and every drive slot full of 15K rpm SAS drives configured as a RAID6 "ADG" array. My users complained so much about the slow performance of such a brand new machine that I had to dump the array off to tape, blow the machine away and reinstall making the array a RAID 0+1 instead and re-load my O/S and all the user's data. The machine is MUCH faster now, the difference is like day & night. Yes, we forfeited a bunch of storage capacity by going to RAID 0+1, but the tradeoff for performance was well worth it.
RAID is just a reliability mechanism.
RAID 0 is for performance, not reliabilty.
...what she's selling, she's got a pretty face and very nice tits.
and not to be a tremoundous nit-picker, but for 100% true data protection you can't rely just on what type of RAID set you employe. A tested backup/restore process must be put in place, anything less and you risk data loss.
Insert funny smart-ass comment here.
http://lime-technology.com/ offers UnRAID which looks very interesting. There's even a free version to try. To me, it's not just that you need X amount of storage, it's also about growth. What seems like a lot now, won't be a lot in a couple of years.
My Tech Posts on Twitter
"I don't know why AC got modded troll..."
It is not good advice, it only seems to. Let's see the typical home-grown near-site server, say three 500GB SATA disks on RAID5 for 1TB usable space. Now, go with RAID 1+0; that means you need four disks (that's 33% more money) to gain about 0.025% reliablity (over a conservative stimate that you are at 99.9% no disk will fail in 3 years, but if one fails you are 10% sure another one will fail within next week -but you must consider that if the one that fails is one from the other stripeset... which means two out of three of the remaining disks, that means 7.5% sure you will lose your data).
Now: for the same dollars go with RAID5+Hot spare: you reduce your fail window to mere hours (the time to recronstruct) upraising your riability by at least a ten factor (you go from a one week fail window to about four hours). Once the RAID is reconstructed you are again 100% safe. If a second disk fails prior for you to get a new spare (say, within a week, you know, still the same 10% probability, only this time you won't loose data), then just stop the whole think, get new disks (from a different vendor/different model), mount the dirty RAID r-o and copy (disks are much less prone to fail if only reading than r-w). And money numbers get more favourable as you add disks, which is not true with 1+0.
So, you see, RAID5+hot spare is quite a better advice both money-savvy and regarding reliability. RAID1+0 is only advisable if you have money to spend and you need the extra speed.
Take this from someone running 3PB of physical disk on a deduplicated backup environment, all on FC disk.
NAS has a place. NAS can be a fit, depending on performance expectations. If you looking to push 1GB/s sustained for 500 users, a NAS server with 4 spindles is not the right fit to meet those expectations. It will fit for an environment where you have 2 - 3 users, and need 5 - 10 MB/s.
For my home environmnet I use a QNAP ts-409pro, with 4X1TB drives in a RAID-5 config. I have a couple 750GB drives that I use to backup important data (some data is disposable). Local backups I just mir the data using robocopy. I use truecopy to encrypt a drive before using robocopy to mirror the data, then pass the data for a friend to store the drive in his safe 35 miles away.
I also have a 1tb drive in a raid-nothing config on the back of the TS-409pro, that I backup my desktops to, using Acronis. I dont keep data on my desktop, so it is mostly for just having the desktop image...
The TS-409 is a fully functioning server. It might have a slower processor, but mine has been rock solid for almost 6 months now. It does www, nfs, mysql, native ssh access, perl, windows AD, ftp, RAID-0, RAID-1, RAID-5, RAID-6, JBOD, hot-swap drives, drive upgrades (replacing 500GB, upgrading to 750GB / 1TB drives),etc, etc.
RAID-10 is overkill for the home environment. Buy a USB drive, and back your crap up once a month.
4
Now: for the same dollars go with RAID5+Hot spare: [...]
Or use RAID6, giving you essentially the best of both worlds.
Personally, I wouldn't touch RAID5 with big SATA drives with a 10 foot pole. Drives tend to go around the same time and if your second drive goes during the rebuild (which I've seen happen on several occasions) then your data is toast.
There are three types of RAID levels worth considering today. RAID6 if you need space more than speed, RAID10 if you need speed more than space, and RAID1 if you only have two drives.
www.drobostore.com
RAID is just a reliability mechanism
No, it is not.
Repeat after me: RAID is for high availability, not high reliability.
If you want your data to always be available, you want backups, incremental backups, distributed chronologically and geographically.
If you want your data to be constantly be instantly available, then RAID is what you want. You still need backups to assure the data will always be available.
Interesting, but it's not a good solution for a household with multiple computers running at odd times. What if you're at work and your wife wants to access those mp3s? She has to turn your computer on? She has to take the firewire/USB drive from your computer, including the power cables and stuff?
I have a USB drive, with four people in my household, and five computers total, it's not a viable solution for sharing all the family photos and music. You may not need a dedicated server, but at least one box has to pretty much always be on.
If you skip down, you might see my other thread:
Online storage
I guess it depends how much you have to store, but the solution I was given sounds great...
The only downside is speed, but I don't see why people really need that much speed for most things. I mean, I don't normally, for example, rotate out ALL of my mp3s on my player, just maybe a few dozen at a time; low-res photos are on my website, so I don't normally need to access the high-res versions very often... plus I'd generally work locally and then save remotely.
So I haven't tried this out yet, but I intend to... for my 30GB worth of stuff that I have right now (that's worth backing up and sharing amongst the computers), it's like $4.50/month. Sadly, I wish I could use my GoDaddy account (where I have over 100GB free), but I can only use that with FTP. Fine for me, but no one else in my family.
Stupid sexy Flanders.
"Using RAID5, you get maybe 3 times the performance for reads (if you're lucky), and writes can be slower than a single drive due to parity calculations."
This is an old idea. That doesn't mean it's wrong, but it's worth thinking about in the situation.
Low-end controllers tend to have crappy processors on them. Crappy processors cannot compute a checksum very quickly. But modern non-crappy processors are insanely fast compared to modern disk.
When you make this sort of calculation, you have to figure out what is doing the checksumming. Think about the advantages of RAID-5 with instant checksumming, then back off from those based on how slow you believe the checksumming will be.
And all such calculations (for 10 or for 5) need to consider the number of spindles.
No, he's right. He said it takes 3 failures before you lose your data. Out of a 4 drive RAID-6 setup, 2 drives will be used for parity. You can lose 2 drives and still run. The third loss takes out the array.
NAS devices suck. Either that administration is tedious and incomplete or nearly nonexistent.
Are you hoping that your NFS permissions work right? They won't, at least without massive configuration on your part. Are you relying on the data always being available? It won't be, because even the semi-expensive ones use junk hardware. Wanting high availability solutions? Don't even think about a NAS device. Most of them don't have hot-swappable power supplies, hard drives, or anything else.
They're essentially toys, overpriced, underpowered, hard to configure toys that break far too often.
This is just untrue. I work with Netapp, Bluearc, Isilon, Onstor and Panasas and none of them are toys. They're all very good, reasonably fast, easy to configure boxes. Spread across these is about 1PB of storage. They work, and they work well and none of them have the problems you list. Except maybe EMC. :)
RAID10, is a mirror of RAID5 arrays.
RAID0+1, is a RAID5 of mirrors.
No. The old nomenclature (such as "RAID10") was never defined properly so different people used different definitions. One vendor's RAID10 can be the same as another vendor's RAID0/1 so be careful.
Since 1990 or thereabouts people have taken to using the plus symbol, so
RAID0+1 is a RAID1 of RAID0s (a single mirror)
RAID1+0 is a RAID0 of RAID1s (a bunch of mirrors)
RAID5+0 adds (or stripes) a bunch of RAID5 arrays together.
You notate the RAID levels in the order they were applied; if I take 96 disks and make 12 stripe sets (RAID0) and then make six mirror pairs (RAID1) and then make a RAID5 array from them, it would be a RAID0+1+5 array. The notation is infinitely extensible and simple to learn and remember.
With any of these RAID methods make sure you pay attention to your disk controllers as well. If you have a controller go out and all the disks on that controller go with it, what happens to your array? Things to keep in mind...
You're right. And having two or more controllers does not always help - unless you intelligently distribute your RAID elements across more than one bus. And don't forget to put your power supplies on separate circuit breakers, too.
One aspect of the Synology product line that separates it from the competition is their software strategy.
The only differences between any two Synology products is the hardware. The firmware is the same for all products. You get the same platform, the same services, and applications, but they just handle more data or run faster, depending on the hardware choice. I really like that I just pay for scale. There are no "kiddie" versions of the software.
The OS is Linux (busybox), so it's very familiar. Busybox cannot be extended as endlessly as a traditional distro, but the company includes a pretty complete set of utilities, a full LAMP stack, and an impressive collection of applications. Documentation is good, including a nice integration guide for integrating your own apps with the device (http://www.synology.com/enu/support/3rd-party_application_integration.php )
All in all, it was their vision of a NAS device as a no-excuses, true server platform for my content that won me over.
"We receive as friendly that which agrees with, we resist with dislike that which opposes us" - Faraday
Sounds like you want a NAS unit with capabilities for a Small Office, Home Office (SOHO). Strangely, I find no mention of the Thecus line of NAS units. http://www.thecus.com/ These would be worth investigating. I personally run the thecus N5200, and two of my clients run the N5200 PRO's. The N5200 series are the only SOHO NAS units with 5 available slots and raid 5.
One of my clients has a ReadyNAS, so I've had the opportunity to compare all 3 units directly. Note that this unit wasn't a ReadyNAS+, but from what I've read, there's been no increase in speed. The largest difference is speed of file serving, although the web-based configuration is a factor as well. The Thecus blows the ReadyNAS out of the water. ReadyNAS gets about 10MB/s on a good day, and the Thecus N5200Pro units approach 30 MB/s. My older N5200 unit does about 20MB/s over gige.
Today's prices are even more convincing- The N5200PRO is available for about $750 at http://www.eaegis.com/, http://www.newegg.com/ has the ReadyNAS+ for about $900.
The N5200's have other advantages- 5 bays for instance. They also run linux, with the source for each model available at Thecus. They also have modules for special types of file serving, and you can even ssh to the box while it's running.
Here's the thing. I fell into NAS because I needed more storage space at home, to hold all my business data. And system backups. And stuff. I started with a home-built linux server running samba, but quickly realized that stock linux raid fails in the areas of raid expansion (adding more drives) and raid migration (let's run raid 5, now that I have enough cash to actually buy 3 drives). You can migrate, but you have to put the data somewhere else while you're doing it. I wanted a simple box that would do those things for me. On my N5200 unit, I have personally migrated from raid 1 to raid 5, and expanded the raid from 250GB to 320 GB drives. I now have 5 drives, will be expanding the raid with 750's soon. That would be have rather painful on a simple linux based server. I don't know about Freenas, but the hardware it supports is rather limited. Same thing for a zfs solution, not to mention that I'd have run Solaris -yuch.
If you're going to fully populate the unit from the start with the biggest drives available, raid migration and expansion won't mean much. The Thecus N5200PRO still wins as it's the only unit with 5 bays, so you get the full 4 TB's possible. That being said, the linux/freenas/zfs server options can be nice, because you'll have more control over your server, and can possibly be cheaper.
The big point here is that raid is not backup. raid is high availability, and you'll need some way to back it up. What do I do? Well, since the raid is HA, all I need is simple windows box with raid 0 or spanning and a few drives. That's if I'm doing CIFS. It'd be a linux box and nfs if that were what all my home/office boxes were. As long as the Thecus or the backup is up, I'm good.
Good luck on your search
The Internet has no garbage collection
Over the past 15 or so years my company has built quite a few RAID5 arrays on servers. We have used many different controllers (SCSI and ATAPI) from ultra-high priced (>$1500) hardware based ones to low cost ones. We have done it on different Operating Systems: Novell, Windows Server, Linux. We have used different software. EVERY ONE OF THEM HAS HAD A CATASTROPHIC FAILURE THAT RESULTED IN LOST DATA FOR A CLIENT. I gave up on RAID5 about 8 years ago. RAID10 (with at least one hot spare) has proven to be both more reliable and WAY better performing.
I have had some success with RAID6 on Linux, but performance is not anything like RAID10. During the same time a client has only lost data on RAID10 array ONE time. They ignored the failure of both of their hot spares (which kicked in and rebuilt failed drive properly) and continued to run without telling anyone! No fault tolerance could protect them.
One could build something similar to a NetApp for perhaps cheaper. A business shouldn't do a roll-your-own NAS and expose themselves to the what-if case of their admin dying or resigning... unless the budget absolutely dictates the cheapest solution as most home businesses do.
Yes and more. Don't let sticker shock completely rule NetApp out as a viable option. Take a look at the WAFL filesystem and other NetApp technology.
I agree and disagree. If you want high performance NAS like you'd get in a data center, then drobo definitely isn't the way to go, but if you are just looking for a simple home unit for backups and maybe storing media on, then it's not all that bad.
Think of it like an apple product, simple, elegant, streamlined, but still missing some of the advanced features you could get if you built your own.
Yes, the slow speed sucks, no, it doesn't affect streaming video / music to something like mythtv or itunes. The biggest PITA for me is that when it sleeps it takes a few seconds to wake up and spin up the disks.
I've had one for about a month and have no problem with it streaming video (divx) to my mythtv or having my mp3 collection on it for itunes, or storing all my pictures on it and accessing it from lightroom. I chose it because I had gone the "build your own" before using linux + lvm + evms + raid and decided I wanted something I didn't have to maintain or worry about. YMMV of course, depending on what you're looking for :)
Instead of a NAS, I use two Antec 900 cases with low-end pc. Each case can hold up to 9 HD (if you don't need an internal DVD), and the disks are located in 3-disk containers with a dedicated 120mm fan (yep, one fan for every 3 disks!). There is also a huge 200mm fan on top of the case and a 120mm on back. With all those fans the disks stay cool no matter how badly you ride them, and the fans can be set at the minimum speed; there is not much noise. Also there is 2xUSB and 1xfirewire ports on top of the case, which I use for the O/S.
So in a single case (which is also quite the looker) you can get 9x500GB or even 9x1TB. Of course you need to find a mobo with enough SATA (or IDE if you prefer) connectors, but 2x SATA RAID 1 cards are cheap and reliable. And you also need a good PSU (I live and die by Antec!).
I don't know where you live, but here in Canada this whole setup is quite cheap:
-mobo+cpu+2GB DDR2: 225$
-psu: 100$
-SATA RAID cards (2): 50$
-Antec 900: 125$
-9x500GB HDs: 800$
-USB stick (for the O/S): 20$
So for less than 1500$ you get a 2.2TB fully redundant storage, on which you can connect using Samba, NFS or whatever protocol your Linux O/S supports. As for myself, I use iSCSI and LVM in my client PC to connect to my 2 Antec servers so my system is completely redundant.
The only tricky part is to access the RAID cards from Linux, but even with no-name brands you can make it work with stock drivers and a good search engine...
lucm, indeed.
No, Samba doesn't have a 2GB file limit. Samba is fully 64-bit clean.
Jeremy.
I could spend much time espousing unRAID but here it is in a nutshell....
Bunch of drives of whatever size, all but the parity drive are formatted ReiserFS. One drive, the parity drive, must be as big or bigger than all others. This drive stores parity for all other drives. Files are not spanned across drives nor is parity like normal RAID. This is good in that not all drives must spin to read or write a file. this is bad in that for reading you do not have the aggregate speed of multiple drives together. For normal use at home, in my case a media server and backup solution, performance is acceptable - especially for streaming to my HTPC (XBMC on Linux).
If a single drive fails I have access to ALL data and need to replace it with a drive as big or bigger than what failed. If TWO drives fail I lose data but instead of losing the entire data set I lose just the data on those two drives. To keep from losing all data with most RAID you need spares - yucky for home use. Since the drives are standard ReiserFS I can also pull a drive and read off it's data should I need to - most RAID I'm aware of cannot do this. There are companies specializing in data restoration from various types of RAID for a reason...
So, cheap hardware, low power usage (Celeron and drives spun down), pretty safe storage of data, and it's actually not very loud - I use 5in3 SATA cages in the new box, 4in3 CM cages in the IDE. I've not had issues with mine crashing either and if you wanted an FTP server could probably be setup.
Oh 2 be fair there are some downsides. Write speed is slow, security a little weak but there is some, disk space not always used 100% efficiently, and the hardware supported while good isn't HUGE. I think you're limited to "only" 14 drives too :-P
Fire away here or on their support board if you have questions...
Build it, Drive it, Improve it! Hybridz.org
I would still recommend RAID5, as it's worked quite well and been very economical for me, but performance-happy it is not.
I'd recommend RAID6, personally. Not because two simultaneous disk failures are likely -- they're not -- but because the process of rebuilding a degraded array is very intensive and there's a good chance that if you've got a second drive that's getting close to failing, the rebuild process will trigger it.
This happened to me. Twice. I had a six-disk set, five active disks in a RAID 5 plus a hot spare. One drive dropped out and put the array in degraded mode, so the hot spare was brought in and the rebuild process started. Halfway through the rebuild, another drive failed, and obviously the whole array went with it.
The second failure was transient, so after rebooting I had five functioning disks, but the array was hosed. Thanks to the e-mails mdadm had sent me during the failure and rebuild, I knew the EXACT order that the disks were in prior to the start of the rebuild. I forcibly reconstructed the array from scratch, telling MD to treat the array as being in a valid degraded state no matter what the superblock said.
The transient failure happened again during the second rebuild attempt.
Since I didn't have backups of some of the data on the array, I crossed my fingers and tried again. This time it worked. I immediately dropped in a new drive, forced a failure on the one that had failed twice and breathed a profound sigh of relief when the rebuild completed successfully and my data all appeared to be intact.
I decided then that RAID6 is a hugely superior solution over RAID5+hot spare, because a RAID6 array will survive a second failure while rebuilding the array onto a fresh drive.
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
Yes, a faulty controller could potentially corrupt the RAID, but major data loss shouldn't happen with RAID5; the checksums would fail on the next read.
Worse:
If a hardware raid5 controller dies, you have to replace it with one exactly the same (or very compatible), or you never see your data again. Each vendor uses different checksum methods, etc.
If you use software raid, you don't have to worry about the controller, or even the motherboard dying; you can put the drives into any computer which can run the same software (OS), and read/write no prob.
Nothing to see here; Move along.
Power cycles kill HDs fast. I try my best to never cycle my HD.