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RAID: Obsolete? New Tech BTRFS/ZFS and "traditional" RAID
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- เผยแพร่เมื่อ 14 ส.ค. 2024
- This video is the first in the storage series for managing storage in the enterprise.
This first video we talk about RAID, and the current state of the art for the "next generation" of RAID type devices. What RAID really means in terms of data integrity is shifting and this video starts the conversation.
Join us in the forums for non-swill discussion:
forum.teksyndi...
Wendell's explanation of RAID is far better than my professors in college.
Mine too
Ha Wendell and the internet is my teacher :P currently using ZFS + rsync to mhddfs backup drives absolute beast of a setup so little to worry about.
while in college I studied these topics way more deep than a youtube audience could tolerate, However Wendell's way of defining and explaining concepts is MUCH better than any teacher could give me.
Difference being, Wendell does this for a living, your Professors are paid to read a textbook and spew the information out to the students.
***** Most of the university professors I had worked in the industry and in national labs during the off season so they knew what they were talking about.
Too complicated, I'm just gonna store all my 1's on one drive, and 0's on another.
Also, subscribed.
I laughed much. Thank you, sir.
nihilusJ90, hard drives can't hold that many 1's, spindles get too heavy and break!
You have to throw some zeroes in.
as funny as this sounds, it is actually true for layer 1 of ethernet media encoding since 000000000000000 is DC voltage. cat5 cat5e cat6 needs AC at about 1MHz or higher to combat capacitance over long cables.
You would need a third drive to tell you when to switch between drives
better to partition a single drive, then mirror the 2 partitions. Yes, i actually seen someone write this in a review on amazon....
I wish this video had been around a few years ago when I first started in IT. It basically explains in around 30 mins what took me hours of reading and re-reading to understand about RAID and how it works. Thanks Wendell!
Wendell, I'm thankful that someone like you exists online and gives this free information in such a simple format. I would replace some of my profs with you buddy. Keep it up!
i did learn a lot. now it's very clear to me why everyone and their mother is using zfs and or btrfs. please keep it up. it's a very good series
You sir are spreading FUD.
More of these please D:
Give me all of these, I feel like I'm learning things!
In ECC we trust.
Until the ECC flips a bit.
Like I'm going to trust a redshirt, if he really knew what he was talking about he'd be a reoccurring character.
Wendell, your knowledge is impressive and the way you simplify complex subjects is great. Really appreciate the knowledge transfer!
L1E - Thank you! I started as a fixer of machines. An intense hobby which lead to 24 yrs of IT issues. Raid in 99 was better than a back-up. BU-ps at that time I found crashed, journal-ling of the NTFS was better than F32. Drive stability - has gotten better in the last 15 yrs. And I have moved to linux to explore their file systems. In the end - 1 is 0 - 2 is 1 - 3 is a back-up. And it is nothing - if you never Test it - rebuild a clone - from the back-up. And 4 - is learning new tech to stay current. Cheers Sir!
Man, Wendell is getting more brave with showing his face lately.
And he looks so much better with some face hair.
Happy I watched this, all of the things you mentioned as 'things you need', such as battery backups etc are already implemented on my servers. Might be worth noting that if you're running ZFS from a USB as many are, that copies of that USB are important in case that fails you.
Wendell, not sure you read these comments but: when setting up storage, like a freenas server, I always worry about the storage server itself being a single point of failure. Would be AWESOME if you could do a simple two-node storage cluster video, could be using anything, like freenas, Openfiler, OpenMediaVault, Rockstore, zfsguru or whatever else you want ;D
Two node clusters tend to have weird split-brain failure modes. Normally you'd jump from 1 node to 5 nodes so you can tolerate the failure of 2 machines.
@@NavinF thanks yes, that explains why a lot of solutions (like Ceph) prefer odd-numbers of nodes
I work as a DBA now and I´ve learned a lot from your video. It helps a lot to understand about the SAN and NAS products.
What a brave man wearing a "red" Star Trek shirt! :)
Please make more of these types of podcasty videos I can listen to while driving. I learned a lot more from this than I did any of your other videos.
I was about to say that you should have gone more in depth into how each typology worked, but after reading the comments I say that you've struck a good balance in between simplicity of understanding and technical detail, any more and quite a chunk of the audience would have simply been too confused to follow along.
Good work. Wendel. Explaining these things in that manner is no easy task.
SAS interface is also full duplex, SATA is half duplex. SAS operates at a high voltage (playing into better ECC you mentioned)
Love the detail and the explanations. Most folks don't seem to get that RAID is not a substitute for backups. Thanks for pointing that out. In the future would love to hear about setting up FreeNAS and other solutions. Would really love to hear about setting up second network just for backups or NAS to run on and securing it so it is not available to the internet. Thanks.
SyberPrepper I worked in a data center that had a second network for backups. It was trivially easy. You just need a second network port on each computer and a router. You can use file based name resolution (/etc/hosts or LMHOSTS) or you can set up a little DNS server on the LAN or make your backup server (the one that receives the files) also a DNS server. File based name resolution is the easiest to set up but a DNS server is the easiest to maintain. Keep the backup LAN on a separate subnet from the business network.
EdWittenable Excellent tips. I really appreciate it and look forward to working on it. Thanks!
The problem with "RAID is not a backup" is that it's already expensive as hell to have enough storage for an array of disks. So having to duplicate that a couple of times over just isn't reasonable for say someone building a home server in the 50+ TB range.
really loved this long video very well done and informative thank you wendel
I am not sure why TH-cam marked this a a new video. Good video Wendel, it gives some food for thought for when I start building this stuff in my flat to practice on while I am doing my degree.
Thanks Wendell, I used some of Tek Syndicate's videos on FreeNAS and NASferatu to make my own 8Tb ZFS FreeNAS box. It's been 3 months running constantly and I am very happy about it. Avoton board, Crucial 16Gb ECC, smooth sailing.
Ecellent video Wendell. I am 25 and working with enteprise backup SW (HP). People condn't emagine working with someone who needs to restore something wheterher it is a normal client, enterprise or department. Backup and the ability to restore from it are the most important thnigs that one company should invest in.
Having spent a lot of time looking into this myself, I didn't learn anything new. But this really helped make it all more coherent, practical, and simple. Much easier to pool all the information together when it comes from one source in a coherent manner, rather then bits from 20 different sources unrelated together.
Raid explained by a man who's face we had hardly seen, glad you're showing yourself more on the Tek Channel :)
This is the kind of stuff that needs to be on PBS or NPR or something like that. Everyone should know more about the technology that they use everyday! Ignorance is easy, learning and sticking with something is hard. Good one guys, I appreciate it !
Hats off to the "black swan" reference.
What about raid 0 with two usb ssds? Just for having faster and bigger external drive? (backups made elsewhere)?
Volume too low
I started doing enterprize system support in 2005 and our storage RAID controllers had memory and battery backup on every single device even then :)
i feel like in school, only i like this class.
Thanks for the video. First time looking at TEK Enterprise. keep them coming and good luck!
wow this is fantastic. there might not be as many views as the tek, but each view is going to be so valuable to us people watching... so thank you.
I learned so much today! Thanks!
wow, i wished I found this channel sooner, your an awesome tutor, this is exactly what i was looking for; keep up the good work
Worked at a major storage vendor for about 8 years before retiring. The MINIMUM we suggested was double parity. And Raid does not equal backups. (They would do snapshots from LA to Florida to NYC for one of their customers. Amazing how a bad router will kill a 60 to 100 gig transfer.....Luckily, the systems detected the problem on the fly, so the network engineers at the big company finally found the problem... A blade in a big router was resetting because it couldn't handle the multi gigabit stream...... Storage at each location? 500 gig to 1 petabyte.... Scrubs were happening periodically. The biggest problem: one brand of large sata drives where 20-30% would fail....
It's so nice to watch a video and hear someone say RAID isn't a backup from the get go and then go onto to recommend a minimum 3 copies of data. SO many people call RAID a backup, it's insane. Nice video. Keep up the good work.
I use btrfs on top of a write hole affected array to handle these situations. I’ve had write hole happen on my MDarray many many times. BTRFS just takes its sweet time and sorts itself out and I’ve never lost data in this situation. With a weekly scrub on all my arrays i eliminate bitrot too
Thank you for this very easy to understand overview of RAID and ZFS, I will definitely use this if anyone asks me what it is :) Can't wait for the next one
Amazing video! Thank you so much for your time. I have been a subscriber to the Level1Tech channel for a long time but just found out about this one and subscribed right away. I got inspired from your pfSense router video an year ago and started playing with old cheap hardware. I found some combo NW70 chipset motherboards with Intel 1037U and 4GB of RAM for $15 and I got one. It has 4 SATA ports. I have less than 2TB personal data on a 3TB drive in my desktop and 5TB movie library on a 5TB 2.5" external drive so I am thinking of buying 3 more 3TB drives and doing some learning exercises with ZFS. :)
It's been 5 years, any updated video comming ?
Way over my head but I did finish the video and learned something in the process. Thanks!
How well would ZFS handle that situation you described in the beginning, when you are rebuilding an array after you replaced a failed disk with a new one, but there is another disk failure during the rebuild process? Obviously if the second drive completely fails then the data is gone, but that's not very likely compared to partial sector corruptions, is it?
I'm wondering if it's enough to set up a Z1 for a relatively small pool of larger drives (lets say 4x 8TB). Or if it's better to set up Z2 for a larger pool of smaller drives (lets say 8x 4TB). Redundancy ratio would be the same but I want to cram this in a relatively small case, and I'd like to minimize the energy footprint as well.
I have no idea what is happening but feel smarter after watching this. Nice video. Keep up the good work.
Great overview, as I have long expected (& avoided RAID, in favor of other options) of why nothing is perfect.
Linux MD now has a journal/log feature that addresses the write hole problem. The journal has a (possibly noticeable?) performance cost for writes, but you can put it on an SSD.
8:12. I do work in enterprise. And no, RAID is not dead, no where near it. While you can boot a host from most SANS (Boot from SAN), no one uses it. So the hosts are typically booted from 15k SAS Raid5 attached to a controller (perc6,h700 or similar) 90% of infrastructures I see on a day to day basis use that configuration. SANS are typically used for databases, Active Directory, mail servers and more commonly now Vmware. The VM hosts are clustered for redundancy, but they boot from their own drives.
Secondly, SANS (EMC/Dell Compellent) don't do anything fancy with raid.(Though i'm not sure what you meant by "More advanced than raid"? Do you mean things like Cloning/Snapshots/Replays? )
Both EMC and Dell's SANS rely on the underlying raid structure, they really don't do anything fancy, its just traditional RAID. Though with the growing size of disks Raid10 Dual Mirror and R6 Dual parity are now more common. EMC has a sniffer which runs across the drives checking for errors,(media errors/soft scsi errors/Sector errors) Compellent has a raid scrub which does the same thing. Both storage arrays are actually software raid controllers, The Flare (EMC) And SCOS (Compellent) does all the work. The difference,as you said, are the drives themselves. SAS and enterprise class SATA drive are infinitely better at self checking,(Keep your firmware up to date kids) Fibre channel drives are the best solution (But stupidly expensive).
So in conclusion
1) Raid is NOT DEAD.
2) Buy enterprise class Disks if you really value your data (even for a home solution)
3) Backup you Data to tape. (Currently the only long term solution)
4) Sans are not an all in solution(Sans can and do loose data as well, so have a backup)
How do you recommend mounting a hard drive on the wall?
hahahahahahahahahahahahahahahahahahahahahahaha
Daniel Reimer thermal paste ?
Make a file or directory and name it "the wall", then use the mount command and mount the drive to "the wall". :P
Howlingmad-wolf XD I will mount all my flash drives on "The Splonge!"
The Donut Deflector YOUR NOT A YES MAN ARE YOU!!!!!! Well now we're gettin' somewhere!
But I think I would prefer to mount my drives to "42".
The main advantage of a battery-backed hardware controller is you can cache writes on the controller to improve performance. However with copy on write file-systems losing a cache would not be catastrophic. ZFS also lets you use an SSD (preferably 2 in RAID 1) as a write cache, and since a good enterpise SSD has enough onboard capacitosr to flush it's cache to disk, you gain very little advantages with hardware RAID.
Windows really should open up it's block device subsystem so we can get a decent file-system on it.
I learned a lot from Officer Riker with a sweet tooth :thumbsup:
Wow this is good overview. In my day job, I'm a Shared Storage Architect so I know storage. I was really impressed by depth of this video. O BTW hardware RAID will not die any time soon because of big iron.
Thanks, I use from 3 year zfs on nas4free old computer workstation (hp 8300) and works great. I'm very satisfied from zfs the project born without a specific strategy from our company. I only have the need to have a storage on network to put files backup and disk images.
Starts with 5 disks of 500gb each raidz5 and at the starts of 2019 grow with 5 disks of 1tb each.
I'm very proud for this and at this days that nas is fundamental for our daily job.
My 50c.. Nothing more
Fabbri
Instead of ZFS, you should mention LVM that is widely available and it's baked natively in an ubuntu server installation. I recently played with it and I need to admit that so far, so good it's working great. I had 2 drives one 2TB second 5TB and it let me do the 1 Raid using 2 drives and I am still able to use the other 3TB storage space! With only raid technology, the other 3 TB would be lost!
ZFS is in fact not just an filesystem. It is a filesystem plus LVM plus other storage management. Do it the ZFS way is more easy because you are dealing just one tool set.
Really nice video and a very pleasant voice to listen to. Good job, sir!
Thanks, very useful. I'll be using ZFS for my NAS and BTRFS for backup drives.
It's good to be late and read all the comments piled up for the last 3 years. Hope you see this message and make a video this year about the current status of raid in 2019.
Very cool video, you are very good at presenting.
+Alexandre Létourneau I just wish he was as good at researching and getting his facts straight.
+Bu Jin ;P
Great video. I had no idea there were this many potential storage problems to consider.
This is one of the better videos out there abut raid controllers / SW solutions. Good work.
Watching this after two years. Wendell you awesome man.
Extremely informative as usual, but i have to know what your opinion is regarding RAID 0 SSD's outside of the enterprise and business space. I personally run three SATA SSD's in a windows disk management software RAID, is it really that bad ?
Well you learn something every day... no not the raid / zfs stuff that I already knew, but I did learn this en.wikipedia.org/wiki/Black_swan_theory
I am in geek heaven. Firing up the popcorn during the intermission, ready for part two.
Yup, I work in a Windows shop I maintain with a crew of 8 others over 10,000 windows servers. It was good to learn about butter fs and the rest. We also have many NAS and SAN devices so this is all good stuff! Thanks!
MidwestMotoRider Another channel has a recent video about how BTRFS failed suddenly. It may not be ready for mission critical deployment.
23.05 ZFS is only going to loose whatever data hadn't been committed to disk in the last sync transaction. Which means only a handful of files could be affected at most, and even with that, you still have whatever the last consistent state was. It's NOT at all like losing power on an Raid5 setup. In fact, it's better better to lose power on a ZFS Raidz setup, than it would be to lose power on a single NTFS drive.
2019: BTRFS is *still* 4-5 years behind ZFS, and will continue to be for the forseeable future :b
In 2020 don't use BTRFS for anything other than snapshots...
@@sbdnsngdsnsns31312 because only idiots use BTRFS for RAID
+TekEnterprise - I'm not trying to troll you, your knowledge is pretty advanced but I'd like to point a few things out.
First - the Perc6 is an LSI controller so no need to go find one. Your comment about RAID5 not being X number of drives plus a parity drive is true but that is because that is called RAID3. Personal opinion here, software or hardware RAID5 is crap and will ALWAYS bite you in the ass eventually. RAID6 was invented specifically because RAID5 is so bad. I don't trust either of them and I look suspiciously at anyone who does. Stick with hardware based RAID1 in a professional environment, though software RAID1 at home is fine and probably a better idea because RAID on consumer based motherboards is crap. OH - a SAN is not just a computer with storage, a SAN is a NETWORK of storage devices. I think it's funny when people buy a single storage array and think they have a SAN. Personally, everything I do is either RAID1 or RAID10 and when I say RAID10 I mean RAID1+0. All disks are mirrored first and then a RAID0 is striped across them. And because read and write speeds degrade as you get further out on the platter, you can stripe file systems across the RAID10 to lock in performance bands - typically in thirds. Also make sure you don't get stuck with RAID 0/1 - some people call this RAID10 but it is not. It's two RAID0s mirrored and a bitch to rebuild. I know you stressed backups and they have their uses, but they aren't helpful in an enterprise environment - they just take too long and are often corrupt. You are better off with snapshots, remote mirroring or transactional replication. Good luck in the future.
Holy shit I love those kind of answers. Both of you, do not stop talking, like ever.
These are amazing! Keep them coming guys, thanks for everything you do!
I am building home NAS in 2020 using old computer hardware and am trying to choose between OMV5 (RAID) and TrueNAS (ZFS). My hardware meets the basic requirements of TrueNAS (16GB RAMs, i3 CPU) and I really like the new UI however when you go to TrueNAS blog page, its full of comments from ppl loosing their data for one reason or other which is really concerning. You can also see youtube full of negative comments on FreeNAS solution. I'd really like to use TrueNAS for my home server but I feel like it will hit me back sometime in future when my HDD starts failing.
This went a bit over my head, but then again I am just starting to learn about these topics.
I guess for the laymen out there, we want to know do we need to create a ZFS home-server from now on?
Nice video. Is there an added benefit when flashing your lsi raidcontroller to IT to leave the bbu on with zfs ?
Great video, been having the arguments with other Tech guys for years about why traditional RAID is bad!
I am a typical home user. I understand the reasons for using multiple drives, but can i start with just one? If i buy a NAS with one hard drive, can i use it to back up my PC? (in case my PC hard drive fails) Then add more drives later over time?
Superb videos, thanks.
would a second internal hard drive as a "backup only" drive be a good idea? or would getting a Blu Ray burner and burning data to blu rays be a better backup method
Amazing video Wendell, very informative. This was the video that convinced me to donate to you all!
Suppose you run encryption (LUKS) on top of an md array? Wouldn't it immediately notice bitrot because it couldn't decrypt? Also does it matter which filesystem is used in that case?
Love the video, cant wait for part 2
Great information on RAID arrays and the like. Information anyone handling critical (or mass amounts) of data should know. #ZFS #BTRFS
I have a hardware RAID controller for one test box, with enterprise drives to match but I also have eight or so different consumer drives that are sitting unused. ZFS sounds like a good candidate for those.
Thank you.
24:21 --- ZFS 8gb ram overhead.
Kindest regards.
Wendell, Thank you for such an expert and well presented explanation. Are you familiar with Synology Hybrid RAID (SHR)? After watching your explanation I am curious as to whether or not SHR provides reliable data integrity. Any advice would be greatly appreciated.
I'm sitting here staring at my server with a raid card (5 drive raid 5) and feel like screaming in fear lol
And you are right so, RAID5 is dead (if used with larger then 500GB drives)
Ha oh yeah. I've got 5 3TB drives
I had a two drive failure at work on a RAID 5. I had a boss who believed that RAIDs were some how magical unicorns that could never fail. BAM... then they attempted to rebuild the RAID not knowing that two drives failed (assumed one). Complete lobotomy and a LOT of I told-you-so's. Someone high up on the food chain thought that RAID arrays were magical unicorns... cuz they are RAIDs. We now have better policies in place, back-up to LTO6 tape (in triplicate) as well as a second, much larger array in RAID 6 with four hot-spares. I consider that "reasonable" but it was like pulling teeth to get all of the purchases authorized even AFTER a fatal crash with data loss.
If you you have less than 12TB total you should be fine.... Mostly.
That's what I have lol 5x3TB = 15TB raw, 12TB usable. I'm rebuilding the server though using FreeNAS with 8 drives
well I kind of understand each file system management better now so i'm guessing i'm looking for more of a mirrored type storage. say with two or three drives where each drive has the exact same files but instead of copying the same files to each drive I could save the same files to all drives at the same time, whether it's two or more drives ???
So what would be the best way to store video's? I was using FlexRaid and had 2 out of 3 hard drives fail. Major problem was I was using Seagate. Within six month's of the build I had 2 hard drives fail and after getting the drives replaced again Seagates failed again. I was using this in Plex. Having more that 300 DVD's in my collection I would rather not have to manually put the collection in every time a hard drive fails. I would rather have some type of recovery available. Any suggestions how how to do that?
Can't wait for part 2. Keep them coming, great topic.
pedantic. great word! all kinds of clever. now im having an issue where my FreeNAS setup isn't being discovered on my windows network even after configuring drives and CIFS. after looking at the routers, firewalls and just about everything else I can find, I should have addressed nothing! very frustrating. this has led me down this path, rockstor, ubuntu server, ect.. all the way to this video. which is the most simplest nasware, paid or free to help me get this box up and running?? also, which file system would you recommend for (6) 1tb drives while still maintaining some redundancy and maximum storage?? It's now 2018, btrfs good to use now for raid 5 or 6? or lvm for rockstor.. im so confused.
Beautifully done. Thanks!
and another question. should i configure my raid (raid5) drives through hardware, then what file system on top of that? if using rockstor... lvm or btrfs
Your voice is so soothing.
There is one problem. If you write all zeroes to a file in ZFS, nothing actually gets stored. ZFS just logs those blocks as being empty.
great...and i just setup up an RAID 5 on my home server >_
I'm just looking for an overkill (enthusiast) solution for a decent way to keep my data safe on a homemade NAS. I'm leaning toward the BTRFS/ZFS route due to your explanation.
very useful video! it helped me to clear out some basic misinformation/lack of knowledge. keep up with a good work.
You should do a follow-up on this video exploring ZFS on Linux and BSD and BTRFS on Linux.
Boiler Snake Merch! Also. We need more enterprise channel!
Great, please continue providing this type of content.
With windows server 2016 comes ReFS which is similar to ZFS. Not as much RAM usage but much slower; can be sped up with SSD caching though.
This video was very useful and informative. Well done!
Great video! Jampacked with info. Clear, coherent and to the point without any unnecessary fluff. Would you recommend btrfs for raid5 or 6 today?