Don't be afRAID (of RAID) | How to access hardware RAID-5 array with HBA and software

hi guys welcome to the art of server so in some of my recent videos i've talked about raid controllers and people have commented on those videos with concerns about raid controllers and one of those concerns is that their these rate controllers have a vendor lock-in issue and basically they're saying that if you have a hardware rate array set up and that rate controller were to fail on you then the only way to recover your rate array is to get the same exact model rate controller from the same manufacturer and that simply isn't true also there are concerns that raid arrays or raid controllers use a proprietary format that you know is blackmagic and and you don't want that you want to like you know use something that's open and people understand and and you know so uh that also by the way is not true okay there's something called a ddf which is a data disk format and that's um not necessarily an industry-wide standard but it is a specification that you can read about and people have written software for it um outside of raid controllers and so you can actually access uh your raid array without a raid controller at all and so in today's video i'm going to show you a raid array that i've already set up i have eight drives in the server today and i've got a raid controller here this let me pull it out and show you guys is an ibm m5015 and this is a lsi sas 2108 based raid controller i've got a proper battery backup for the cache we've got the raid controller chip on the heatsink and two sas ports so the rate array that i have in the server today uh i've already created it just to save you guys some time um i created with this controller and i'm going to plug all the stuff together and show you guys that right array and i actually put some data on it so you'll see that there's data on it and all that stuff and then i'm going to come back and i'm going to switch out this rate controller for a different raid controller and i'm going to show you that you can still access your data using a different raid controller now albeit from the same manufacturer because all i have around here are lsi based uh raid controllers but at least that gives you uh some indication that you know if you have a really old rate of control and you're afraid that you're no longer going to be able to get a replacement for it you don't really have to worry too much about that you can get a new array controller and still access your hardware right array and then finally at the very end of this video i'm going to show you how to access that rate array with no raid controller at all i'm going to use an hba and some software and we're going to see that we can still access our data on a hardware rate array that was created by this hardware raid controller so anyway stick around to the very end i think you guys will really find that kind of surprising if you've been afraid of using raid controllers because you've read on the internet that you will be locked into a particular vendor and that you know if you can't replace the radar raid controller that you completely lose access to your data you know none of that is true so the point of today's video is that i don't want you guys to be afraid of raid i'm not afraid of raid i don't want you guys to be afraid of raid now you know if you've been watching my channel you know i'm a huge supporter and enthusiast with zfs so i'm primarily into hbas with zfs and software raid that kind of stuff so i'm not a necessarily a huge proponent of using hardware raid these days but i'm not afraid of using it and i don't want you guys to be afraid of using it all right so before we get into this do me a favor and smash that like button today for the youtube algorithm so this video gets out to more people because i don't want people to be afraid of using hardware raid for the wrong reasons all right so i'm going to go ahead and plug my sas cable in and we're going to fire this guy up we'll get on the virtual console i'm going to show you the raid array and then we'll come back and swap things out all right guys so we have the server booted up i'm logged in on a ssh terminal and so before we get started let's run ls pci and i just want to show you that we have the raid controller in here all right so you'll see that this is a sas 2108 based raid controller it is the surveyed [Music] m5015 controller that you just saw earlier and if we run ellis scuzzy we'll see that there's already a virtual disk on that surveyed m5015 raid controller and it's showing up on the system as dev sdb i've actually already created a let's say i think probably lsp blk so sdb already has one partition which is the entire disk and i've already formatted and put some data on it so i'm going to go ahead and mount that i'll put it under the slash data folder all right so now we have it mounted under slash data it's about 3.2 terabytes and let's go in here all right so in this folder slash data that's on that raid array so actually i should show you guys the configuration of that raid array so let me run mega cli uh okay i think it's not in my path let me go ahead and yeah okay i'm gonna add the mega cli to my path so i should be able to run it now okay so here's mega cli and um well let's just do adp all info a0 just to see the raid controller okay so here we see the ibm server raid m5015 sas rate controller all right and let me show you the raid volume which is a logical drive info uh logical logical drive zero on controller zero all right so here you'll see virtual drive 0 is a raid 5 array and it's about 3.176 terabytes uh using 512 uh 512 byte size sectors and there's a parity drive uh that is about 500 gigabytes these are ancient 500 gigabyte drives here so all right so anyway you can see that this is and it's been doing a background initialization here about seven percent complete so far but anyway uh we have a raid 5 array here basically and that's what's in this slash data folder that's mounted um the sdb1 that i just mounted okay that's that raid array and in here you'll see i've got a couple of files here um oh the log files from the mega cli command showed up but okay anyway basically i have a copy of my raid versus hba video uh the original mp4 file here and i've also created a sha-1 hash and we're just going to use that to verify that the data is fully intact and so i'll just kind of show you that if i do a shot one thumb check on that file it's going to read the entire mp4 file and do a checksum and make sure it checks on matches and so indeed it does so it says ok right so we're this is a good starting point we've got the data we've got a hash of that data so this is what i'm going to do i am going to unmount this okay i'm going to unmount the raid array i'm going to shut this down and we're going to put a different raid controller in the system connected to these exact same drives all right guys so i've shut down the server and i'm going to disconnect this rate controller from my array and so as you've already seen we have a raid5 array in this on the eight drives that are in the system right now i've got some data on it and that was all created using this uh rather old raid controller so i want to swap this out okay so this is the m55015 and i'm going to be using i'm going to be using this raid controller which is a newer uh sas 2108 based let's get this to the camera here so you can see it so this is a newer lsi's genuine lsi um sas 21 no 20 2208 based raid controller this is a pcie 3 card and instead of having a battery backup unit this actually has a supercap because it's got the cash vault module that basically saves your cash um to flash uh memory all right so this is a more modern system with you know slightly better cache protection technology and all that stuff so let me kind of plug this in here okay it does require this extra module to hold the the um the super cap there all right so let me get some screwdrivers all right i'm just gonna hold this module down with a screw here and we'll also lock down the raid controller and i'm going to plug that raid 5 array that we created originally with the older raid controller i'm going to plug it into this newer raid controller all right so let's go fire this guy up and we'll see that we can still access our data all right so the server should be booted up now with the other raid controller so let's go ahead and log in all right so first thing i want to show you is that we have a different rate controller here so let me do ls pci all right so you'll see that we now have a raid controller that is based on the 2208 chipset and this is basically the 9271-8i controller alright so let's run mega cli and look at the controller alright so here we have the lsi mega raid sas 9271 controller all right so this is a different controller and let's see if we can see that same raid volume from the old controller all right so i'm going to run ld info which gives me the logical drive info on array 0 on controller 0. all right so here it is virtual drive zero raid five three point one seven six terabytes same thing as we saw earlier all right so it's recognized by the new rate controller and if we run lscuzzy indeed we see dev sdb still here but showing up instead of the serve rate m5015 it's showing up under the new controller the mega raid 9271 8i right now if everything is intact there should be a partition on that thing all right and indeed there is here's sdb and there's an sdb1 partition and i should be able to mount this just like i did in the with the previous controller so we'll mount this under flash data just as we did before and all right so successfully mounted and let's go in here and so this is the 3.2 terabyte partition and all our files are still here and in fact let's just run that checksum again make sure that our file didn't get corrupted or anything so remember when it's r when it's calculating checksum on this file it's reading the entire file and it comes back okay so that means our checksum has not changed the data is fully intact all right so this should dispel the myth that if your rate controller fails that you have to replace it with the exact same rate controller you don't necessarily have to do that now this doesn't mean that all raid controllers are cross-compatible i am using uh lsi raid controllers of different generations and so these lsi raid controllers at least the ones in the last 10 or so many years have used a format called ddf data data disk format and if you want to know more about that i'll leave a link down in the description to a file where you can read more about that um specification but basically because lsi rate controls use ddf they can basically migrate their rate arrays to different controllers there's some level of cross compatibility now sometimes you won't be able to uh downgrade a controller because as the controller imports the new uh or the old raid configuration it might update it with its own extra features or you know make some minor tweaks to the format that the old controller might not recognize so you can move to a newer controller you might not be able to move to an older controller and you might not be able to move to a controller of a different manufacturer if they're not using ddf all right so keep that in mind obviously ray controllers come from many different manufacturers and maybe like i said the ddf specification is not kind of a you know universally adopted specification for how to set up raid on disk but it is used by lsi uh or broadcom avago and you know they more or less have the majority of the market share of raid controllers um there are also other raid implementations that use ddf so it's not just uh lsi um some of the so-called fake raid and on-board raid controls intel raid controllers also use ddf okay so i don't know about other ones like high point i think high point does something different and adapttech i'm not really sure but anyway uh there is some level of cross compatibility so you don't have to worry that if your rate controller dies that you're completely screwed if you cannot find that same exact controller again all right so next step i'm going to shut this machine down i'm going to replace that rate controller with a hba card and we'll see how what happens from there all right let me unmount this and we'll shut down all right guys so we've shut down the machine uh as you saw we can still access our old raid5 array made with a from the older raid controller on this new raid controller and so now we're going to actually get rid of all raid controllers so i'm going to remove this one let me unplug the sas cables first all right so say bye-bye to the raid controller and we're going to be using a lsi hba controller so no raid functionality this is flash to it mode and i'm going to plug that right array to this hba so let me go ahead and install this and go ahead and screw this guy down too and we'll plug in the cables so now we're going to access the raid array drives using an hpa controller and we'll show you how to do that all right let's fire this guy up and go to the virtual console all right so we have the server booting up right now with the hba okay the raid disks are just as they were i've only replaced the raid controller with an hba controller so let's go ahead and log in all right so i'm going to show you first that the raid controller is now replaced with hpa all right so you'll see we no longer have a raid controller here but we have a sas controller and this is indeed based on a sas 2008 hba all right and if i run sas to flash you guys will see that this is in it mode with the latest firmware for this controller all right so now if i run lskz you'll see that i don't have a dash sdb anymore that is from some sort of rate control i just have the individual disks all right now i don't i can't access the data immediately like this but what i can do is i can take those individual disks and i can reassemble them in software so that i can access them again all right so in the way i'm going to do that i'm going to use md adm so this is a the linux software raid subsystem we'll do assemble scan and so we're basically going to scan all the drives and see if there are any raid configuration metadata that it recognizes and try to figure out how to assemble this and this actually works fairly well so there's not a lot of um extra steps you need to do so we'll go ahead and run this all right so it found a uh container that it's calling dev md ddf0 and so that ddf by the way is that data disk format that i was talking about that specification so now there are different types of um data disk formats or you know on disk formats for raid arrays uh ddf is you know adopted by uh lsi and intel and some other ones and so it's it's probably the most well most broadly adopted uh specification again not all raid controller manufacturers adopt the same specification but the linux software rate system understands these things and so it found eight drives that it has assembled into this container and so we have dev md one two one two six and so i believe i can take a look at that configuration one two six md stat here okay so here we have uh md126 is active and it's a raid five just as it was in with the hardware rate controller and if we look under dev uh md126 or let's just actually do lsplk okay so md126 has an md126p1 partition and i bet that is the partition um that we had on the raid array previously so let's go ahead and see if we can mount that okay i'm gonna mount it under slash data just as we did before with the raid controllers except this time without a raid controller just an hpa and software alright mounted successfully let's take a look slash data is 3.2 terabytes just as it was before and let's go in there and all the files are still there but before we rejoice let's run a checksum so this is going to force a read on that entire mp4 file and make sure that it's fully intact and indeed it is so here we go says okay that means that that file has not changed and so there you have it guys a hardware raid array that was migrated to a different raid controller and then migrated to an hba controller using software array to reassemble it to access that data all over again all right so guys don't be afraid of raid there are things that are posted out there that aren't not always 100 true now like i mentioned earlier not all raid controller manufacturers use the same uh specifications so that part is true there is some truth to that statement but it's not as scary as it's made out to be you can access your raid array using different controllers you can even access your raid array using software within hba all right and the linux software raid uh subsystem actually recognizes multiple formats not just ddf but ddf being the most common format you know so the majority of cases you're going to be just fine so if you lose your raid controller and you're not able to acquire replacement immediately you don't have a newer raid controller sitting around maybe you know you ordered one a replacement that still didn't work and you're in a hurry to get access to your data okay all you need is an hpa and linux software raid to reassemble your hardware rate array and access your data again all right so now that said okay and someone pointed this out in one of my previous videos and i want to make that but i totally agree with it is that raid is not a substitute for backups all right so whatever you do make sure you have backups of your data if your data is important to you but you don't have to sweat it if your raid controller dies you can still access your data using a variety of different methods all right so anyway that's it for today guys i hope you enjoyed this video and if you did be sure to give me that thumbs up and if you're new to this channel you like this sort of stuff be sure to subscribe and if you'd like to support my channel go check out my ebay store i sell all sorts of server gear including hbas that are already flashed to it mode with the latest firmware ready for your zfs servers or your unraid servers or what have you alright guys thank you very much for watching and have a great day bye [Music] [Applause]

Channel: Art of Server

Views: 2,809

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Id: 6EVjztB7z24

Length: 23min 6sec (1386 seconds)

Published: Fri Nov 05 2021