@dafyre said in Linux RAID Question - Software or "Hardware" ?:

@anthonyh said in Linux RAID Question - Software or "Hardware" ?:

@anthonyh said in Linux RAID Question - Software or "Hardware" ?:

@dafyre said in Linux RAID Question - Software or "Hardware" ?:

@marcinozga said in Linux RAID Question - Software or "Hardware" ?:

My money is on fake RAID you got there. So use md.

@marcinozga said in Linux RAID Question - Software or "Hardware" ?:

My money is on fake RAID you got there. So use md.

Also because you already use MD. :-)

You know what, I can even move the two disks to my new workstation and not have to transfer any data.

I think the answer may have been found... :D

Actually even better, I can break the RAID 1 on my current box and convert it to non-RAID, then move one of the disks to my new workstation and convert it back to RAID 1. If done right, I think I can do it all without any data loss too.

I'd prefer to just move the two disks and not have to transfer any data... but that's just me.

Yeah. I'll need to copy my home directory to the SSD in my current box before doing that though. That might be easier than breaking/re-creating the RAID. I'm not quite ready to "switch" yet. Hmm...

One of the confusing pieces here is that Linux actually does things more clearly but the Windows world is so confusing that if you carry that confusion into the Linux world, it makes things harder. Windows rarely uses or discloses the names of their product components. So Windows Software RAID is used to describe part of the Windows OS. But what if you have software RAID on Windows that is not Windows Software RAID? Windows Admins typically have no good terminology to discuss this, even though it is common. They just.... don't know what's going on and don't document it. But in Linux, we have the terms on hand all of the time (MD, ZFS, whatever.) So the Linux side isn't as bad as it seems, but if you are used to a weird blend of generic names being used as if they are specifics from the Windows world and assume that the Linux world is just as crazy, then it seems crazy.

That list makes hardware RAID sound safer than ZFS, which is probably not quite true. But is the case is that the average implementation of hardware RAID is quite a bit safer than the average implementation of ZFS software RAID. Hardware RAID "handles everything for you" protecting you from most bad decisions. ZFS leaves all the nitty gritty details up to you which makes it super, duper easy to mess something up and leave yourself vulnerable. This is exacerbated by the Cult of ZFS problem and loads of misinformation swirling about its use. So the average person using ZFS is not even remotely prepared for what is needed to use it safely.

Some problems that we see people have when using ZFS without fully understanding storage:

Believing that ZFS doesn't use RAID (this is extremely common.) Believing that RAIDZ is magic, rather than a brand name, and that normal RAID concerns do not apply. So we often see people implement RAID 5 in reckless, insane situations using "it's RAIDZ" as an excuse as if RAIDZ isn't just RAID 5 - literally just a brand name for RAID 5. Treating common features common to all RAID systems as "unique" and believing that ZFS has feature after feature of protection that makes the need to protect against storage failure unnecessary. Not understanding hot swap and blind swap differences and creating systems that they do not know how to address should a drive fail. Believing that ZFS being magic is not at risk from power loss and failing to protect caches from power issues - something that they are not normally used to dealing with as hardware RAID does this for you. Not understanding the CPU and memory needs of ZFS, especially with features like dedupe and RAIDZ3. Ignoring common RAID knowledge and thinking that using ZFS means not using mirroring technologies.

@coliver said in Why the SMB Still Needs Hardware RAID:

@scottalanmiller said in Why the SMB Still Needs Hardware RAID:

@coliver said in Why the SMB Still Needs Hardware RAID:

@scottalanmiller said in Why the SMB Still Needs Hardware RAID:

@coliver said in Why the SMB Still Needs Hardware RAID:

@scottalanmiller said in Why the SMB Still Needs Hardware RAID:

@coliver said in Why the SMB Still Needs Hardware RAID:

@travisdh1 said in Why the SMB Still Needs Hardware RAID:

@dafyre said in Why the SMB Still Needs Hardware RAID:

@scottalanmiller said in Why the SMB Still Needs Hardware RAID:

The most common RAIN approach that I see is taking all disks in the pool, noting their nodal presence and using mirroring to distribute the data so that data mirrors never go to the same disk and/or the same node. So a little like a networked RAID 1E but with more flexibility and the option to add nodal separation and performance testing so that data moves to where it is used.

Are you aware of any open source RAIN systems?

Gluster and Swift

I think Ceph and Lustre may be two others.

Lustre is RAIN, but is closed. Gluster was the open replacement for Lustre.

Just a quick search showed that Lustre was GPL 2.0, not sure if that is new or not.

Oh wow, must be new. It was crazy expensive in 2006 when we were really investigating it. That's awesome.

Ah looks like it went open source in 2010.

Oh cool, so I remember things well then. I'm just out of date. Gluster probably forced their hand, why would anyone consider Lustre when it was closed source? The answer was probably... they wouldn't and didn't.

Yep, I'd assume that was the case. Especially when it is a such a specific, and at the time, niche market.

And when Gluster went directly after them, even in name.

This is the mobo that this will be connected to:

http://www.supermicro.com/products/motherboard/Xeon1333/5000P/X7DB8.cfm

@Texkonc said in PERC H730P Mini - Multiple LV's:

Dustin

Oh ok

@DustinB3403 said:

Here is the definition.

http://mangolassi.it/topic/6816/hot-swap-vs-blind-swap/2

Now which applies to MDADM RAID? If Cold swapping is the only way of swapping drives, then I guess it immediately excludes it from any Enterprise or even business solution.

MD RAID (MDADM is the management utility for MD RAID) is hot swap, of course, and some vendors like ReadyNAS and Synology add their own extensions to add blind swapping. No one would even discuss it if it wasn't hot swap.

@anonymous said:

Does anyone make a cheap raid card?

Inexpensive raid card no. Inexpensive HBA card, yes.

@scottalanmiller said in What is FakeRAID?:

@Dashrender said in What is FakeRAID?:

Did this pop up again at SW?

Again today, too. Apparently Lenovo is selling FakeRAID on their "servers" now along with all of the other problems. Of course, if a machine has FakeRAID, it's not a server by any normal definition.

WOW... just wow - as if they couldn't fall any further, and they find a way...

i have done this process for one server ya