Hardware vs software raid?

[Docretier]

Would you guys recommend a dedicated raid card over a windows based raid? I know windows is prone to not working like it’s supposed to, so that’s why I am leaning more towards buying a card. If you recommend hardware raid, could you link me to some good raid controller cards then? 

[Uptivuptiz]

This Quora article explains it pretty well.

[jde3]

There is no such thing as hardware raid. There is SOC Firmware Raid and OS Raid. *ALL* of it is software. Do you want that software to be managed checked and maintained by your OS provider or by ??? other.. people.. who may or may not still be employed by a company that hasn't been acquired by someone.

 

@Uptivuptiz Sorry man, your article sucks.

Advantages of Hardware RAID

• CPU utilization and performance when other applications running. That is the host CPU need not to worry about the raid array.

CPU's are so fast today vs how fast IO is.. really? Your CPU is 1000x times faster than the drives.. it can handle the load.

• Scalability of disk drives that can be added to a system.

True but HBA/Sata extenders exist.

• Ease of recovery after a data loss.

No.. just no.. if you have ever needed a speific version of the array's firmware to access the drives from another working array but were unable to get that version of the firmware because the vendor removed it from their website.. you know know just how "easy" this recovery will be.

• Capability for advanced data management/monitoring.

And operating systems do not have this?

• Ability to manage disk drives consistently across different operating systems.

*IF* they have drivers for the array controller and are supported by it. You'll see "Oh we support Linux. The 2.4 kernel" or "Yeah we support FreeBSD, FreeBSD 8".

• We can add battery backup option that allow to enable write caching on the RAID controllers to enhance write performance of the system.

So in this way you can lie to the OS and tell it something was finished writing to disk when really it was written to cache. OS's can do cache too and they do them from system ram that is extremely fast.

 

None of the disadvantages they list for software raid exist with ZFS. It has no fstab or raidtab or any other config file that sits on the OS and it can be read by different operating systems. It does do cache because it has transnational and reordered writes etc etc etc.

 

Old bad info.

[Razor Blade]

A few use cases for hardware RAID would be 

 

1. If you wish to offload the disk management to a controller for any reason. Useful if you end up using multiple operating systems on a single box that doesn't have a hypervisor (such as a windows and linux dual boot system) or maybe have an OS or hypervisor that doesn't have RAID as a disk management option.
2. If you wish to put your OS onto an array. For example if you have an OS on a RAID 1 so if a disk dies, your OS remains unaffected. You pop in a new disk and your controller takes care of rebuilding the array.

Otherwise an OS that can manage many disks into an array is the way to go. Many times you have the option to manage and maintain an array much more so than a hardware solution will do and many times will have more versatility.

 

One thing I would advise is to stay away from using built in motherboard RAID controllers. I've never been impressed with their performance and if there was ever a problem, recovery would be more difficult as it isn't just as simple as replacing the card and importing the foreign array. I would also advise if you get a RAID card with cache capability make sure you get a battery for it because many cards will disable the cache function if you don't have one installed.

[jde3]

To #2 if whatever your using for a OS can't drive on after a single disk crash or boot off a degraded raid1, then your using something bad. What is the point if it's unrecoverable by just replacing (hot swap) the drive? And no.. all OS's do not have this problem.

[Razor Blade]

1 minute ago, jde3 said:

To #2 if whatever your using for a OS can't drive on after a single disk crash or boot off a degraded raid1, then your using something bad. What is the point if it's unrecoverable by just replacing (hot swap) the drive?

That is the point. If your OS is on a RAID 1 array any OS will "drive on" completely unaffected. You just replace the failed disk and the controller takes care of rebuilding the array. This isn't a substitution for backups it is a tool to keep the OS running even if a disk fails.

[jde3]

31 minutes ago, Razor Blade said:

That is the point. If your OS is on a RAID 1 array any OS will "drive on" completely unaffected. You just replace the failed disk and the controller takes care of rebuilding the array. This isn't a substitution for backups it is a tool to keep the OS running even if a disk fails.

I don't understand what your talking about, why can't this be done with a software raid? I do it all the time. Sometimes I intentionally fail a drive to make a clone. Is this some strange btrfs nonsense? What good would an OS raid be if it couldn't do this?

[Razor Blade]

17 minutes ago, jde3 said:

I don't understand what your talking about, why can't this be done with a software raid? I do it all the time. Sometime I intentionally fail a drive to make a clone.

You have an OS installed on a RAID array managed by the same OS? I'm talking about your operating system being installed on a RAID 1 array. Not an array created by the OS.

[jde3]

8 minutes ago, Razor Blade said:

You have an OS installed on a RAID array managed by the same OS? I'm talking about your operating system being installed on a RAID 1 array. Not an array created by the OS.

Of course I do. Why is this special?

 

# zpool status
  pool: tank
 state: ONLINE
  scan: none requested
config:

           NAME        STATE     READ WRITE CKSUM
        tank          ONLINE     0     0     0
          mirror-0  ONLINE     0     0     0
            dm-0     ONLINE     0     0     0
            dm-1     ONLINE     0     0     0

errors: No known data errors

 

I've done this with other things too mdadm etc.

[leadeater]

9 minutes ago, jde3 said:

Of course I do. Why is this special?

Because Windows can't do that .

[jde3]

13 minutes ago, leadeater said:

Because Windows can't do that .

I may have done this on windows.. not sure.. you have to trick it? can't remember.. windows.. bah who cares.. it's like running android on a raid. lol My Windows advice is: Don't put real data on a windows device and have a backed up copy of everything it does because it could die any second.

 

Really? It can't? Learn something new every day.

 

I've had my system OS on raid1 for so long.. hell ~15 years now?

[Razor Blade]

12 minutes ago, jde3 said:

Of course I do. Why is this special?

Did I say it was special? I missed that part.

 

If you have something like Windows 7 or higher you could use dynamic disk and create a mirror. But then again... you're relying on disk management of Windows...

[leadeater]

27 minutes ago, jde3 said:

I may have done this on windows.. not sure.. you have to trick it? can't remember.. windows.. bah who cares.. it's like running android on a raid. lol My Windows advice is: Don't put real data on a windows device and have a backed up copy of everything it does because it could die any second.

 

Really? It can't? Learn something new every day.

 

I've had my system OS on raid1 for so long.. hell ~15 years now?

Windows can't do software RAID for the OS drive, have to use onboard/chipset RAID or a RAID card for that. Linux of course can use software RAID for OS.

[jde3]

2 minutes ago, leadeater said:

Windows can't do software RAID for the OS drive, have to use onboard/chipset RAID or a RAID card for that. Linux of course can use software RAID for OS.

Weird.. Microsoft must have been too busy improving Cortana's "experience" rather than adding basic OS functionality.

[leadeater]

Just now, jde3 said:

Weird.. Microsoft must have been too busy improving Cortana's "experience" rather than adding basic OS functionality.

"Hey Cortana, please boot off software RAID"

Cortana: "I don't know how to do that"

[jde3]

1 minute ago, leadeater said:

"Hey Cortana, please boot off software RAID"

Cortana: "I don't know how to do that"

What? That isn't helpful enough for you?

[Razor Blade]

Addressing what your adding to your posts

1 hour ago, jde3 said:

*snip*

Is this some strange btrfs nonsense? What good would an OS raid be if it couldn't do this?

No it isn't. It is a very simple concept and I don't know why you're getting so bent out of shape.

43 minutes ago, jde3 said:

I may have done this on windows.. not sure.. you have to trick it? can't remember.. windows.. bah who cares.. it's like running android on a raid. lol My Windows advice is: Don't put real data on a windows device and have a backed up copy of everything it does because it could die any second.

*snip*

Addressed this already. RAID is not a substitution for a backup. Yes you can convert your boot disk to a dynamic disk and create a mirror array after windows is installed. But again...disk manager... The use case I have in particular is my VM datastore on my ESXI box is on RAID 1. ESXI doesn't support software RAID so I would either have to use another OS to manage a software raid and use iSCSI or just use a RAID card. I chose the simpler solution.

 

 

 

I don't know what your problem is but I never said hardware RAID was superior. Yet you act like I did. I actually prefer software RAID if you would actually read what I wrote. 

Edited September 6, 2018 by Razor Blade
fixed format deleted misunderstood quote

[jde3]

5 minutes ago, Razor Blade said:

52 minutes ago, jde3 said:

*snip*

I've done this with other things too mdadm etc.

I would appreciate if you would be civil.

HA... hehehehe.. oh this thread.

 

Nice one man... ok mdadm is Linux's in kernel md admin (raid config) tool.

 

I think you are taking thing out of context here man, You're just fine with me.. I just didn't know what you were talking about is all.

[Razor Blade]

2 minutes ago, jde3 said:

HA... hehehehe.. oh this thread.

 

Nice one man... ok madam is Linux's in kernel md (raid config) tool.

 

I think you are taking thing out of context here man, You're just fine with me.. I just didn't know what you were talking about is all.

I misread it, my mistake I fixed the post. I realized you were talking about the linux tool after I hit submit reply 

[Sauron]

ZFS is where it's at, all the cool kids use it