Jump to content
RESET Forums (homeservershow.com)

Software RAID vs. Drive Extender


Dave
 Share

Recommended Posts

I made a comment on 123(i think it was 123) that I wouldn't touch software RAID with a 10' pole. I was asked why privately and thought maybe this is a good topic for conversation. Thinking back to my days of using software RAID I was unhappy with it's performance and overhead. In some way DE is much like software RAID so maybe I should open my mind to using it again.

 

I'm curious as to what you guys think.

Link to comment
Share on other sites

I made a comment on 123(i think it was 123) that I wouldn't touch software RAID with a 10' pole. I was asked why privately and thought maybe this is a good topic for conversation. Thinking back to my days of using software RAID I was unhappy with it's performance and overhead. In some way DE is much like software RAID so maybe I should open my mind to using it again.

 

I'm curious as to what you guys think.

 

I recall the comment, and recall wishing we'd define "software" RAID. I think it was being used reference OS-managed RAID. But Mike (PCDoc) was talking how he didn't like the 96 hour rebuild on his software RAID test, and that was using the onboard RAID.

 

I understand that both onboard and OS managed RAID use the CPU, but there is a difference in how they are managed, and I think we should differentiate between OS managed RAID, onboard (i.e. BIOS) managed RAID, and add-in card RAID. Heck, even most inexpensive add-in card RAID solutions use the CPU to do the management, so why are they not "software" RAID then too?

 

/rant

 

That said, I've had no problems using onboard RAID solutions in 17 years of PC building EXCEPT for when the onboard RAID controller was notoriously poor. That is just as likely with any inexpensive RAID controller card, and I've had issues with all kinds of "true" hardware RAID controllers too.

 

Bottom line for my two cents is the type of RAID control is moot, if the controller is stable.

Link to comment
Share on other sites

I recall the comment, and recall wishing we'd define "software" RAID. I think it was being used reference OS-managed RAID. But Mike (PCDoc) was talking how he didn't like the 96 hour rebuild on his software RAID test, and that was using the onboard RAID.

 

I understand that both onboard and OS managed RAID use the CPU, but there is a difference in how they are managed, and I think we should differentiate between OS managed RAID, onboard (i.e. BIOS) managed RAID, and add-in card RAID. Heck, even most inexpensive add-in card RAID solutions use the CPU to do the management, so why are they not "software" RAID then too?

 

/rant

 

That said, I've had no problems using onboard RAID solutions in 17 years of PC building EXCEPT for when the onboard RAID controller was notoriously poor. That is just as likely with any inexpensive RAID controller card, and I've had issues with all kinds of "true" hardware RAID controllers too.

 

Bottom line for my two cents is the type of RAID control is moot, if the controller is stable.

 

 

Good points. Just to add to this, motherboard controllers are not only slower, but they are not necessarily portable meaning if you change the motherboard or OS, you increase the potential of data loss more so than a dedicated controller add in card. This becomes even more of an issue as you move to larger volumes or a RAID 5 configurations. Having recently in a position that I had to change motherborads, change the OS, I was sure glad I did not loose all the data nor did I have to rebuild the array. Thanks for your comments and good points. I agree that many can and will use the motherboard controller they just may face a slightly higher risk.

Link to comment
Share on other sites

Good points. Just to add to this, motherboard controllers are not only slower, but they are not necessarily portable meaning if you change the motherboard or OS, you increase the potential of data loss more so than a dedicated controller add in card.

I wonder what the technical reasons for that are. Surely the industry can agree on a common format for arrays to allow them to be portable.

Link to comment
Share on other sites

Good points. Just to add to this, motherboard controllers are not only slower, but they are not necessarily portable meaning if you change the motherboard or OS, you increase the potential of data loss more so than a dedicated controller add in card. This becomes even more of an issue as you move to larger volumes or a RAID 5 configurations. Having recently in a position that I had to change motherborads, change the OS, I was sure glad I did not loose all the data nor did I have to rebuild the array. Thanks for your comments and good points. I agree that many can and will use the motherboard controller they just may face a slightly higher risk.

So in comparison to DE in WHSv1, which is also a type of software file duplication that everyone was so up in arms about losing, you would say using motherboard or OS for RAID1 (mirroring) should be fine. That is most similar to DE and has less potential for data loss when something goes wrong. Is this also because, in case of complete server failure, you could take a HDD out and stick it into another PC to retrieve data?

 

However if you use RAID5 with motherboard or OS, while more efficient in its use of storage, means you are basically stuck with it for large volumes unless you find some way to backup the RAID5 array. Which is difficult if greater than 2T because of the backup limitation. In the above example, can you not take a single drive out of the array to be read by another PC? The drive has to have its "controller" in order to read what data is on it?

Link to comment
Share on other sites

I wonder what the technical reasons for that are. Surely the industry can agree on a common format for arrays to allow them to be portable.

 

You know, this has puzzled me. There are "standard" RAID levels, but there's no standard whatsoever about how one is supposed to implement said RAID levels.

Link to comment
Share on other sites

I wonder what the technical reasons for that are. Surely the industry can agree on a common format for arrays to allow them to be portable.

 

 

I have always figured it was due to settings not getting transferred (ie the links are broken). Even if the format is exact, there has to be some data somewhere that tells the system how the array is set up. Without that, how is the new MB supposed to put it back together?

Link to comment
Share on other sites

But where are those settings stored? Within the array? On the drive controllers memory non-volatile memory?

 

 

In my scenario I am assuming it is either on the MB or in the OS and the MB knows where to find it. So if it is on the MB, and you put a new one in, then it won't work. This is my non-expert idea. About three or four years ago, a freind and I tested with two MB's that were exactly the same, even the firmware. We swapped them and the array was lost.

Link to comment
Share on other sites

Given the title...

 

Raid in any flavor vs DE is better in some ways, worse in others. DE like many things MS was focused on making it easy for non techs to manage their storage needs, but less desireable in areas that would appeal to business, and I believe this is the consensus as to why DE was dropped... it was not business friendly.

 

From a WHS perspective I believe this makes the product much more niche than before with it mainly appealing to enthusiasts, those who will benefit from promoting 2011 in some way or those wanting to run enterprise services on WHS for some reason (this still baffles me because you have 2008 R2 out there that would most likely do these things better).

 

From a non-techie perspective I thought my brother (a non tech machinist) summed it up best when I was trying to explain all this to him. 1st he asked, isn’t this raid things what you were using on your file server like 10 years ago? I said yes. He said removing DE was like if Ford decided to not provide tires and changed the axels to only allow wooden wheels and called it an improvement, even if wooden wheels are great this means I now not only do I have to buy the tires, but I have to use old tire technology to boot.

 

Judging from the reaction of poeple I have tried to explain this to I really hope the OEMS come up with some nice solutions because I do not want to see the platform die and these DE add-ins coming out will not save the day in time, neither will raid or any amount of cheerleading a technology that has been around a very long time and has never made on ounce of impact in the consumer market.

Edited by talex
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...