Author Topic: So, a little story and the power of software RAID  (Read 11809 times)

Offline Brahim

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So, a little story and the power of software RAID
« on: July 31, 2013, 11:45:24 am »
I was browsing Hardforum and stumbled on the thread of a user in quite a pickle: http://hardforum.com/showthread.php?t=1774325

This user is running hardware RAID and is looking to increase the capacity of his array. For that, he is looking to buy drives larger than the ones he is currently running.
As it is typical and required in hardware RAID, upgrading to larger drives means replacing all the existing drives.

One thing that is often not talked about is how users also have to often buy a whole new controller too for the new drives if there is not enough room on the existing controller for the migration.
That or they must fully backup the whole array (to another costly array), remove all the existing drives, put in the new drives, rebuild the new array, and then copy the data back in from backup.

It is amazing that this type of headache (which is both costly and time consuming) is accepted as "the way things are".
Compare that with Transparent RAID where users can use a mix of drives of any size, make, or model.
RAID expansion in Transparent RAID is as easy as adding any drive of any size to the array. Heck, the only drives involved during RAID expansion in tRAID are the parity drive(s) and the new drive being added.
Once you run out of ports, you can buy a cheap card or replace an existing smaller drive with super ease.

It is clear that the only argument one might have in favor of hardware RAID is performance.
That said, Transparent RAID has a trick in its bag that we will reveal soon and that will close that gap. :)

« Last Edit: July 31, 2013, 03:55:50 pm by Brahim »

Offline woodensoul2k

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Re: So, a little story and the power of software RAID
« Reply #1 on: July 31, 2013, 03:27:01 pm »
Very intresting read.  When I first built my FreeNAS array and setup ZFS I did not consider expansion.  ZFS for those who don't know runs just like hardware RAID but using the ZFS filesystem.  It's still not as fast as hardware RAID but it does performs well.  FreeNAS is very picky about hardware.  If I had I would have used FlexRaid from the start.  I will be holding out tRaid but I do know it will be nice to expand one drive at a time.  I currently have a 9 drive system and want to eventually I would expand to 17 but there is no way I can afford to replace 9 2TB drives with 9 or more 4 TB drives and that would be just the start.  Factor into that the risk factor anytime you add just a single drive expand a RAID like that. :o

Almost forgot what would happen if your RAID card took a dump and you could not get the same card anymore, everything gone.  These things are avoided with software RAID and most of us home users don't need or can afford hardware RAID.

If I ever needed the speed and performance of hardware RAID from home I would build a much smaller array dedicated for that task.  On that note I am very interested in what Brahim has in store to close the gap on performance.


Offline Brahim

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Re: So, a little story and the power of software RAID
« Reply #2 on: July 31, 2013, 04:09:12 pm »
I even left out the power consumption aspect too as all those disks are spun and rotated at the same speed continually with the heads kept aligned.
The argument for the longest time has been all this was required for performance.

I think I am about to change that thinking and upset a lot of people in the process. :)
My lips are sealed for now. However, if you were on the fence in regard to Transparent RAID due to speed concerns, I am going to make you rethink everything8)


Offline fishyfish

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Re: So, a little story and the power of software RAID
« Reply #3 on: August 01, 2013, 01:40:18 pm »
I think I have had just about enough of you and your sealed lips, Brahim! ;)

Offline Brahim

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Re: So, a little story and the power of software RAID
« Reply #4 on: August 01, 2013, 02:13:58 pm »
I think I have had just about enough of you and your sealed lips, Brahim! ;)
:-X

Offline jpearn

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Re: So, a little story and the power of software RAID
« Reply #5 on: August 03, 2013, 11:10:41 am »
Could possibly be in the form of caching direct to RAM (like the Buffalo Drivestation DDR) or SSD as a cache, would be neat !

Offline tng2000

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Re: So, a little story and the power of software RAID
« Reply #6 on: August 08, 2013, 12:08:39 am »
However, if you were on the fence in regard to Transparent RAID due to speed concerns, I am going to make you rethink everything8)

Took the words right out of my mouth. I was going to stick with Storage Foundations Basic, but if you have a mechanism to enable good performance then my cash is waiting. Can you give an idea of when this new feature will be made available ? I need to either add more drives to my existing NAS or move to an all new system, of course I would prefer flexibility like tRAID over SFB.

Offline RoderickGI

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Re: So, a little story and the power of software RAID
« Reply #7 on: December 01, 2013, 02:47:35 am »
My lips are sealed for now. However, if you were on the fence in regard to Transparent RAID due to speed concerns, I am going to make you rethink everything8)
I'm still on the fence. It has been four months since you dropped this big hint. Can we know what it was now?

I was going to go with RAID-F until I realised that tRAID only needed to spin up the data drive it was using plus the parity drive(s). I thought initially that it spun all drives at all times like normal hardware RAID.

So I have been reading about tRAID, particularly the bugs reports, problem reports, and performance issues. It is the performance issues that now have me concerned. So, have you revealed the earth shattering new technology that will change the world, and I have missed it, or are you still staying quiet?
Is it in the product yet?
If so, what was it, and how come there still seems to be major performance issues?
If I am wrong about that, and there aren't really any performance issues, where can I find that tested and documented?

It looks like tRAID will be a good solution, but if the write performance is only 25% of the same disk run standalone on Windows, then at the least I am going to have to do some calculations on write speed required for my applications. It would probably pay to do the same for read speeds.

Some answers would be greatly appreciated.