Raid 0 with SSD?

L

lupo

Weaksauce
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Oct 9, 2005
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I was thinking of replacing the 300Gb RAID 0 boot array I have now with SSD drives. My current drives are 10K and I'm getting easily 300MB/s read/write speed. I'm less concerned with my read/write performance as I am for the almost instant seek time of SSD. (I don't want it do go below what I'm getting now with my mechanical drives, but I don't need 500MB/s or something crazy.) The controller I use now is built into my XPS 720 motherboard and it is a gen1 SATA.

Will SSD work ok in a RAID 0 configuration? Will this cause issues with TRIM support? I am running Windows 7 pro as an OS.

I don't want to spend a ton of money on this either. I could get by with 2 80 or 100GB drives in RAID 0. I really only need it for the OS and applications.

What would you recommend? I currently have a high end highpoint RAID controller in one of my PCI-E slots for my 8TB RAID 5 array for media storage so I would prefer not adding another card as a controller. (The built in raid controller of the MD works great so far for the 10K drives I have now, just don't know if they will play nice with the SSD)

If this will work, which drives would you recommend for great performance around the 80-100GB size?

Feel free to ask me any questions you may have.

Thanks!
 
TRIM currently WILL NOT work with drives in a RAID array. We've all been waiting for about a year now for this to happen and so far no dice. The end result is that you will see a performance degradation in the array (and the drives themselves) over a period of a few months. You can increase that time by creating a RAID0 array that's approximately 80% of the actual total size of the drives, but even then you're just slowing down the eventual degradation in performance. The only way to get the performance back is to do a 'secure erase' on each drive with a utility like HDDErase 3.3.

RAID0 should work fine for you even on a first generation SATA setup. Obviously the throughput isn't going to be as good as what you would see on a SATA2 controller but that's a given.

Basically you just need to be aware that performance will eventually drop and you'll eventually have to back up your stuff, secure erase the drives, and redo everything again.

Or you could just not setup a RAID0 and use your drives singularly - TRIM will work this way and your drives will retain their performance pretty much indefinitely.
 
Wait, I thought it was entirely possible to have TRIM on RAID as long as the controller supports passing TRIM along to SSDs that also support TRIM.

Plus TRIM isn't the only way to fight degradation. Garbage collection works fairly well.
 
So at this point I should just wait until RAID supports TRIM? Although I would rather not add another controller card, do you all know of any that support TRIM?
 
One other thing to keep in mind......

Even at it's worst performance, that RAID0 SSD setup will be so much quicker than a HD setup at it's best, that you'll likely never notice the difference in day to day normal use.

Even a single, non-RAID SSD is going to have better seek times than any rotational HD setup (and also full TRIM support if you're that worried about it.).

I think people tend to get far too hung up on TRIM, and you could very well be waiting into 2011 for official support the way things are (slowly) going.
 
I was thinking of replacing the 300Gb RAID 0 boot array I have now with SSD drives
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I could get by with 2 80 or 100GB drives in RAID 0
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I don't want to spend a ton of money on this either
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How much is a "Ton" of money and what size do you really need?

Either way, there's "Tons" of threads on both. :)
 
Kaldskryke said:
Wait, I thought it was entirely possible to have TRIM on RAID as long as the controller supports passing TRIM along to SSDs that also support TRIM.

Plus TRIM isn't the only way to fight degradation. Garbage collection works fairly well.
Click to expand...

Some drives don't have built in GC in the firmware, such as the intel drives. So the only way to do GC on them is to run the Intel Toolbox Optimizer, but... the toolbox won't work on a RAID array. Catch 22.

And from what I understand GC only works well when the drive isn't filled to near capacity, and even then it's no substitute for TRIM.

And no, TRIM commands are currently not passed to drives that are part of a RAID array. Not in any way, shape, or form.

This confusion should be blamed on a handfull of websites that reported incorrectly on the feature set of the latest set of Intel MSM drivers released back in March or April. These drivers allow TRIM commands to be passed on when the controller is running in RAID mode, but ONLY to drives that ARE NOT part of any array. There is currently no way to pass TRIM commands onto SSDs that are part of a RAID array. :( :(
 
Limahl said:
I think people tend to get far too hung up on TRIM, and you could very well be waiting into 2011 for official support the way things are (slowly) going.
Click to expand...

No kidding. I honestly think we are never going to see TRIM on current generation SSDs when they are part of a RAID array. Otherwise we would have had it by now... There must be something inherent to the drive's operation in RAID that doesn't allow for TRIM commands to actually take place. I'm totally theorizing here but given the amount of time we've waited sofar with no results it makes sense.

I'm betting it's going to require new hardware of some sort... but I'd be oh so happy to be proven wrong!
 
My own solution was to just go ahead and run my two X25-M G2 drives in a RAID0 array, but to take the following suggested measures:

1. Keep about 10-20% dead space on the drives when setting up the array, for instance my ICH10R RAID controller BIOS reported 149.x GB available when I was setting up the array. I told it to use 130GB for the array, thereby assuring that a surplus 20GB would never be touched by the BIOS or operating system. This increases the drive's ability to use it's own wear leveling techniques.

2. Try to do as little writes to the array as possible. The less writes you do the less performance degradation you'll see over the long haul. I loaded my array up with Windows 7, my apps and games, and since I have 8GB RAM I just disabled my page file altogether.

And the poster above me is right - people talk about TRIM way too much. The first generation of SSDs didn't even have any sort of TRIM or garbage collection and the vast majority of owners love them. If/when performance gets below a certain point you just initiate a secure erase of the drive and bammo, there's your performance again.
 
Blue Falcon said:
No kidding. I honestly think we are never going to see TRIM on current generation SSDs when they are part of a RAID array. Otherwise we would have had it by now... There must be something inherent to the drive's operation in RAID that doesn't allow for TRIM commands to actually take place. I'm totally theorizing here but given the amount of time we've waited sofar with no results it makes sense.
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Not really, since TRIM on SSDs in RAID already works on Linux and FreeBSD. With recent kernels, you could have TRIM capability on a limited number of filesystems (Ext4/UFS) but on all RAID stacks (in FreeBSD anything that uses the GEOM I/O framework). I've explained this in more detail somewhere on this forum, let me see if i can find it. :)

No Hardware RAID will likely support TRIM anytime soon, though. This would require firmware changes, perhaps only the better vendors (LSI/Areca) will do this sometime.

If you're looking for Windows support for RAID-TRIM, then i think Intel onboard RAID would likely be the first that would support this; but also Microsoft could be releasing new drivers which make their software RAID stack pass the TRIM command, as well.

So i can relieve some of your worries; it's not inherent to the hardware. Lock up a few nerds in a dark computer room for a week, threatening to kill their pr0n collection, and they will provide you with a TRIM-capable RAID driver.

The problem here is that this would have to be done for each driver; thus Intel RAID, AMD RAID, nVidia RAID, ALi RAID, JMicron, Silicon Image, Adaptec, Promise, etc. All would have to be modified in order to have complete TRIM-on-RAID support. Linux/BSD don't have this problem since they use their own powerful software RAID engine and every module supports passing the TRIM function already. So Windows' support likely will stay incomplete and only some high-profile vendors will in reasonable time implement TRIM on RAID. Intel/Microsoft should be the first, AMD may be next.
 
your only choice for ssd raid is to get a sandforce based drive. there have been a lot of good deals on the 60gb vertex 2 for less then $150, and even the 40gb sandforce drives can be found at $100 market price.

the intel, jmicron, and marvell ssd's do not have any sort of "healing" capabilities for a RAID array and in OSX. the sandforce technology does very well in keeping the drive speedy, especially in raid arrays where TRIM can not be passed.

TRIM is supported when a single ssd drive is configured for RAID, but TRIM can not be passed to a SSD RAID array. What that means is, in the past if you had 1 SSD drive with 2x HDD in raid, trim would not work with the SSD drive (it does now)

The new drivers allow your single SSD set to raid mode to get TRIM, but any raid array of multiple disks will never get TRIM in todays hardware.

Any drives that still use garbage collection are already last generation and should be avoided since the new technology is pretty much the same price.
 
Dumb question, but is the expectation that you are going to notice a difference between a single SSD and RAID 0 SSDs?
 
yes, you will definitely notice it. especially for lupo since his mobo is on sata 150. his drives will be running half speed and limited to 150/meg second. in raid he could get closer to twice that speed.

the new sandforce and marvell drives are pushing the sata 3gbps bandwidth on a single drive. the c300 has noticeable improvements running on sata 6gpbs. so yes, running raid makes things faster.
 
If you only have SATA/150 (1.5Gbps) then you may not have AHCI/NCQ as well, which means much lower random read capabilities; SSDs can do random reads up to 10 times as fast with NCQ present, which requires AHCI.

TRIM is supported when a single ssd drive is configured for RAID, but TRIM can not be passed to a SSD RAID array.
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What you say is correct, but only for the Intel drivers. Any other driver would not pass TRIM if the controller is in RAID mode. Currently TRIM only works with:
- Microsoft IDE driver (pciide.sys)
- Microsoft AHCI driver (msahci.sys)
- Intel 9.6 RST driver (iaStor.sys)

Any other driver, like nVidia/AMD, would NOT pass TRIM in any configuration. So TRIM-support on Windows is limited basically to Intel and Windows' own drivers when not using RAID.

If you install 'chipset drivers' these may also contain storage drivers which cause you to lose TRIM support.
 
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