When will TRIM support for RAID be available?

D

djlenoir

Limp Gawd
Joined
Mar 15, 2002
Messages
373
So I got into the Velociraptor versus SSD debate recently and decided that I would just abstain from deciding which is best and just bought two of each to set up in a RAID0 configuration. Well, I went to set it up last night and decided I better search for the correct stripe size for SSDs in a RAID and found out that TRIM is not supported in a RAID configuration. Well, that blows. Now I am not sure I want to even RAID them anymore. I don't want a super speedy RAID array that runs slow after breaking it in a bit. So is the consensus around here to RAID or not to RAID (that is the question)? :p Is TRIM something that driver makers handle and decide for us that they are too expensive for us to afford more than one so we don't need that feature right now? Or is it just not available due to the nature of RAID?

The drives are OCZ Vertex 2 120GB 3.5" drives by the way. I also bought two 300GB WD Raptors that I still plan on putting in RAID0.
 
Or is it just not available due to the nature of RAID?
Click to expand...

I believe this is the reason. Its more difficult to do this under raid. Although raid 0 should be the easiest raid level to add support.
 
From what I've read from various SSD makers(might be some bias here though), there's nothing that's stopping TRIM on RAID arrays other than controller companies not putting in the time to create a driver that will pass the command. I guess the hard part would be determining which drive held that data that was deleted and needs the command, but it should be something that can be worked around.

OP, your drives support garbage collection. That means when there is enough idle time(like at the log-on screen or even the BIOS screen) the drive will perform something like TRIM. It's not as good as TRIM since it's not immediately, but it should keep the drives from experiencing major slowdown over time.
 
TRIM is supported in Intel RAID:
http://techreport.com/discussions.x/18653

EDIT: Burner27 below is correct, had also read: http://www.bit-tech.net/news/hardware/2010/03/23/intel-releases-trim-for-raid/1

Which made it look like it was supported, but its not.

From the site:
"Thankfully, Intel has solved the problem with the release of a TRIM-compatible driver which finally brings the technology to SSDs in RAID arrays. Available over on Intel's website – via TechConnect Magazine – the new Rapid Storage Technology driver allows users of selected Intel motherboards to enjoy the benefits of RAID without losing the benefits of TRIM support. There are caveats to the driver, of course: your operating system needs in-built TRIM support, and all drives in the array must be TRIM-compatible. You're also out of luck if you're running RAID 5, for some reason – although the home-use scenarios of RAID 0 or RAID 1 are well covered."
 
Last edited:
war9200 said:
TRIM is supported in Intel RAID:
http://techreport.com/discussions.x/18653
Click to expand...


Might want to read the article fully. You are misleading the OP.

From article:

Translation: if your Intel storage controller is set to RAID mode, you'll now be able to benefit from your solid-state drive's TRIM functionality when running it alongside a RAID array comprised of mechanical drives. TRIM isn't supported for SSDs participating in a RAID array, however. Intel may add that feature in the future, but it hasn't committed to doing so.
 
Trim is only supported on non member disks under the Intel driver.

As I recall a while back computurd asked Areca about trim and RAID and the response they gave was that trim isn't even part of the SAS spec so until that get's integrated there will never be trim for RAID controllers with maybe the exception of Intel/AMD chipsets.
 
S-F said:
Trim is only supported on non member disks under the Intel driver.

As I recall a while back computurd asked Areca about trim and RAID and the response they gave was that trim isn't even part of the SAS spec so until that get's integrated there will never be trim for RAID controllers with maybe the exception of Intel/AMD chipsets.
Click to expand...

At the bottom of the URL I pasted (bit-tech), there is an e-mail back from Areca:

Just got this recently:

Sent: Sunday, April 18, 2010 3:15 AM
Subject: Ask a Question

> Category : PCIe/PCI-X RAID controller
> Model name : ARC-1680IX-12-4G
> Firmware Version : 1.48
> Disk Vendor : Intel
> Disk model : SSDSA2MH160G2R5
> Operating System : Seven Ultimate 64bit
> Driver Version : V6.20.00.19_91126_W7WHQL
> Motherboard Vendor : Tyan
> Motherboard Model name : S7025AGM2NR
> Motherboard BIOS Version : 1.05
> Your Question : When will drivers support TRIM for SSDs?


Dear Sir/Madam,

The TRIM command specification is being standardized as part of the ATA interface standard.
OS use the build-in ATA command device driver to communicate the ATA port for TRIM command. But most of the RAID adapter emulate the

SCSI command to support more volumes on one RAID adapter, including our RAID cards. this command different result the TRIM command can not support on all vendors of RAID adapters.


Best Regards,


Kevin Wang
 
So "is being standardized as part of the ATA interface standard" is the key phrase, not ready yet.
 
war9200 said:
TRIM is supported in Intel RAID:
http://techreport.com/discussions.x/18653

EDIT: Burner27 below is correct, had also read: http://www.bit-tech.net/news/hardware/2010/03/23/intel-releases-trim-for-raid/1

Which made it look like it was supported, but its not.

From the site:
"Thankfully, Intel has solved the problem with the release of a TRIM-compatible driver which finally brings the technology to SSDs in RAID arrays. Available over on Intel's website – via TechConnect Magazine – the new Rapid Storage Technology driver allows users of selected Intel motherboards to enjoy the benefits of RAID without losing the benefits of TRIM support. There are caveats to the driver, of course: your operating system needs in-built TRIM support, and all drives in the array must be TRIM-compatible. You're also out of luck if you're running RAID 5, for some reason – although the home-use scenarios of RAID 0 or RAID 1 are well covered."
Click to expand...

WAR9200-

You are also quoting another article written 1 day later than the original article you linked--they too have the wrong information. TRIM is NOT supported on any drive configured in a RAID array. Your controller can be in RAID mode, and it will pass the TRIM command to all drives that are 'non-member disks' but not to any drives in a RAID array.
 
So in general computer use, would I see more benefit from using the two SSDs individually, with say OS and applications on one and games on the other with TRIM support on both under Windows 7, or would I see a bigger benefit creating a RAID0 out of them? I don't code anymore and video work for me involves "archiving" movies and re-encoding them to fit the format of some of our portable devices. The most demanding thing I do with my computer is run a half dozen systems in my vmware lab to test stuff for work purposes. Besides that it is checking email, everything web related and gaming.
 
djlenoir said:
So in general computer use, would I see more benefit from using the two SSDs individually, with say OS and applications on one and games on the other with TRIM support on both under Windows 7, or would I see a bigger benefit creating a RAID0 out of them? I don't code anymore and video work for me involves "archiving" movies and re-encoding them to fit the format of some of our portable devices. The most demanding thing I do with my computer is run a half dozen systems in my vmware lab to test stuff for work purposes. Besides that it is checking email, everything web related and gaming.
Click to expand...

I was debating this exact same scenario. I have 2 x 80GB Intel G2s in a RAID 0 format and although I can 'feel' a slight performance gain over a single drive setup....I feel that the space I am wasting (using ~29GB on a 111GB RAID array) could be better utilized having the drives separated.

Currently, i am going to see if i can go back to AHCI mode without having to reinstall the OS and apps......
 
Currently, i am going to see if i can go back to AHCI mode without having to reinstall the OS and apps......
Click to expand...

the only way to do this would be to take a snapshot of the RAID and then apply that image to another disk. there is no way to break the RAID without destroying the data.

TRIM is not supported on RAID member disks because that would require each SSD's controller (which manages TRIM) to communicate with the other drives in the array in order to know what blocks to TRIM and what blocks are part of the file system. TRIM works on single drives because the entire filesystem is located on the single drive, and is entirely accessible to the SSD controller. RAID controllers do not have any way of coordinating TRIM information between multiple drives.

when TRIM is not avaible, other garbage collection routeins are implimented, but differ between different manufacturers and models and controllers. some are better then others. some people with SSDs in a RAID never miss TRIM and never notice much of a slowdown over time. people who intensely write to the drive all the time might notice it more.
 
ghost6303 said:
when TRIM is not avaible, other garbage collection routeins are implimented, but differ between different manufacturers and models and controllers. some are better then others. some people with SSDs in a RAID never miss TRIM and never notice much of a slowdown over time. people who intensely write to the drive all the time might notice it more.
Click to expand...

Any specific examples of a particular MFG and model that works well when no TRIM availability?

Reason I ask is I'm thinking of picking up 2 SSD's to run in RAID0 config for OS only. Due to monetary/financing constraints I'm looking at Intel X-25 V's in a RAID0 over a single/standalone SSD (X25-M, or Corsair F120).

I'm still using XP Pro (SP3), and thought I'd have to flip to Win 7 for TRIM, but if that's not truly necessary, then it'll save me the $$ of having to migrate to a Win 7 OS.
 
Intel works better on XP (better on misaligned I/O) but also degrades faster in RAID; it only has 6.8% spare space. You may want to use overprovisioning and give the SSDs more spare space if you going to run Intel SSDs in RAID without TRIM capability.

On topic: i believe the problem is RAID controllers under Windows act as SCSI controllers, and as such the SCSI command set is used. This does have a TRIM command, but it works differently and is not the same as ATA TRIM command; thus SCSI would need a new command to make this possible.
 
Any specific examples of a particular MFG and model that works well when no TRIM availability?
Click to expand...
None.

Just get a single 80GB Intel and be done with it.

RAID0 on the crippled Vs would be more trouble than it's worth.
 
You must log in or register to reply here.
Back
Top