RAID for Rookies

[tinytomlogan]

New boy Matt joins the OC3D team and his first article is a Raid Guide. He says "It is time to dispel the mystique around the previously perceived 'hardcore' hard-drive setups..."




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[Josh Weston]

A great write-up.
Welcome to the team, Matt.

 

[Spaceboy]

Impressive write-up there

However, as an ex-storage consultant, please permit me to point out a few niggles

Page 2 - Raid 5 : You mention "Instead of the traditional mirroring of stripes"... I believe this should read "striping of mirrors" as you aptly described in the Raid 1+0 section above. Remember that striping of mirrors offers greater redundancy than mirroring of stripes (raid 1+0 is better than 0+1).

Page 2 - Raid 6 : The parity is not mirrored, it should be (in any decent implementation) a completely separate parity generation - this offers extra protection against bad blocks that store Raid-5 parity data during rebuild operations.

Page 3 - Mirroring : This attribute offers substantial performance gains for read operations, but none for write operations.

Page 3 - Raid FAQ 1 : Performance improvements are in-line with hard drives, eg: Raid-0 across 2 SSDs will double the throughput in both read and write operations. While real-life improvements may barely be noticeable, the performance increase is real. Also TRIM is now supported in Raid-1, so I argue that wear-rates are not substantially increased over a single SSD. I do agree it rarely makes financial sense though

Raid FAQ 3 : It is very possible to partition your different size drives and then use software RAID across like-size partitions. Leaving you with free partitions you can use for data storage, with the proviso they have no redundancy. Eg: 2TB + 500gb - partition the 2TB into 1.5TB + .5TB, then RAID across the 500gb partition and the 500gb drive. You can subsequently use the 1.5TB partition as normal.


I fully approve of the work you've put in to this and it is overall very good
I am however anally retentive having done this for a living for a while so I hope you'll take my comments as "constructive criticism" rather than any kind of dig

Keep up the good work!

 

[f00f1ght0r]

Thank you kindly folks for the welcome!

Spaceboy - i'm honestly impossible to offend, so don't worry about that. The article was aimed at beginners, so my intention was lay some basic phrases and general understanding in this article, and then 'polish it up' in future advanced articles.
I do bow to your knowledge on this subject though, I am but a Jack of All, Master of None, based on the comparison between our job roles!

 

[Noz_God]

Nice wright up

 

[Diablo]

Good work, I will agree with the RAID 5 comments - I tried a software/onboard method, and got a 5-6MBps throughput, when I upgraded to a dedicated RAID card (adaptec), that went up to over 200MBps.

 

[ugiboy]

Raid0 on SSD's

Hi, very impressive & informative article, well done Matt, I look forward to the follow ups. If I have understood this correctly (which is doubtful) putting SSD's into Raid0 array has no performance benefits & speeds up degradation? I look forward to anyones opinions/thoughts. Cheers

 

[tinytomlogan]

Hi, very impressive & informative article, well done Matt, I look forward to the follow ups. If I have understood this correctly (which is doubtful) putting SSD's into Raid0 array has no performance benefits & speeds up degradation? I look forward to anyones opinions/thoughts. Cheers

Yeah you have not got the grasp of it at all..... LOL

 

[ugiboy]

I thought as much lol

 

[ugiboy]

My understanding this review?

Beginner RAID FAQs
Q: Can I use Solid-state drives for a super-fast array?A: Yes and no... SATA3 and PCI-E SSDs are already ridiculously fast - RAIDing them will either present negligible performance improvement (for RAID0), or in the case of the mirroring and parity RAIDs, will greatly increase the wear rate of the SSDs, therefore reducing their lifespan. So it *is* possible, but it does not make financial sense in my honest opinion!


Tom, I have taken this from the FAQ section of the review. So can you explain what i have not grasped please. Cheers

 

[tinytomlogan]

Beginner RAID FAQs
Q: Can I use Solid-state drives for a super-fast array?A: Yes and no... SATA3 and PCI-E SSDs are already ridiculously fast - RAIDing them will either present negligible performance improvement (for RAID0), or in the case of the mirroring and parity RAIDs, will greatly increase the wear rate of the SSDs, therefore reducing their lifespan. So it *is* possible, but it does not make financial sense in my honest opinion!


Tom, I have taken this from the FAQ section of the review. So can you explain what i have not grasped please. Cheers

You said about raid 0- that does make them a shit load faster even with onboard raid or software raid. The statement about degradation with other arrays is correct though but no different to intensive use.

Ive got 2x 480GB Corsair Force 3 GT's in Orca in Raid0 - read and write on the arrany is over 1GB/s

 

[ugiboy]

OK, thanks, I will run crystal disk to find out how my 2x120gb fair. I know my Ramdisk is about 8100mb read & write. Cheers

 

[tinytomlogan]

Just need to remember TRIM does not function with RAID so you need to make sure your SSD's have hardware level garbage collection or they will in no time at all run like dogs.

 

[ugiboy]

Thanks for that, will check it out. Cheers

 

[Soda-88]

RAID0 TRIM is supported by Intel's 6 and 7 series chipsets.
http://www.anandtech.com/show/6477/trim-raid0-ssd-arrays-work-with-intel-6series-motherboards-too

 

[f00f1ght0r]

RAID0 TRIM is supported by Intel's 6 and 7 series chipsets.
http://www.anandtech.com/show/6477/trim-raid0-ssd-arrays-work-with-intel-6series-motherboards-too

My personal thoughts are that in a 'beginners' article, we do not want to get into BIOS flashes, let alone Hex Editing live drives. This would, however, be ideal in the area at the bottom of the final page where I mentioned about going into things with greater depth

 

[seumasbeathan]

Great write-up mate I look forward yo reading more in the future

And welcome

 

[ugiboy]

My Asrock X79 extreme11 says it supports trim but i do not know how to enable or even check if it is running? any members have any idea to i could do this please.

 

[f00f1ght0r]

ugiboy - I haven't followed the research to the end of the internet looking into your system, but it appears to revolve around flashing the BIOS and, you guessed it, editing live file system hex.

It may support TRIM, but that is simply on separate SSDs, not on RAID perhaps?

On the official page for your mobo, it mentions RAID0, not RAID5 - speed is obtainable, but the lifespan and speed of the drive/s may be compromised without TRIM/hardware controlled garbage collection.

Microsoft advise that you can verify TRIM being active (not just able to be supported) through these steps:

1. Start Menu > Run > "fsutil behavior query DisableDeleteNotify"
If the result is '0' TRIM is available (not necessarily active)

2. Install and run Intel's SSD Toolbox program (http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=18455)

3. Select your SSD and click "View Drive Information" (it doesn't matter whether it's an Intel SSD or some other brand)

4. In the "Word" column, scroll down to '169'; the description should be, "Data Set Management Support"

5. A couple of lines down from that, look for "Bit 0 - Data Set Management Supported"

6.If the Hex Value associated with that reads '1', the drive is ready to receive TRIM commands from the OS

That, along with the 'fsutil' command, should be sufficient to assume that TRIM is operating properly.

 

[ugiboy]

Hi, thank you for taking the time to reply and for the instructions. I have Intel's SSD Toolbox V3.1.2 and when i click the "View Drive Information" nothing happens? I will download it again to see if it works and hopefully follow your instructions. Thanks again Glen Hi, I have entered what you said in "command prompt" and it is telling me DisableDeleteNotify = 0. If i understand you correctly that means that "Trim" is enabled? Thanks Glen