RAID- What the heck is it?

So Looking at 151EM's i see there's an option for RAID 0 and Raid 1, I was hoping someone could fill me on on what exactly RAID is and what it does? Improved performance? Improved read/writes?

If this were reddit I'd be posting under "Explainlikeimfive" Anyways any insight would be much appreciated!

 

RAID simply stands for Redundant Array of Independant Disks. There are many RAID "levels', denoted by a number. RAID 0 for example, requires two identical hard drive disks. They are "striped"- that is to say, the controller basically makes one logical disk out of two physical ones so that you can get 2x the performance and space of a single disk. RAID 1 on the other hand goes for redundancy rather than performance. It takes the same two drives but creates a full mirror of the first drive on the second. If a drive in RAID 0 fails, you lose all of your data since it was shared over two drives. If a drive in RAID 1 fails, you don't lose anything since you had a backup drive. There are a few other "standard" RAID levels, but they aren't usually seen on laptops.

You can get a good rundown on wikipedia:

Standard RAID levels - Wikipedia, the free encyclopedia

 

Yup, the wikipedia page is fascinating. I spent a whole day reading it last summer. True story, but then again, I'm a huge math nerd. It's impossible to explain without charts and graphs and stuff, so I won't bother trying to summarize it.

 

Obligatory: RAID IS NOT BACKUP!

Repeat: RAID IS NOT BACKUP!

It's good to have a redundancy, but if you have a file that you accidentally deleted and want back, RAID 1 is not going to help you.

 

a gross simplification is as follows:
[using the same size drive]

Raid 1: uses two drives and your computer reads it as one drive, this is beneficial because if one drive fails, it can be rebuilt by the other drive. there is no read or write benefit with this raid array.
ex: 500gb + 500gb = a VERY safe 500gb

Raid 0: uses two drives simultaneously to read and write the same data onto two drives, separating the files into parts. This raid array provides you with 50-99% better read and write speeds because both drives are working to read/write the same data. The DOWNSIDE to this array is that should one drive fail, you will LOSE ALL your data, and it can't be rebuilt.
ex: 500gb + 500gb = 1tb with faster read and write capabilities

if you decide to go raid 0, be sure to keep back ups.

happy hunting

 

As a matter of fact most people usually pick RAID 0 for best possible performance, especially if you've got two solid SSD's

 

Using any kind of RAID with SSDs is still not advisable. TRIM doesnt work in RAID yet (TRIM support in RAID has been promised a while ago but it is still nowhere in sight) so performance will degrade with use. Sadly the idle GC with most SSDs is garbage and doesnt help much. Keep that in mind. Not saying people dont do it (and that i havent thought about it myself) but expect performance degradation over time.

 

The rumor is the Intel 11.x RST drivers will contain TRIM support for SSDs in RAID-0. I'm guessing that this might cover RAID-1, but have no idea what this means for RAID-5 or RAID 1+0 (10).

There are "alpha" level drivers available, and some have posted links somewhere on notebook review (I'm sure a search can uncover them), with a supposed summer release. However, note the last day of summer is sometime late Sept.

 

Theres also the matter of Bios support, not just the driver as im told. Clevo might or might not implement it.

 

That is most likely incorrect. If you find those links I mentioned, you'll find those that have it installed against their existing BIOS are not having any problems.

 

Thats what i was told at least by someone working on TRIM in RAID on Clevo machines - that its not just the RST driver component that needs to support it but also needs proper Bios support to communicate it through.

 

I rather invest in one nice SSD, keep backups as normal.

 

Hmmm... I do believe in one of those links the user had a Clevo/Sager, but am not 100%.

If it *does require a a BIOS change, then most likely it would be tied to the RAID portion of the BIOS. Perhaps RAID-0/1 work, but if you go with RAID-5, a BIOS update would be req'd? It seems odd that the alpha drivers are working for some people in RAID-0.

 

Link to whoever has it working please.

 

Sorry, too lazy to find all of them. As I stated earlier... "If you find those links I mentioned, you'll find those that have it installed against their existing BIOS are not having any problems."

You can search these forums by the search or w/ a search engine. A quick search found this thread - http://forum.notebookreview.com/har...ades/625315-exciting-news-all-raid0-fans.html Perhaps you can check w/ Dufus to see how its working out.

 

Not to talk about useless (in some degree) the speeds you get are beyond absurd, no need for that, well not for the common user with way too many money on his hands.. it's a illusion of performance one creates for himself

but TRIM would be nice.. it's been promised quite a while now

 

Ah i think you got confused by the false reports back then when TRIM support was announced to be released in 11.5 RST drivers. When those leaked alpha ones showed up people though they had TRIM but infact it turned out it wasnt implemented in them yet. I havent found one credible evidence of TRIM working in any RAID config.
Id be glad to be wrong, so if you have anything do show us.

 

Sorry, I misread Dufus' post this time around (but didn't in the original thread) - see page 3.

In any case, I posted to that thread asking an update. We'll see if anything's been leaked.

 

Here's someone seems to be using it as well - http://forum.notebookreview.com/sol...ge/631570-where-rst-11-5-a-2.html#post8530854

Everyone seems to be working on these drivers, and no mention of anything BIOS related. For all I know, all it could be is AHCI/RAID be support in your BIOS - which should be true in all the Clevo lappies which are RAID capable in the last 24 or so months.