what is sata raid?

Just a shot question: What is sata raid?

 

A raid using SATA drives.

 

Have a read here it will tell you all you ever need to know about RAID

 

Serail ATA interface in a redundant array of independent disks/drives. Basically where more then one drive s combined into one volume or into mirrors of each other. Basically it helps combine drives into a large single volume with a much better file system (striped), and or allows for a drive to fail and the other to pick up where the other left off. Basically a back up drive. (mirrored)

Read the article for more info.

 

quite simply it is the hardware setup of having two or more Hard Drives, each running and storing exactly the same data. The advantage of having RAID is that if you have cruucial documents and files, if one Hard Drives fails, another one kicks in back into action. That is basic RAID 0. Raid 1 and so on get more complicated.

SATA is the new generation of IDE (also called Parallel ATA). It is simply the connection on the motherboard which connects a Hard Drive to the motherboard. The advatage over a SATA connection to a PATA connection is that it offers far better transter rates.

 

Actually i'm afraid your wrong, (what your reffering to is RAID 1) Raid 1 is where you have two disks both copies of each other, so if one fails - then the other takes over. Raid 0 is when you stripe the information over 2 disks - so that it increases random access times - but this does not increase reliability - infact it decreases it since if either of the two disks fail then you will be unable to access any of your data.

Read the link i gave.

 

Raid 0 is rather useless then. It is rather silly to have the RAID 0 system.

 

well no, because it is used to increase the speed of accessing data.

But in terms of data protection - then yes it is useless.

 

SATA and PATA are not the same thing nor are the drives interchangeable. A SATA hard drive wil not work in laptop with a PATA a.k.a UATA or ATA/100 interface. Saying they are the same is misleading.

 

Okay thanks for the info. So correct me if i'm wrong: If i put a 2nd harddisk in my laptop i can use Raid else i can't use Raid.

 

Just to add, SATA drives don't automatically increase your transfer rates. One advantage of a SATA drive is simpler cables and it takes less CPU usage to access data off the drives.

RAID 0 is called data striping - two identical hard drives are essentially seen as one by the system, and the data is 'striped' across both drives. It can really increase your transfer rates, but often it isn't much faster than a single drive (less than five percent faster sometimes). Also, the risk of data loss is high.
An example of RAID 0 - if you put two 320GB 7200RPM hard drives in a RAID 0 config, you end up with a 640GB (formatted capacity is less of course), 14400RPM drive.

RAID 1 is mirrored data - two drives with the same data. There's a very slight hit in performance but nothing major.

 

No your pc must have a raid controller to work in raid. Most laptops dont have raid controllers, in fact I think only a few can support raid setups; and they are very high end laptops if Im correct. The advantage to having a raid 0 or stripped volume is space is used ALOT more eficient. The drives stripped dont follow the NTFS 4kb cluster size; rather they store data per the space it actually requires without a waste. That and it also combines 2 drives into one allowing databases to be easier to manage; having 1 volume instead of many. It has its advantages and disadvantages. For most its useless but for system admins like my self a mirrored scsi setup saves my tail when a drive fails I still have a working server.

 

Just to be pedantic, that's precisely what you don't end up with. A 14400 RPM drive would have insanely good seek times (because the platter rotates so fast, no matter where on it the data you're after is located, it'll end up under the read head in no time)

Instead, you get... 2 7200 RPM drives.
So they still have to wait for a 7200RPM platter to rotate, and locating data becomes slightly slower. But once it's located and the read heads are in position, it can transfer twice the amount of data per second. Because it's reading from two drives.

A 14400 RPM drive would give you ~100% performance improvement, whereas RAID 0 typically gives you maybe 10 percent.

True. I might add that the performance hit is pretty much theoretical only. It's not something you'll notice. A more important downside is the obvious one that if both drives contain the same data... everything takes up twice as much data. So two 300GB drives will only give you 300GB disk space.

 

That's correct. Can you use an external HDD as the second HDD for setting up RAID 1?

 

Generally, that's what I have seen it referred to as - double the RPM. I wasn't implying that you got the performance of a 14,400RPM drive, just so we're clear.

 

If i do want to choose between raid0 and raid1, must i do this in the bios? I ask it because my bios is very simple and says only: "enable sata raid" or "disable sata raid"

 

I didn't think it was possible to get RAID in the M570U - it only has a single hard drive compartment.

 

RAID is of dubious benefit. It sounds good on paper, but in practice it usually not so hot. As those above had said RAID 0 does not give a huge performance increase and does increase the chances for failure. RAID 1 gives the illusion of a good backup. In reality it is not as straightfoward as swapping drive in consumer grade RAID. It can take a little bit of voodoo to get up and running and it is possible to mess up the mirror in the process. Also, there are several instances where a backup that resides in the same computer is actually not a backup. Such as the system being fried by lightning, a fire, etc. RAID 1 should not be considered a good backup.

 

Requiring a bit of voodoo doesn't make it a less good backup. It's a good backup if it keeps your data, which it does. if you had to perform a secret ritual that could only be performed in a specific sacred grove, under a full moon and required the sacrifice of half a dozen squirrels to retrieve your backed up data, it'd *still* be an equally good backup, because it still holds your data after your other HD died.

Of course, it still resides in the same computer, which means it's not safe against everything that might happen. On the other hand, you're guaranteed that your backup is up to date, which is a lot harder to ensure with backups stored outside your computer.

So I'd say it is a good backup, but it's not perfect and if you need to store *really* important data, then use a combination of RAID 1 and frequent off-site backups.
But off-site backups alone isn't a good solution either, because you're pretty much guaranteed you won't have the up to date backup that RAID 1 gives you.

 

save the squirrels. And last time I checked....it was SEVEN hamsters....

 

Actually, that's not true at all. Even Windows can do a software RAID array, hardware support isn't strictly required. And no, it doesn't necessarily make things more efficiently stored. A larger array (singly formatted apparent drive/partition) will necessarily use LARGER block sizes to keep the file table, what you refer to as a database, a manageable size, or chew up lots of unnecessary space with a large file table and smaller clusters. Cluster size should primarily be chosen with respect to the size of files to be stored on the volume. If it's all just large media files, why mess with smaller clusters?

As for personal setups, I run a 4 drive RAID-5 software array for myself Not as safe as mirrored drives, if you do just a purely statistical analysis, but it's still better than just the drives alone.

 

If you mean i can have only one harddisk than your wrong. The M570U can have 2 harddisks intern.

 

Are you counting the modular bay hard drive? I haven't seen any retailers selling the Clevo M570U offering a RAID option.

 

He'd have to be. But then you'd be back to a software RAID setup. And I'm not sure how well Windows does software RAID on it's boot drive.

 

I saw xxodd did sell the M570U offering RAID0 or RAID1. But now they don't do it no more.