Is my RAID working?

[ray4389]

How can I check to see if my RAID is working?
I have 2x250gb running in RAID supposidily. They are both under my device manager, but I can only acess a single drive labeled C:\

Does that mean they are in RAID?

 

[tuskenraider]

Which RAID? If it's 0 you should see about 460-70GB total space available for drive C and you'll know your good. If it's 1, you should see about 230GB of space and you should have some kind of RAID utility included with the mobo driver disk to let you see both drives.

 

[kick]

Tusken makes a good point. With 2x250GB the available drive space seen by the OS can give an indicator as to whether the drives are members of an array. That said, it shouldn't be too hard to actually confirm. Most controllers offer a BIOS-like utility that's available during bootup and a software component that loads within the OS to monitor status of the array and other functionality, such as rebuilds, etc.

Arrays tend not to build themselves tho. Can you give a bit more info re: the controller involved here and how you set it up? Is this an add-on controller card or is it built into the motherboard?

 

[ray4389]

Which RAID? If it's 0 you should see about 460-70GB total space available for drive C and you'll know your good. If it's 1, you should see about 230GB of space and you should have some kind of RAID utility included with the mobo driver disk to let you see both drives.

I see like 230 so it must be RAID 1 and that would explain the performance. It writes faster (sata) and it reads much faster.

 

[ray4389]

Tusken makes a good point. With 2x250GB the available drive space seen by the OS can give an indicator as to whether the drives are members of an array. That said, it shouldn't be too hard to actually confirm. Most controllers offer a BIOS-like utility that's available during bootup and a software component that loads within the OS to monitor status of the array and other functionality, such as rebuilds, etc.

Arrays tend not to build themselves tho. Can you give a bit more info re: the controller involved here and how you set it up? Is this an add-on controller card or is it built into the motherboard?

All I did is put drivers on a floppy--hit f6 and that's all my mobo told me to do. I have no clue what's next? It's instructions ended there.

 

[valkon]

Right click on My Computer -> Manage
Select Disk Management. Do you see two drives?

 

[djnes]

I see like 230 so it must be RAID 1 and that would explain the performance. It writes faster (sata) and it reads much faster.

RAID1 doesn't offer any performance benefits. Hell, neither does RAID0 except in very unique situations.

 

[ray4389]

RAID1 doesn't offer any performance benefits. Hell, neither does RAID0 except in very unique situations.

RAID 1
Diagram of a RAID 1 setup.
Enlarge
Diagram of a RAID 1 setup.

A RAID 1 creates an exact copy (or mirror) of a set of data on two or more disks. This is useful when read performance is more important than data capacity. Such an array can only be as big as the smallest member disk. A classic RAID 1 mirrored pair contains two disks, which increases reliability exponentially over a single disk. Since each member contains a complete copy of the data, and can be addressed independently, ordinary wear-and-tear reliability is raised by the power of the number of self-contained copies. For example, consider a RAID 1 with two identical models of a disk drive with a weekly probability of failure of 1:500. Assuming defective drives are replaced weekly, the installation would carry a 1:250,000 probability of failure for a given week. That is, the likelihood that the RAID array is down due to mechanical failure during any given week is the product of the likelihoods of failure of both drives.

Additionally, since all the data exists in two or more copies, each with its own hardware, the read performance can go up roughly as a linear multiple of the number of copies. That is, a RAID 1 array of two drives can be reading in two different places at the same time, though not all implementations of RAID 1 do this[1]. To maximize performance benefits of RAID 1, independent disk controllers are recommended, one for each disk. Some refer to this practice as splitting or duplexing. When reading, both disks can be accessed independently and requested sectors can be split evenly between the disks. For the usual mirror of two discs this would double the transfer rate. The apparent access time of the array would be half that of a single non raid drive. Unlike RAID 0 this would be for all access patterns as all the data is present on all the disks. Read performance can be further improved by adding drives to the mirror. Three disks would give you three times the throughput and an apparent seek time of a third. The only limit is how many disks can be connected to the controller and its maximum transfer speed. Many older IDE RAID 1 cards read from one disk in the pair, so their read performance is that of a single disk. Some older RAID 1 implementations would also read both disks simultaneously and compare the data to catch errors. The error detection and correction on modern disks makes this less useful in environments requiring normal commercial availability. When writing, the array performs like a single disk as all mirrors must be written with the data. Note that these performance scenarios are in the best case with optimal access patterns.

RAID 1 has many administrative advantages. For instance, in some 365/24 environments, it is possible to "Split the Mirror": declare one disk as inactive, do a backup of that disk, and then "rebuild" the mirror. This requires that the application support recovery from the image of data on the disk at the point of the mirror split. This procedure is less critical in the presence of the "snapshot" feature of some filesystems, in which some space is reserved for changes, presenting a static point-in-time view of the filesystem. Alternatively, a set of disks can be kept in much the same way as traditional backup tapes are.

That said that read time is increased. Also where is this "manage" option in My Computer?
I see the C:\ drive and the I:\ drive that I accidently erased that is a USB one I have....

 

[tuskenraider]

RAID1 doesn't offer any performance benefits. Hell, neither does RAID0 except in very unique situations.

Apparantly you know more about my system and tested it when I wasn't home to make such rediculous statements. Leave the flamebait comments out of this thread and offer some help to the OP yeah?

To the OP, if you didn't actually create the RAID array, then I doubt it was just created for you. You should go into Disk Management like suggested and you might see another drive that was not initialized and formatted, which would be the reason you wouldn't see it in My Computer.

 

[MrMike]

That article says that read time is decreased, and that is correct.
It's write time that is increased with RAID1.

 

[ray4389]

Disk 0 is my C:/
Disk 1 is has no letter and says unallocated therefore not in RAID and not formatted?

 

[tuskenraider]

Correct. Right click and initilize the disk and format if you want two separate drives. If you want to actually set up RAID, you'll have to enable it in the BIOS and then create the array when the RAID BIOS pops up. You'll lose everything on both disks if you create create a RAID0 array at this point, though you might be able to keep your current active disk's data if you do a RAID1 mirror, but someone else will have to verify that, as it might just erase everthing on both drives as well. A reinstall doing RAID will require the correct drivers on a floppy to F6 during OS install.

 

[ray4389]

Ok it's formatted. Thanks for the help. SATA is really fast compared to IDE. I don't want RAID 0 anymore after reading how buggy it can be. RAID 1 will be an option for my server though when I decide to get more drives.

 

[djnes]

Leave the flamebait comments out of this thread and offer some help to the OP yeah?

Just because you take issue with something most other people already know, doesn't make it flamebait. You've had posts reported for flaming in several other threads, I hear...so don't lecture others on flamebait. Hypocritical, wouldn't you say? Just because you are close-minded, doesn't make others wrong...big difference.

I did offer help, and have in this OP's other threads, that have gone ignored. Several people are trying to reolve another issue of his, and all of our suggestions have gone ignored. Most people come here to learn more and have their questions answered...so when someone posts incorrect information, or something of the like, it's corrected. That's how it's always been on here, and that's how it still is.

 

[tuskenraider]

How can I check to see if my RAID is working?

This is the question and here is your answer:

RAID1 doesn't offer any performance benefits. Hell, neither does RAID0 except in very unique situations.

Sounds like a solution.

Just because you take issue with something most other people already know, doesn't make it flamebait.

What I know is that your blanket statement concerning RAID is wrong because it's been disproven by plenty of people, myself included, who actually test their own systems and have proven it wrong.

You've had posts reported for flaming in several other threads, I hear...so don't lecture others on flamebait. Hypocritical, wouldn't you say? Just because you are close-minded, doesn't make others wrong...big difference.

Yeah, I've gotten in a couple heated arguements here, so who doesn't once in awhile? I move on and only judge a person by their current disposition in the thread I'm partaking in. Maybe you should too. Good day.