raid 1 | DataRecoveryUnion.com

I am puchacing a new computer that is configured for raid 0. I would like to reconfigure it for raid 1. I prefer to reinstall win 7 to get rid of the junk new machines are shipped with so OS reinstallation is not a problem. Will I need new drivers or hardware (it is a Dell XPS system).

Change From RAID 0 to RAID 1

It should be fine. Just download all necessary drivers from dell. You may want to create media disks before doing this so that you can restore to factory settings if need be.you need not new hard drives, as we know the raid 0 is congifure with two hard drive, and raid 1 also need 2 hard drives, you just recongigure the raid array, and reinstall the windwos 7, that’s OK, you’d better do a fresh format before reconfigure.

Hard Disk Repair

RAID 1 Disadvantages

DATARECOVERYUNION.COM12 years ago4 years ago08 mins

I am in the process of building a new PC and since my data is important. I am considering using RAID. I currently have an external HD which is being backed up using Norton Ghost, but I would feel much more comfortable with real-time protection I’ve read that with on-board RAID controllers, the performance hit for RAID 5 is enormous, so I’m leaning towards RAID 1. I will be using WD 750 Gb Black hard discs on a GIGABYTE GA-P55A-UD4P motherboard using Windows 7. Is the only disadvantage to RAID 1, the ‘loss’ of a hard disc and a slightly more complicated O/S install with the advantages of data protection and a potentially slightly better read performance?

The big advantage or RAID1 is “instant recovery” from HDD failure. That is, if a member of the array fails, the RAID system immediately should detect that situation and convert the operation to using only the remaining good drive so that you can keep on functioning normally right away. It should also immediately send out a warning message so that you know of the problem and can plan its repair as soon as possible. The “downside” of this is that it can work so smoothly that the warning message goes un-noticed or is ignored by untrained users and the tech guys are unaware a problem needs attention. That’s probably not your situation.

The RAID1 systems I have used have very good tools for fixing a drive failure. Basically they will pinpoint exactly which drive is faulty so you can replace it. Then they will allow you to control re-establishing the array by copying everything from the good drive to the replacement unit. There is no need to re-install an OS or restore data from a backup dataset. They even can do this while the system is in use, although my preference would be to do the re-establishment as a separate operation on a system that is NOT being used for anything at the time.

My wife runs a retail store with a POS software package on a dedicated computer. The data files for that operation are kept in one subdirectory and amount to about 60 to 70 MB of data that are updated with every sale. The files are generally in ASCII character strings with some numerical data, so they compress well to .zip files. I set up the machine with a pair of drives in RAID1 as the only drive system. I installed WnZip Pro and set up a scheduled task that runs every day at 10 minutes before midnight (store is closed). It zips all the files in the specific subdirectory into a daily .zip file named with a date string and puts them in a designated subdirectory. This guards against data file corruption by providing end-of-day archived versions. Once a month (probably should be more often) I simply copy the end-of-month .zip file to a USB drive and take it home where I put it on my home computer – thus an off-site backup monthly. Then I delete all the daily .zips at the store, except for that month-end one. (So the store computer has on its RAID1 array an end-of-month .zip file (for every month since its start), each containing a snapshot of all the data that changes over time.) Small important step: the POS computer normally runs 24/7, so when I do the monthly .zip file copy I also reboot the machine and watch the POST messages to be sure there are no errors in the RAID system that I have not heard about.

We had a failure, but not of a hard drive. The mobo failed and had to be replaced. That can be a big problem with any RAID array based on mobo built-in “controllers” because there is no real universal RAID standard. That means often a RAID array written in one system cannot be read by another. In choosing the original mobo (by Abit) I deliberately chose one that had an nVidia chipset because their website claimed that they guarantee that ALL of their mobo chipset RAID systems use the same RAID algorithms and would continue to do so, so that any yet-to-come nVidia chipset could handle any older RAID disks made with their chips. When the mobo failed I selected a Gigabyte replacement mobo with a similar (but not identical) nVidia mobo chipset. Swapped everything, plugged it all together, and booted expecting maybe I’d have to do a Repair Install at least. It just booted and ran perfectly first time – no trouble at all! WOOHOO! I never had to reconfigure or re-install anything, other than updating the mobo device drivers from the Gigabyte CD.

So if you plan for possible changes to the RAID controller system as well as for changes to a hard drive that fails, a RAID1 system can give you some data security and continued operation through disk failure. You just have to recognize the need for real data backups and do them (AND VERIFY, as you say), probably more often than I do it.

Hard Disk Repair

To RAID-0 or Not To RAID-0

DATARECOVERYUNION.COM12 years ago4 years ago03 mins

I was thinking about going down the RAID road with my rig and was wondering what people think is best RAID-0 or RAID 0+1(This is what i was thinking) or is there a better option advice would be well recived befor i go spend £150 on 3 more new drives to make the 4 needed for 0+1 and could you tell me how RAID 0+1 and RAID 1+0/10 differ please.

As was said up, it’s necessary to know the application before accurate advice can be given. RAID 0 will benefit you in database access, huge spreadsheets, video editing, CAD rendering and a few other specialized apps. For everybody else, all its going to do for you is getting you bragging rights for good benchmark scores.

If you need data redundancy, and in reality who doesn’t, RAID 1 is a viable solution. For most data control situations an NAS presents a very convenient alternative and it easily performs the same job for multiple boxes. All data can be kept on the NAS with images of a standard “programs drive” as well as individual boot drives for each machine on the network, making cold metal restores a cinch. Many proprietary RAID formats will even allow ya to do rebuilds and expansions on the fly via “Hot Swap”. It’s also rather “portable” and the joke in my SOHO is that in case of fire, I can grab the NAS handle and run …. and after the data is safe come back in for the any employees, wife, kids, etc.

If your concern is only “one box”, RAID 1 provides data redundancy…..but so do other alternatives …. i.e. tape / optical, cloud backups …… RAID 0 , again unless you have specialized applications, will serve no observable benefit other than nice benchmark scores.

Hard Disk Repair

How to sepup a RAID 0/1 Array with WD SATA RAID Controller?

DATARECOVERYUNION.COM14 years ago4 years ago07 mins

Steps to setup A RAID 0 and RAID 1 Array with WD SATA RAID Controller & Two SATA Hard Drives

1. Steps to create a RAID 0 Array:

With the computer powered off, follow the instructions for installing the RAID controller correctly and connect both Serial ATA hard drives to the controller.
Boot your computer with the controller and drives already installed.
Watch your boot screens for a prompt that will ask you to press the Control and F keys at the same time to enter the Fastbuild utility and press those keys to enter.
Press the 1 key to enter Auto Setup.
Verify that the top of the screen says Optimize Array for: Performance.
If the top of the screen says Security instead of performance, highlight the word Security and press the right arrow button to change the word to Performance.
You should see that two hard drives are being used in the array and you will also see the total size of the array in MB.
Press the Control and Y keys at the same time to save the array configuration.
Press the Y key to create and quick initialize the array.
You will be warned that all data on the drives will be erased, press the Y key to proceed.
The array is now created, press any key to reboot.

Note: A RAID 0 array is not fault tolerant. It is recommended that you backup any important data that you decide to store on the array.

2. Steps to create a RAID 1 Array:

With the computer powered off, follow the instructions for installing the RAID controller correctly and connect both Serial ATA hard drives to the controller.
Boot your computer with the controller and drives already installed.
Watch your boot screens for a prompt that will ask you to press the Control and F keys at the same time to enter the Fastbuild utility and press those keys to enter.
Press the 1 key to enter Auto Setup.
Verify that the top of the screen says Optimize Array for: Security.
If the top of the screen says Performance instead of Security, highlight the word Performance and press the right arrow button to change the word to Security.
Press the Control and Y keys at the same time to save the array configuration.
Press the Y key to create and quick initialize the array.
You will be warned that all data on the drives will be erased, press the Y key to proceed.
The array is now created, press any key to reboot.

Note: A RAID 1 array is designed for fault tolerance. You will not notice any performance increase in your computer after creating a RAID 1 array. A RAID 1 array uses the second hard drive to copy the data of the first drive. Should one of the hard drives fail, you will still be able to boot your computer using the second hard drive.

Important: After creating a RAID 1 array, the total capacity of both hard drives will not appear as usable space in Windows. Because the second hard drive is being used to store the exact same data of the first drive, the usable capacity in Windows will be the capacity of only the first hard drive.

* To use the array for extra data storage only:

Install the latest service pack for your operating system to enable large drive support and use Disk Management to partition and format the array.

* To use the array as your bootable system drive:

Set your BIOS to boot to CD first and boot from your Windows 2000/XP CD to load your operating system onto the array.
Windows will treat the array as one large drive and will install on the array just as it would on a single drive.
When you are prompted by Windows setup to press the F6 key to install SCSI or RAID drivers, you will need to press F6 and insert the driver disk that came with your RAID controller.
Once the drivers for the controller are installed you will be able to finish the installation of Windows 2000/XP onto the array. After the installation of Windows, please install the latest service pack for Windows to enable large drive support and avoid data corruption.

Note: Your system BIOS may require you to change the order of your boot sequence before you can boot your computer from a controller. For more information about adjusting options in your system BIOS, please contact the manufacturer of your computer or motherboard.

Hard Disk Repair

Which RAID Mode Should You Choose?

DATARECOVERYUNION.COM15 years ago4 years ago03 mins

1. Speed (RAID 0)

Set in high-performance mode (also called striped mode or RAID 0) the storage system gives you the power you need when you’re:

Designing huge graphics and need a lightning-fast Photoshop scratch space.
Recording large DV files while maintaining clean audio performance.
Editing DV or HD video and want a smooth work flow with no dropped frames.
Rendering complex 3D objects or special effects.
Performing disk-intensive database operations.
Driven to be the first geek on your block with a computer so fast it blows your
socks off.

Why is RAID 0 so fast? It’s a bit complicated, but suffice it to say that two or more heads, or in this case, drives, are better than one. Picture multiple hoses filling a bucket at the same time or several men bailing a boat and you can understand why two drives striped are

faster

than one. Data is saved (striped) across both drives and accessed in parallel by all the drives so you get

higher data transfer rates

on large data accesses and

higher input/output rates

on small data accesses.

2. Data protection (RAID 1)

Set the system to data protection mode (also known as mirrored mode or RAID 1) and the capacity is divided in half. Half of the capacity is used to store your data and half is used for a duplicate copy.

Why do I want that kind of redundancy? It’s your data, your family pictures, your movie of baby’s first steps, your first novel. Is it important? You decide. If it is, then RAID mirroring is for you.

3. Data protection and speed (RAID 5)

In systems with three or more drives. we recommend that you set the system to RAID 5. This gives you the best of both worlds: fast performance by striping data across all drives; data protection by dedicating a quarter of each drive to fault tolerance leaving three quarters of the system capacity available for data storage.

Data Recovery

RAID Data Recovery Is Possible!

DATARECOVERYUNION.COM16 years ago4 years ago14 mins

What if your hard drive decides to enter the Elysian Fields in this very moment? Sure, you could simply get a new hard drive to substitute for the defective one with a quick run to your favorite hardware store. And with last night’s backup you might even reconstruct your installation quickly. But what if you don’t have a backup? The truth to be more like this: many users don’t even have a backup, or it simply is too old and thus useless for recovering any useful files at all. In case of real hard drive damage, only a professional data recovery specialist can help you – say bye-bye to your vacation savings!

Hard drive failure is especially disastrous for smaller companies working with a single server and a single disk, if they do not have a complete and working data backup at hand. The whole situation is even more complicated if the broken hard drive is a member of a RAID array. Neither hard drive failure in RAID 1 nor RAID 5 will result in data loss, since this scenario has been taken care of by the choice of these RAID levels in advance. But the risk of human error increases: self-made data loss occurs if you accidentally substitute the wrong drive in a degraded RAID 5 array (one with a failed hard drive).

But not all hard drives that show failure symptoms are defective. Sometimes, so called “soft errors” can be fixed using data recovery software. But even in this case, you should weigh the risks to see if it makes sense to take care of the problem yourself or get help from professionals. You might not be able to detect a controller failure right away, for example; usually, users assume a problem with the hard drive. Here is our rule of thumb: if you hear clacking sounds in the potentially defective hard drive, or if the computer’s S.M.A.R.T. function indicates an error during the boot process, something is wrong for sure.

What can you do once you know that an important hard drive is definitely broken? Or what happens if you pulled the wrong drive out of the slot while you were desperately trying to save your data? First of all: don’t panic! You need to act systematically and thoughtfully to be successful, as well as to ensure that you spend as little as possible on recovery – costs can hits four digits easily.

Data Recovery

Raid 1 Data Recovery

DATARECOVERYUNION.COM16 years ago12 years ago013 mins

1. Raid 1 Data Recovery FAQ

Q: What is the definition of a “RAID 1” volume?
A: “RAID 1” refers to a “Redundant Array of Inexpensive (or Independent) Disks” that have been established in a Level 1, or mirrored, drive set. A RAID 1 volume is a set of disk drives that are configured for data to be written to 2 volumes simultaneously. This configuration provides complete data redundancy in the event of a drive failure.

Q: What is meant by the term “mirroring”?
A: Within a mirroring (RAID 1) volume, the exact same information that is written to one disk is also written to a second disk, creating a “mirror image”, or clone, of the orginal hard drive.

Q: What number of drives are needed for a RAID 1 volume?
A: A minimum of at least two (2) hard drives are required to create and maintain a RAID 1 volume. Unlike some other RAID configurations, RAID 1 volumes require an even number of drives to be used.

Q: What are the differences between “hardware” and “software” RAID 1 configurations?
A: With a software-based RAID 1 volume, the hard disk drives use a standard drive contoller and a software utility provides the management of the drives in the volume. A RAID 1 volume that relies on hardware for management will have a physical controller (either as an expansion card or as a part of the motherboard) that provides for the mirroring of data across the hard drives in the volume.

Q: What are the positive reasons for configuring drives as a RAID 1?
A: A RAID 1 (mirroring) set will provide redundancy, or protection against one of the drives failing during use. With a RAID 1 disk volume, information is written to the first drive and then to a second (or “mirror”) drive at the same time. If one of the hard drives in the mirror volume fails, the remaining hard drive can be placed in service as a single drive with no loss of information. Similar to a RAID 0 (striped) volume, RAID 1 volumes require a minimum of two (2) drives.

Q: What are the arguments against RAID 1 configurations?
A: RAID 1 (mirroring) results in loss of half of the physical storage capacity of the drives comprising the volume. For example, if two (2) 500GB hard drives are configured as a RAID 1 volume, only 500GB is available for data storage. Using the same drives in a RAID 0 (striped) configuration, total data storage would equal 1000GB (or approximately 1 terabyte). Also, if damaged or corrupted data is written to one drive, it is also written to the second drive. Many people mistakenly assume that they are totally protected against data loss with a RAID 1 volume, but nothing could be further from the truth. A RAID 1 volume provides a measure of protection against data loss, but it does not eliminate the need for regular backup of critical data.

Q: Can RAID 1 be combined with another type of RAID, such as RAID 0?
A: The combination of a mirrored configuration with striping added is referred to as RAID 1+0 (also called RAID 10). In this scenario, the configuration will provide mirroring (RAID 1) across two (2) or more drives and will “stripe” the data in real-time to a second mirrored drive set. This unique combination will provide data redundancy and some speed advantages, but it does so at the expense of usable storage space. A volume established as a RAID 1+0 volume provides a little more data protection than a RAID 0+1, and will need four (4) hard drives at a minimum to be configured.

Q: Can data be recovered from a re-formatted RAID 1 volume?
A: Many times information is still recoverable, depending on how the drives were re-formatted. A high-level re-format (using Windows, for example), will create what will appear to be a new “clean” volume – but the original data will still be on the disk in the “free and available” space. A low-level format routine (as performed using the controller software) will overwrite every sector, and in the process destroys the original data.

Q: Could data recovery software utilities be used to recover my RAID 1?
A: Perhaps, but it wouldn’t be the safest approach. Most data recovery software will require the read / write heads to constantly travel over areas of the original disk that, if there is any physical damage, could render the surfaces useless and beyond recovery. The safest method of recovering data from a failed or corrupted RAID 1 volume (or with any storage device) is to create a block-level copy of every sector on each hard drive. The copied image is then used to reconstruct the original volume and rescue the required files and directories. This approach, while more time consuming, maintains and preserves the physical integrity of the drive media and limits the number of times that the original drive needs to be accessed.

Q: With RAID 1, if both mirrored drives fail, can data still be recovered?
A: In many situations, data will be recoverable. The quality and integrity of the data recovered will depend on the extent of the damage incurred to each failed storage device. If the mirrored volume was operating properly up to the point of failure, then there should be identical copies of the data on at least two (2) drives which will provide 2 chances to recover the same data.

2. How Raid 1 Data Recovery?

RAID 1 creates an exact copy (or mirror) of a set of data on two or more disks. This is useful when write performance is more important than minimizing the storage capacity used for redundancy. This is thought to be a foolproof method of data protection, but we commonly receive RAID 1 arrays that have failed due to:

corrupted mirrors

bad data from one drive moves to the other drive

mirror breaks, and does not allow system to boot

improper rebuild

The array can only be as big as the smallest member disk, however. A classic RAID 1 mirrored pair contains two disks, which increases reliability by a factor of two over a single disk, but it is possible to have many more than two copies. Since each member can be addressed independently if the other fails, reliability is a linear multiple of the number of members. To truly get the full redundancy 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. Like RAID 0 the average seek time is reduced by half when randomly reading but because each disk has the exact same data the requested sectors can always be split evenly between the disks and the seek time remains low. The transfer rate would also be doubled. For three disks the seek time would be a third and the transfer rate would be tripled. 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.

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.

Data Storage

RAID Array & Server Glossary of Computer Terms (Letter R)

DATARECOVERYUNION.COM16 years ago7 years ago06 mins

RAID
Redundant Array of Independent Disks, a collection of two or more disks working together in an array. Mylex RAID controllers implement this technology to connect up to 15 SCSI devices per channel. The different forms of RAID implementation are known as “RAID levels.” See also Berkeley RAID Levels, Disk Array, and RAID Levels.

The system manager or integrator selects the appropriate RAID level for a system. This decision will be based on which of the following are to be emphasized:

Disk Capacity

Data Availability (redundancy or fault tolerance)

Disk Performance

RAID Adapters
See RAID Controller

RAID Advisory Board (RAB)
An association of companies whose primary intention is to standardize RAID storage systems. Mylex is a member of RAB.

RAID Controller
Low cost RAID controllers that use SCSI channels on the motherboard.

RAID Levels
Mylex disk array controllers support four RAID Advisory Board approved (RAID 0, RAID 1, RAID 3, and RAID 5), two special (RAID 0+1, and JBOD), and three spanned (RAID 10, 30, and 50) RAID levels. All DAC960, AcceleRAID, and eXtremeRAID series controllers support these RAID levels. See also Berkeley RAID Levels.

– Level 0:
Provides block “striping” across multiple drives, yielding higher performance than is possible with individual drives. This level does not provide any redundancy.

– Level 1:
Drives are paired and mirrored. All data is 100 percent duplicated on a drive of equivalent size.

– Level 3:
Data is “striped” across several physical drives. Maintains parity information, which can be used for data recovery.

– Level 5:
Data is “striped” across several physical drives. For data redundancy, drives are encoded with rotated XOR redundancy.

– Level 0+1:
Combines RAID 0 striping and RAID 1 mirroring. This level provides redundancy through mirroring.

– JBOD:
Sometimes referred to as “Just a Bunch of Drives.” Each drive is operated independently like a normal disk controller, or drives may be spanned and seen as a single drive. This level does not provide data redundancy.

– Level 10:
Combines RAID 0 striping and RAID 1 mirroring spanned across multiple drive groups (super drive group). This level provides redundancy through mirroring and better performance than Level 1 alone.

– Level 30:
Data is “striped” across multiple drive groups (super drive group). Maintains parity information, which can be used for data recovery.

– Level 50:
Data is “striped” across multiple drive groups (super drive group). For data redundancy, drives are encoded with rotated XOR redundancy.

Note: The host operating system drivers and software utilities remain unchanged regardless of the level of RAID installed. The controller makes the physical configuration and RAID level implementation.

RAID Migration
A feature in RAID subsystems that allows for changing a RAID level to another level without powering down the system.

Read-Ahead Cache
A caching strategy whereby the computer anticipates data and holds it in cache until requested.

Recovery
The process of reconstructing data from a failed disk using data from other drives.

Redundancy
The inclusion of extra components of a given type in a system (beyond those the system requires to carry out its functions).

Rotated XOR Redundancy
XOR refers to the Boolean “Exclusive-OR” operator. Also known as Parity, a method of providing complete data redundancy while requiring only a fraction of the storage capacity of mirroring. In a system configured under RAID 3 or RAID 5 (which require at least three SCSI drives), all data and parity blocks are divided amongst the drives in such a way that if any single drive is removed (or fails), the data on it can be reconstructed using the data on the remaining drives. In any RAID 3 or RAID 5 array, the capacity allocated to redundancy is the equivalent of one drive.