RAID 5 Data Corruption: Symptoms & Precautions

Since the discovery of RAID (Redundant array of independent disk) Data storage technique, user follows the trends of having mass storage capacity as well as ability to recover his/her data from any failure conditions. The most widely used and famous RAID Storage technique is RAID 5, require minimum of 3 disks and have some key features, such as:

• Fault Tolerance means increase data protection and integrity
• Increase storage capacity
• Faster performance

Many users believe that RAID drive has been made to not fault but in reality, it fails. In most of the cases RAID 5 array become failed or corrupted due to various unavoidable facts. For details, look around the topics mentioned below:

1. When one hard drive attached to RAID servers become failed, eventually the RAID arrays will start to run in degraded mode. After which, other disks in the array will have to suffer an equal stress which results in failure of second hard drive. So, consecutive failure in two drives attached to RAID arrays will leads to RAID 5 array failure.
2. RAID 5 controller failure
3. Any power surges, occurs with RAID 5 controller can malfunction RAID elements, RAID configuration or the hard drive itself.
4. Sometime, in an attempt to rebuild failed RAID arrays, you may enter wrong RAID parameters, which causes a sudden breakdown and complete system failure.
5. Logical corruption such as virus/malware attack, hard drive crash, human errors, RAID partition table corruption etc. Though, RAID Drives are made with fault tolerance which protects only physical failure but could fail in case of logical failure.

You should avoid doing any of the following activities to stay away from any data loss situations:

1. Stop using RAID drives in case of a single hard drive failure. Any remedial actions on such conditions will leads to damage on second hard drive and failed RAID arrays.
2. Don't try to remove or alter any hard drive attached to RAID arrays while system is performing any read/write operation.
3. Always remember or note down the various RAID parameters which greatly helps to successfully rebuild corrupted or failed RAID 5 arrays. The possible required RAID parameters could be :

• Disk Order
• Stripe Size
• RAID Header Size
• Parity Rotation
• Parity Delay

   4.  Do not operate any chkdsk or similar disk checking operation, as this command will run 

        in write mode and heavily responsible for overwriting the failed hard drive data.

   5.  If you've loose any important data from failed RAID arrays, it's advisable to wisely 

        choose any data recovery software.
 
P.S.: To recover data from failed RAID arrays using RAID recovery software, you are 

        also required to enter the correct RAID parameters which I have already described in #3. 

Other Useful Readings: 

http://en.wikipedia.org/wiki/RAID_5_write_hole

http://en.wikipedia.org/wiki/Data_corruption

OS X Mountain Lion set to roar. Coming this July 2012

Mountain Lion:Apple.com

The wait for Mountain Lion seems to be over as Apple Inc. has officially announced the new OS to be released in this July. The Apple Inc. made many mac owners curious in the beginning of the year 2012 by announcing the OS X M.L. to be released in summer time. Just wondering how many Mac users will go with the OS X update on their Macs. The numbers of users downloading Mountain Lion from the App store can be huge.

Have you noticed one thing that Apple is emphasising over. That's combining the features of its iPad, iPhone, iPod & bringing it to the Mac OS X. This is a smart marketing strategy by the Apple because its line of iPods, iPhones & iPad are already selling like hot cakes. And, the user also get a chance to enjoy their favourite application, features from these devices on Mac OS X.

So lets not wait and take a glimpse of what the Mountain Lion has to offer this July:

iCloud Integration:

As the concept of online storing & accessing data has become a fashion, M.L. brings the iCloud feature so that you can use the data & features of iPod, ipad & iphone all together on your Mac OS. You get access to your mailbox, phone-book contacts, doc files, notes etc. from iPad, iPhone, and iPod. And believe it and praise the synchronisation done by the iCloud, you make changes on the above features on Mac and it gets automatically updated on your other devices. Similarly, you change using any of the Apple device and get the update on Mac OS X.

To enjoy the service, just sign in once with the Apple ID & it sets up in your Apple OS & devices.

Reminders:
You will feel like having an extra brain to remember the important dates & work to accomplish. Add & manage several lists & keep updating them. With iCloud, the users are alerted for the reminders & deadlines as they approaches. The reminders are updated on Mac and other devices so you don't miss the bus.

Notes:
The purpose of notes is to write it down whatever comes in your mind so that at later point of time you don't' forget. But what makes this nots feature different from an ordinary note program is you can customize the notes beautifully with images, attachments etc. Can quickly share your note in your circle by an email/messages. Paste the urgent notes on your Mac OS desktop & with iCloud, a note either created or updated is shared on your iPhone, iPad, and iPod devices.

iMessages:
Here they come on Mac OS X making conversation more easy and interesting. With iMessages, Apple devices get synchronised that means if you say hello to your friend from Mac you can continue the further chat from an iPhone or iPod touch. Share your media easily with imessages.

Notification Center:
Every time there is something new a pops welcomes you. You receive notifications of mails, messages, apps, software update etc. Notifications don't stay for long on your desktop, they disappear quickly so you won't get interrupted.

Power Nap:
A Mac wakes up doing your job even when you send it to sleep. Mac doesn't stop updating your calendars, mails, contacts, notes, reminders even on sleep mode.

Dictation:
Convert your words into text by the use of in-built microphone.

Facebook:
We all love Facebook because it is the hottest thing on the web. Sharing & caring for your friends and circle is tips away as the new OS X is more FB friendly. Share images, links & add, read comments. Notifications let you update your status right from the notification centre.

Tweet with Mountain Lion:
To tweet simply sign once & share links, photos from safari browser, iphoto & Photobooth.

Beside all this there are some other exciting features to roll on:

AirPlay – Your Mac OS is conneced to the Apple TV.

Gatekeeper: The built-in application which guards the OS X from downloading malign apps & software.