Wednesday, 20 May 2015 00:00

On hard disk drives, RAID, backups, etc.

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Every computernik has at least once experienced a crash of hard disk drive containing valuable information.

b2ap3_thumbnail_iStock_000001576389XSmall.jpgThe first case of hard disk drive crash happened to me when my boss decided to play some games on a computer during defragmentation. Of course this computer contained thousands of important company files. It was long ago and computer had Windows 95, which crashed immediately after he started playing. Upon every reboot it displayed defragmentation window without any visible signs of progress. All information became mess, all documents – unreadable and those that I managed to open contained some unreadable stuff. Result-less efforts to recover information lasted two days and manual recovery of documents (typing from the printed documents) took much more time.

Another case happened to me again in the office. One of the computers caught ONE HALF virus. This virus has reformatted all data on hard disk drive into its own format. At that time it was quite difficult to find and download a decent anti-virus, but anyway I managed and launched the program to check for viruses. In the meanwhile my colleague was passing by and noticed that something awkward is going on with the computer and without thinking decided to unplug the computer from the mains. The result was predictable – messed up information. It was not as catastrophic as the first case because the latter taught me to backup important data which I did.

Third case happened to my personal computer – my expensive computer with 40 Gb Toshiba hard disk drive (that was a lot at that time) crashed just two days after the warranty expired... As it turned out it was an unlucky series and almost all drives of this series crashed. I managed to recover some small files but my grand music collection was irretrievably lost. The saddest was to lose the majority of 3D projects... At that time it was not possible to backup using floppies and recordable CDs were kind of expensive...

After that I have experienced many more crash cases but in the majority of cases I had backups, so it was easy though time consuming to recover necessary data. At the beginning the backup devices were CD-Rs and now its file server with large capacity RAID.

Latest case happened half a year back at work. Hard disk drive started ticking on one of the old computers. Again, thanks to backup we managed to recover all the documents except for documents created on the day of crash.

Until recently I was fortunate enough to avoid failures and crashes on servers... But inly until recently. No, it was not a big deal but it could have been – the party at fault was a very important server on which all financial documentation is being processed – if this server crashed, then all budget funded offices of our town would have been left without funds...

Last week I remotely logged into this server to adjust some settings and noticed a yellow triangle with exclamation mark in tray - Intel Matrix Storage Console required attention. After opening it I saw a S.M.A.R.T. event meaning that the number of read/write errors on one of the hard disk drives in the first array where the system is installed (second was designed for backups) exceeded the maximum permissible value. According to instruction a hard disk drive had to be replaced. Hard disk drives on that server were quite old. They were purchased in 2006 when I first joined the office and since then the server worked 24/7. Considering that there is no wander why it shows off.

According to instruction I had to pull out bad drive and replace it with a new one, but 120 Gb drives are no more available, so I purchased a set of identical Seagate Constellation server 500 Gb hard disk drives waited until evening, unmounted image from ill array, removed old drives, installed new ones, recreated RAID, created image – half an hour and it looks like new. It was even somewhat boring... Nobody even noticed the change except accountant who paid the bills... Even if something bad happened I could have easily recovered everything from backup and it would have taken me maximum a day to complete... So, the work of invisible front again was left invisible and the majority of users again think more and more that admins do nothing.
A lesson to newbie admins – backups, backups and again backups! If you have a possibility then its better not to save and upgrade RAID.

Last modified on Wednesday, 20 May 2015 15:31
Data Recovery Expert

Viktor S., Ph.D. (Electrical/Computer Engineering), was hired by DataRecoup, the international data recovery corporation, in 2012. Promoted to Engineering Senior Manager in 2010 and then to his current position, as C.I.O. of DataRecoup, in 2014. Responsible for the management of critical, high-priority RAID data recovery cases and the application of his expert, comprehensive knowledge in database data retrieval. He is also responsible for planning and implementing SEO/SEM and other internet-based marketing strategies. Currently, Viktor S., Ph.D., is focusing on the further development and expansion of DataRecoup’s major internet marketing campaign for their already successful proprietary software application “Data Recovery for Windows” (an application which he developed).

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