Posts tagged with "server"

RAID 5 Data Recovery

lenovo raid serverI have a lenovo ix4-300d with 4 bays, each with a 2TB HDD in a RAID5. This evening it reported a data storage fault and auto-recovery email. Then a data protection reconstruction completed but with some potential data loss. When accessing the share it appeared as though half of the data that was present was missing from the share. I checked the interface and it showed an error with bay 1 that had a recoverable error. However, following a data integrity check and reboot the device came back online with only 1 drive showing data and prompting an overwrite of drive 3 which i didn't activate. I replaced the drive in bay 1 with a new 2TB HDD and rebooted to try and rebuild, suspecting it was drive 1 that had finally broken, again, prompted to overwrite but this time on drive 1 (the new replacement disk) i couldn't get the lenovo to overwrite the new disk 1, and was stuck in this state. Had to cold power down the box and replaced the original disk 1 back in the device. When the box was online, no shares were present at all, and the device was prompting an overwrite of the drive in bay 3 which i've ignored.

The automated errors sent on email state: "Storage failed and some data loss may have occurred. Multiple drives may have either failed or been removed from your storage system." At this point, decided to contact Data Clinic ( I'm happy to send the entire unit up to you and have a screen shot from this very morning with the size (2.32TB) and number of files (138,163) that should be across the 4 bays in the RAID5. Would appreciate an initial email on Monday rather than call back to advise of likely costs of review and data retrieval. Happy to send 2x 5TB external HDDs with the lenovo for backups.

We have an old windows 2003 server that we inherited from a merger and need to keep running for a legacy database. The server now won't boot. We suspect it to be a hardware fault but not entirely sure what at this stage. The RAID disks seem to be ok and the data intact as we can access it when we use a caddy attached to another computer. We cant get it to boot in another computer though and it just wants to run a windows repair and we don't have the administrator password. We basically need to get this disk booting into Windows again so that we can access the database. Again, this is another job for the RAID recovery experts at Data Clinic.

Windows 2003 server fault

Fault Finding on Dell Servers

Lets say your server falls over - what are you going to do?
Dell logoThe first thing most of us would do would be to perform what's known as a 'power cycle'. This is a technical term for 'switch it off and switch it back on again'. So the next time you do this, simply tell people that you power cycled the device and everything worked again and they'll look at you all impressed while they wonder what 'power cycling' actually is.

Although many of us do it, power cycling can be very detrimental in certain circumstances.  Its not a problem if we do it to our mobile phones if they crash for some reason, but a rule of thumb is the larger the system and the amount of data, the more risky it is the power cycle. This is especially true on Dell servers - and in particular Dell RAID servers.

Why Power Cycling is Bad on Dell Servers

Any device that processes a lot of data, whether it be a server, RAID, external hard drive, is going to encounter problems if it is power cycled. This is because storage devices and particularly Dell systems write data to their storage disks almost continuously, and one of the operations best avoided with any Dell system is to perform a power cycle when data is being written to the hard drives.

It's impossible to tell when data is being written the the disks on Dell systems, but if the write operating is interrupted it can easily lead to data corruption which is obviously very damaging.

How Does The Data Corrupt?

According to Dell experts Data Clinic, data corruption occurs because not all data that is scheduled to be written to the disks is actually written. They have documented the failure process on Dell servers (in this case the Dell MD1000) on their page at The process works as follows

  • Data to be written to disk is transferred into the server's memory cache
  • A write operation that transfers the data from the cache and writes it to the disks in actioned
  • A power cycle interrupts this process before it is completed and the operation is not completed correctly. This corrupts the data.

What To Do?

If you run Dell servers and encounter problems like this I strongly advocate that you don't try and sort the problem yourself: data corruption is a very tricky issue and more often than not you'll end up making the situation worse. Instead call in a data recovery company like Data Clinic who will be able to help you. Other data recovery service providers can be found at and

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