To RAID or not to RAID

Written by  on March 17, 2014 

 

The RAID Risk
RAID is not a true data backup system. RAID is a data security technology designed primarily to protect against physical hardware failure or loss of access to data due to hardware or electrical failure. Please see the table below which compares RAID to traditional data backup.

Data Risk Traditional
Backup		 RAID Cloud
Catastrophic Data Loss Okay FAIL Okay
Fire, Flood, Theft, Terrorism Okay FAIL Okay
Physical Disk Failure Okay Okay Okay
Denial of Service (DoS) attack
Bandwidth restrictions		 Okay Okay FAIL
Intentional malicious data corruption
due to virus or hacker attacks		 Okay FAIL FAIL
Non-Intentional data corruption
due to human error or system malfunction		 Okay FAIL FAIL

MrBackup guarantees at least eight (8) complete unique data sets. This means that if the data becomes corrupt due to software failure, user error, real-time data corruption or virus attack, MrBackup will still have several chronological complete unique data sets which may be recovered. This is the main difference between a true backup and a data security system such as RAID.

RAID technology is designed to provide data security through disk redundancy. As such RAID is aimed at protection against data loss and loss of access to data due to disk drive failure or power failure. The main problem with RAID systems is that undetected data corruption may lead to such damaged data being written to the actual RAID system. Due to the near-live mechanism used by RAID, it is possible to overwrite good data with bad data. The result is that in the event of undetected corrupt data being written to a RAID system, due to the RAID system, the result will be that such bad data will not be suitable to restore the original system. RAID is primarily aimed at maintaining live systems, it is not designed as a backup system. In the event of software failure, user error, real-time data corruption or virus attack, the damaged data will be written to the RAID disk and securely stored: keeping the useless data safe. A RAID system used as a main system disk is not intended as a replacement for backing up data. The solution is obviously to make and keep multiple backups of the same data.
From the Wikipedia: http://en.wikipedia.org/wiki/RAID

To RAID or Not to RAID? It is suggested that RAID and traditional data backups are not competing technologies, but supplement each other. Both RAID and traditional data backups form part of a data security strategy. Both are important, but not mutually exclusive. RAID is designed to provide maximum data security against physical failure and minimize system downtime. RAID in itself can however not restore data to a specific Point in Time. Traditional data backups could restore data to a required specific Point in Time. In the event of non-physical failure RAID offers no solution. With limited resources, RAID should take second place to traditional backups.

Category : backup • Data • RAID

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Comments

One Response

  1. MrBackup says:
    April 2, 2014 at 12:02

    This extract from TechCrunch illustrates a typical problem with RAID – it is a data security system, not a backup system!

    It was the guy handling the IT (and, yes, the same guy who I caught stealing from the company, and who did a slash-and-burn on some servers on his way out) who made the choice to rely on RAID as the only backup mechanism for the SQL server. He had set up automated backups for the HTTP server which contains the PHP code, but, inscrutibly, had no backup system in place for the SQL data. The ironic thing here is that one of his hobbies was telling everybody how smart he was.

    The full write up is on the TechCrunch site.