Why RAID is not a good backup solution for private users
A sad but typical story about why one needs to use backups when dealing with computers
Last Night a friend of mine gave me his almost full 2 TB Western Digital Studio Edition that has a 2 drive RAID 0/1 built in. He told me that he used it with his mac and everything worked just fine. When he connected it to his PC and tried to move some data to the drive it stoped working, which is no surprise since the drive is formated as HSF+ in a RAID 0 configuration. Windows can not handle HFS and somehow managed to serverly damage the pratition table on the drive. After using all tools known to me such as TestDisk, Mac OS X disc utility and Ubuntus partition manager i gave it up as damaged beyond repair. The next step will be to use a data recovery tool to pull out the data, that is still intact on the drive, but all of these programs cost at least 100$. In addition we have to finde 2 Terabytes of free space to recover the data to which also will not come cheap.
Since he used the drive in a RAID 0 mode there was no backup anyway but the very same thing could have happened if it was set up as a RAID 1.
When putting together my home server setup I was considering using one of these RAID drives vs. two stand alone drives and I am glad I chose the two single drives.
Pro RAID
- the consumer versions like the western digital ones are really easy to set up
- good protection from hardware failure
- automatic data restoring
- only Raid 1 will give you some sort of backup
- RAID 0 gives you speed gains
- usually the read feature is a bit more costly than two stand alone drives
Contra RAID
- no protection from software errors
- if the RAID it self craps out on you there is very little chance on restoring things
- if you delete stuff it is gone on both RAID discs instantly
- if the partition is damaged both drives are affected
- the physical proximity of these raid drives makes it more likely to die together in case of power surge for example
- not very flexible – I can always grab one of my two storage drives and go to a friends house to get some data and when I get back home it just syncs to the other drive and everything is fine unless the unlikely case of both drives die at the same time
I do not recommend a single RAID 0,1 or 5 setup as a sufficient backup solution. Backup often, on different devices in different locations!!
Tags: Backup, Mac OS X, RAID, Western Digital