Since I created a category for Synology NAS, I think I should have at least one blog reminding the correct usage of RAID.
Losing data stored on RAID 5 volume
Recently I read an article from a computer magazine regarding data loss on RAID device. The friend of the author was using RAID 5 as backup solution and finally experienced serious data lost due to some hardware issues.
“Oh, one more case today” I thought. In fact, there were already lots of similar complaint/screaming for help from many local web-based forum. “When will they learn about RAID and agree that RAID is not a backup solution at all?”
Once again, if you are new to your NAS, or recently got a 2 bays+ NAS for your home network, you may want to consider not wasting your storage and just say no to RAID.
My story of data lost on RAID 1 volume
I am running two 500GB Western Digital YS series in my DS207+ for over 1 years. Previously I setup as RAID 1 and thought my data will be kept safely because all data were duplicated to both hard drive. If you had read my older blog, you might remembered that my RAID 1 volume degraded periodically because there is a bug existed in WD YS series hard drive. And guess what, some of my video files were corrupted during volume repair process and cannot be recovered anymore.
That was my story of data lost related to RAID volume. I’m losing data even running RAID 1. ( I end up purchased another external USB hard disk and backup the NAS manually and periodically. I also setup openvpn to perform offsite backup for important data)
Fact of RAID
Fact 1: You still need to backup your data from RAID device to separate device in order to keep your data recoverable.
What RAID actually trying to accomplish is to increase data availability when hard drive crashed. However, it DO NOT backup your data, it just duplicating your data to different disk in order to minimize the amount of data lost if one or more hard drive failed within the RAID array. This is important only for business environment because this reduced the impact to daily business flow by reducing the amount of affected data. The less data being affected, the less influence to be made to the business. (Some business may losing customer if their data is offline during certain period!)
Fact 2: RAID is useful for environment where data accessibility and availability is important
For home usage, think about it, will you losing money if you can’t access your favoute MP3/movie files/photo album for couple hours? (unless you are running a home office..) No? then why running RAID if it does not protecting your data? Why losing certain amount of storage to setup a RAID volume if it is neither protecting your data nor increasing any productivity for normal home usage?
It is not the fault of RAID, it is the fault that most home user (like myself) were picking the wrong strategy to backup their data.
Anyway, there is nothing wrong if you setup RAID for your NAS for whatever usage, just remember to backup your NAS constantly 🙂