RAID is not the same thing as a backup. RAID gives redundancy and availability, but is not a backup. There is an old rule in backup called 3-2-1. Three different copies of your data, on two different media, with at least 1 copy *physically* existing somewhere else. RAID addresses none of these.
It comes down to some simple variables: - how much does your data matter - what is your budget - basic threat assessment (aka what could destroy your data) Having a second copy of your data on a USB drive is good, though you really want to automate the backup procedure. Only two copies though leaves you vulnerable, so you might think that adding a second drive into an array makes that a 3rd copy. Counter-intuitively this is not the case. You data can still be mangled by a single "thing" and so only "counts" as a single copy of your data. What RAID does is maintain uptime and access in the face of a drive failure. Two USB drives would technically be better than a single RAID 1, though you would still want automation and offsite. I have seen so many different storage technologies in the past 20 years, and the one thing that I take away from all of that is just how fragile they are. One advantage that we have today is that we can copy digital data easily and spread it around, reducing the risk of loss. It might seem like this is all a step backwards, but consider the analogue equivalent. Most of the pictures of my family in my lifetime were destroyed in a basement flood in the early 90s. It was not easy to copy pictures back then, certainly not as easily as the two clicks it takes today. Considering that we can now automate our backups so that we do not have to remember to take them, and can have those copies stored pretty much anywhere in the world that we want, we are definitely in a better position than we used to be. On Mon, Jun 2, 2014 at 12:08 AM, Joe S <joes...@shaw.ca> wrote: > Does not RAID with more than 1 drive give a backup? Why do I > need an additional hard drive to back up to? > > > On Sun, 01 Jun 2014 22:16:06 -0600 > Shawn Grover <sgro...@open2space.com> wrote: > > > I bow to the other info presented in this thread. But I can > > comment a little on the hardware. > > > > We picked up both a 2 bay and 4 bay QNAP box at work. Both > > have been running very reliably and are surprisingly quite. > > Both are loaded up with 4TB drives. The 2 bay unit is > > configured in Raid1, so it has a total of 4TB capacity (well, > > slightly less...). The 4 bay unit is configured with Raid10, > > giving us 8TB storage, with another 8TB of hot fail. The 2 > > unit device serves as an RSYNC target for the 4 unit device > > - purely a back up system. ( later picked up a cheaper more > > consumer brand 2 bay QNAP for home use and have enjoyed good > > success with it as well.) > > > > With this configuration we are reasonably sure we can recover > > data quickly should we ever loose a drive. This was NOT the > > case when the hardware RAID 5 controller on the storage server > > that pre-dated these boxes decided to crap out. Luckily I was > > able to get most of our data from the RAID 5 array before it > > went for good. > > > > The one thing I would do different with the current > > arrangement is to move the 2 unit backup NAS offsite. Now > > that it has been sync'd locally, doing RSYNCs over the > > Interwebs would be a minor inconvenience. We did some quick > > math about doing a remote backup of everything from scratch > > and arrived at somewhere between 2 to 4 weeks of solid data > > transfer, utilizing the available bandwidth we typically see. > > So I'd recommend a local RSYNC if possible, then move the > > backup device and then set up remote backups to minimize the > > data transfer hits for that initial backup. > > > > My thoughts. > > > > Shawn > > > > > > On 14-05-30 10:20 AM, Bogi wrote: > > > Hi Joe, > > > Having a single drive external, while better than nothing is > > > way not as good as having a 2 bay / drive raid 1 enclosure. > > > in terms of safety i am talking. A step up in terms of > > > safety would be a 4 drive raid 1 or 5 enclosure. A step up > > > in all these cases, is having the drives/enclosures as a NAS > > > device sitting in a different place (safer?) than the backed > > > up computers are, and connected with the network to them. > > > > > > Most 2-4 drive enclosures (that come with drives) state the > > > capacity as a raid 0, which can be tricky for the > > > uninitialized. A raid0 configuration will not increase > > > safety, in fact it will reduce it drastically, so when > > > looking at populated 2 - 4 drive units, as a rule of thumb, > > > half the capacity for 2 disk units (to get the capacity in > > > raid 1 terms). the 4 disk raids a bit more complicated. you > > > can treat them as 2 pairs, this halving the capacity, or as > > > a 4 disk raid 5, in which case you get 75% of the total disk > > > capacities. > > > > > > For direct connect enclosures, look for e-sata capability, > > > look for usb3 , specially if your backed up computer has > > > these ports, you can not go wrong with these features. > > > > > > For NAS devices, look for the once that have dual gigabit > > > Ethernet connectors, they usually perform better speed wise. > > > > > > If you are going to invest on a 2-4 or more drive external > > > nas unit, think about augmenting it with UPS (uninterrupted > > > power supply), for capacity, add up the power rating on the > > > NAS unit. If you want to skimp out on the UPS, just get a > > > surge protector, it's your data after all. > > > > > > Here are some pointers: > > > > > > Single drive, direct connection: > > > http://www.memoryexpress.com/Products/MX45802 > > > http://www.memoryexpress.com/Products/MX22324 > > > > > > Dual drive, direct connection: > > > http://www.memoryexpress.com/Products/MX40154 > > > http://www.memoryexpress.com/Products/MX43461 > > > > > > 4 drive, direct connection: > > > (do consider the noise of 4 drives spinning near your > > > desktop) > > > http://www.memoryexpress.com/Products/MX30898/Reviews and of > > > course the drobo: > > > http://www.memoryexpress.com/Products/MX42950 > > > > > > Single drive, NAS: > > > http://www.memoryexpress.com/Products/MX32282 > > > http://www.memoryexpress.com/Products/MX33812 > > > > > > Dual drive, NAS: > > > http://www.memoryexpress.com/Products/MX47066 > > > http://www.memoryexpress.com/Products/MX49052 > > > > > > 4 drive , NAS: > > > http://www.memoryexpress.com/Products/MX39139 > > > http://www.memoryexpress.com/Products/MX49654 > > > > > > And you still need to get your drives. > > > Generally look for NAS / Storage rated drives, Green rated > > > drives tend to perform poorly in raid environments. > > > Desktop / workstation rated drives will do fine, specially > > > under low/medium stress situations. > > > > > > > > > > > > > > > On May 29, 2014 Thursday 14:22:21 Joe S wrote: > > >> I was reading the reviews of external hard drives. I found a > > >> number had problems with reliability. I don't have > > >> experience with these, but need something for backing up my > > >> home computer. Are there any that can be recommended? I > > >> also thought of getting an enclosure and a regular drive in > > >> case I have to replace it in the future. Probably 1 TB or > > >> so. > > >> > > >> > > >> Thanks for suggestions > > >> > > >> _______________________________________________ > > >> clug-talk mailing list > > >> clug-talk@clug.ca > > >> http://clug.ca/mailman/listinfo/clug-talk_clug.ca > > >> Mailing List Guidelines (http://clug.ca/ml_guidelines.php) > > >> **Please remove these lines when replying > > > > > > _______________________________________________ > > > clug-talk mailing list > > > clug-talk@clug.ca > > > http://clug.ca/mailman/listinfo/clug-talk_clug.ca > > > Mailing List Guidelines (http://clug.ca/ml_guidelines.php) > > > **Please remove these lines when replying > > > > > > _______________________________________________ > > clug-talk mailing list > > clug-talk@clug.ca > > http://clug.ca/mailman/listinfo/clug-talk_clug.ca > > Mailing List Guidelines (http://clug.ca/ml_guidelines.php) > > **Please remove these lines when replying > > > _______________________________________________ > clug-talk mailing list > clug-talk@clug.ca > http://clug.ca/mailman/listinfo/clug-talk_clug.ca > Mailing List Guidelines (http://clug.ca/ml_guidelines.php) > **Please remove these lines when replying >
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