RAID 01
RAMWolff
Posts: 10,256
About ready to see if this is the solution I want.
Got my main drive backed up on a backup solution that's old, USB 2 sort of old but its' still humming away. This doohicky sort of external enclosure I got from NexStar has the instructions to flip the right switch down, this puts both drives in RAID 01. Hold the reset button with the drive running for like 10 seconds, release and then set up the one drive that now shows as available for mounting in the Computer Management area.
Got that done and now just making sure I have a few more things done and will start copying over the contents of the "G" drive to the new E backup setup.
The only issue I have is that I can't see the contents of the other drive. I got some tools sent my way to monitor but what if the first drive fails and I've only got the one drive, that's NOT mounted, left with all my backup's on it??
Any one using RAID 01 and if so can you please edjumacate me on this a bit??
Gracias!
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I don't view having hard drives in a RAID array as a means of making archival backups, but as a means to avoid down time from a catastrophic hard drive failure. By having a RAID 01 array, you're using a second drive to make a mirror backup of the primary drive in the RAID array. If the primary fails, the computer automatically starts using the secondary drive. You should get a system message of some sort that a drive in the RAID array failed signaling you to replace the failed drive. After the failed drive is replaced, the remaining working hard drive will be rebuilt to the replacement drive automatically.
You should not see nor can you access the non primary drives in a RAID array from the computer's operating system. You use the RAID utility software that comes with computer to monitor the health and view the disks configured into RAID arrays.
I tried it for a while mirroring the Computer's C: drive and also data drives, but since I installed a HP Data Vault to make daily backups via my network and disk image backups to external drives, I quit using RAID. I didn't like the idea I was tying up an extra drive and getting less life out of it. It would last longer if I used it as an external drive for off line disk image backups. I feel comfortable if I had a hard drive failure, I could take it off line and deal with it and use one of my other computers in the mean time.
Edit: Opps: My experience was with two mirrored drives in a RAID 1 disk array (not RAID 01) as clarified by DAZ_Jon.
Not sure if this is going to be a lot of help in you seeing the contents and health of your array, but in order for you to have a Raid 01 setup, you need a minimum of four drives (striped + mirrored). Two drives would be good for either Raid 0 or Raid 1. As for a backup solution, don't ever rely on Raid 0 as it isn't fault tolerant at all and increases your chance of total data loss versus backing up on a single drive. Raid arrays typically aren't used for a backup but for keeping fault tolerance and hardening systems actually in use. However, since you're already using the external drive for backup, if you can afford to have half your disk space available (so two 1TB drives will result in only 1TB of useable storage in a Raid 1 config) go nuts.
I'm guessing what you're talking about there is the ability to put it in a Raid 0 or Raid 1 configuration (I don't know of any desktop enclosures that have a raid controller capable of any more advanced raid levels). If that is the case, make sure it is in Raid 1 configuration as that will allow one drive to fail and the other to keep going without any data loss and for you to replace the drive and rebuild.
Anyway, if it is in a Raid configuration controlled by the enclosure, the fact that it is mounted means all drives in the configuration is mounted as far as the OS is concerned. So if a drive fails, the enclosure will automatically read from whatever disk it can for its data so all you really need to worry about is replacing the drive and running the process (if it isn't automatic) to repair the raid. Basically it gives you one disk level of redundancy so if a single drive fails, all your data is still accessible and read / writeable. Only if you don't replace the failed drive and repair the raid before the second disk potentially fails will your backup be hosed. This is all provided that it isn't some really poorly implemented bastardization of a raid setup.
Also, keep in mind, since it is most likely a separate backup that has the two disks in a raid configuration, you'll only actually need to pull data off if your main drive fails. So for total data loss, you're looking at your main drive, and both drives in your enclosure failing all relatively at the same time (or faster than you can get a replacement drive) in which case you would be one of the most unlucky people in the world or some sort of electrical surge / powerful magnet hit them all and wiped it out.
Hi and thanks for the helpful replies.
Sorry, yes, it is RAID 1. I didn't know there was a difference if I put the 0 in front of the 1 so I guess there is.
I don't like constantly backing up two drives, which has become my habit as my content, photoshop and ZBrush files have grown and I don't want to loose those files. After a while I would just forgo backing up the second drive altogether and that's just asking for trouble, similar to what happened to me earlier this year when my main BU drive from Seagate took a major dump and none of the content was salvageable (being a hairdresser and I'm well connected and a client of mine in the computer biz took it and had her guys, who do that sort of work for a living, couldn't save it and if they can't they said Seagate wouldn't be able to either) so that sent me a on a mad hunt for a better solution. IN the mean time Seagate sent me a replacement drive, that failed too. Then a third and that one died. I finally told them I'd had enough of these messed up external back up drives. SO I requested an internal Seagate Barracuda be sent out to me instead. I had a twin Seagate internal and was filling that up with backups and thought that there must be a way to mirror the drive I had. Sure enough there were quite a few EXTERNAL RAID enclosures on the market and since I've been using NexStar for a few years and have been very happy with their performance I got the set up I got.
So I don't care if I have a drive that's not being used, it is being used, it's being a mirror of my other drive and THAT'S very important to me. So not a waste as I'm seeing it.
SO then this RAID thing is something the system is aware of and from what you've told me, Lindsey, if one of the drives fails then the other is made visible and then when I get a replacement drive and stick it in the box the system will mirror what's on the other drive to that drive. Correct?
Thanks again, both of you! :-)
They are both being written and read from in that case (if it is doing it properly). The fact that it is two disks, or just one disk if one fails, is invisible to the OS in terms of how it reads and writes and is only exposed through either drivers to get its status or other software.
Best way to think of it as both disks are sharing the load and the encompassing entity (the Raid controller) is the go between between your OS and the drives. If one fails, then all the work goes to one disk with the controller still acting as the go between. When you replace it, it will bring the new guy up to speed and share the work load again.
Hmmmm, that seems confusing to me. I was told in RAID 1 that one drive is simply a mirror of the other drive I'm doing the backups on....
When a write happens, it happens at the same time on both drives. When data is read off the array, it pulls some from disk 1 and some from disk 2, combines it, and sends it over (over simplification, but thats the basic gist). All disks in the array are active, there is never a "passive" or inactive disk (if it was kept as a cold backup, there would be no guarantee that the disk was A) functional or B) free from bad sectors that have to be worked around or could compromise data integrity). In terms of how the data is on the disk, a mirror. In terms of how it is actually used and what happens in a fail over, both are actively doing things.
As far as actually in use, if a disk fails, you won't really notice it most likely and will get a warning either from software installed on your computer for the enclosure or a blinking light on it changing from green to red saying the disk is dead. It will keep going like nothing bad happened.
Hmmm, didn't come with any software. They did send me a free utility to monitor things but it's one of those weirdly shaped apps that was popular 10 years ago and I can't even pull it out larger to get all the smushed up info more readily viewable on it.
If you know of any utilities and other RAID softwares that are either free or low cost but high performance please post the links.
Thanks for the info on how this whole RAID thing actually works. Makes allot of sense to me now. No, really it does! :-)
There are lots of different versions of RAID (even two meaning to what RAID means!).
In essence, as has been mentioned, RAID is there to make simpler, better, faster or more resilient for you. Not all forms of RAID will achieve all of those!
I could rattle on all day and just make it worse, so go have a look at this - with pictures!
First it depends on weather you are using a hardware or software RAID 1 solution. I personally hate hardware raid solutions as far more often the raid card fails than any disks which renders the disks useless until you find a card from the same manufacturer, same model.
I use software RAID on all my my machines where needed. It basically halves the speed of the disk but make it much more crash resistant.
Thanks Simon. Bookmarked.
Totte, can you please post a fav link to software you like? Thanks!
I use Mac OS X where it's built in ;-)
I use Mac OS X where it's built in ;-)
Ah, well there's that! lmao
Ok let's make it simple. When using RAID 1 with an external enclosure, the RAID 1 function should be handled by the hardware (partially in fact but it doesn't really matter in your case). If setup correctly, your two drives are written at the same time, and you only see one "Disk" in Windows provided that at least one HDD is working so you don't have to bother about anything as everything is transparent to the user.
Your manufacturer may have tools to monitor your RAID System. It is always so, as the monitoring software has to react to specific hardware. There is no universal tool for that
I recommend to test a bit your setup
- Copy a few files on the Raid Array. I don't know if yours support hot plug too so let's make it safely :
- Shut down your computer. Then take one of the disk out. Startup your computer then check if you get an alarm somewhere and if your RAID Array is visible and has all the files.
- If everything is ok, shutdown again, then take out the current disk, and put back the one you took out earlier. Startup your computer then do the same checks as before
If you have the same content in the second disk then everything is fine and your system works properly
Last check that you could do if you want : copy some additional files on the Raid Array, then shutdown your computer and put back your 2nd HDD. Startup your computer.
If you have a digital display or a monitoring tool that can tell you the Enclosure's activity it should say that it is resynchronizing the two drives from the one that has additionnal files to the other and you should see them in the RAID Array. If it synchronize the other way then that is a point you should check with your manufacturer (it may always synch 1->2 instead of writing a timestamp to know which one to synchronize).
Hmmm, just found this one...
http://snapraid.sourceforge.net/compare.html
Thanks for the advice Takeo! :-)
I have a non-RAID mirrored backup drive of the data drives in my computers. I'm using Second Copy for backing up to the 2nd drive, it can be set to watch folders so new or changed files immediately are backed up automatically.
Thanks for the tip Taozen. I can't seem to access their web site! :-(
I was able to get it via Download.com
http://download.cnet.com/Second-Copy/3000-2242_4-10006600.html
But it worries me that if i love this and they are not running their web site correctly and my 30 days run out I'll be screwed.
Does this do real backups or does it save the files in some cryptic format??
Here's another package you may want to look at - SyncBack; it 'just' copies files to your backup device, so they are in standard, easily viewable format. I've been running the SE version for more than a year now, and am quite happy with it. The copies are 'smart' - only changed files (size or time stamp) copy and you have the option of keeping file no longer present on the source side (a backup) or cleaning them out (mirroring the source side).
I've been using it for 15 years now and never had problems with their website or anything, so it must have been a temporary glitch. Their support it great too.
http://www.secondcopy.com/
By default it will simply make a plain copy of the selected files and folders on the 2nd drive. There are lots of different options and settings so you can get it almost any way you want. Also backs up to FPT sites.