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chelseafan

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Thanks for all the replies, I think a raid server sounds good, does it back up instantly or do you still have to go through the laborious palava of backing up ? I presume with a raid server, if I save a file, it will also save the file to an alternate Hard drive as well. Could I run this from a laptop and are the HD's revoveable from the raid unit ?

Raid comes in various flavors, most popular being RAID1, RAID5, RAID10. There are others, but these are the ones that you see most often today. Most implementations are probably geared to businesses rather than personal computing, but, you certainly can implement it for personal use as long as your mother board has disk controllers that will support it. You do not have to have windows server as an OS or a NAS to implement, although RAID is probably most prevalent with either or those implementations. You can bring up raid under windows 7 or other OS's. Using the different types of raid usually implies some tradeoffs (space and potentially performance vs. availability for RAID1, and to a lesser degree for RAID 5 and 10).

 

RAID1 maintains data on one disk with a copy of the disk on some other disk. For the highest data integrity, during updates applications are usually held until the data is written to both disks. There are ways to mitigate this but those explanations don't belong here. Also there are different implementations of RAID1 which may or may not allow i/o to both the primary and the copy.

 

RAID5 and RAID10 are not 1 to 1 configurations, but rather you have multiple disks and you stripe the data across these disks (Stripe means that potentially a file is not written to one disk but is written across multiple disks, which in essence would speed up its access since all the disks me read simultaneously rather than a single disk read sequentially). RAID5 configuration can withstand the failure of a single disk because RAID5 maintains parity on all the data written. The parity may be written to an external parity disk or imbedded across the RAID array. But this allows the data, in the case of a single disk failure, to be rebuilt on the fly (i.e., as you are processing, with no interruption, downtime). Sometimes, the configuration might include and additional hot-backup disk which will be rebuilt automatically to replace the failing disk, therefore allowing you to replace (hotplug) the failing device without any disruption to service. You can see with the various "extra" disk type of implementations, where this becomes expensive and why it might be a business rather than personal configuration. Raid10 is an additional extension of RAID5 (with all the striping and etc. mentioned above) which will allow the configuration to potentially recover from 2 disk outages (if they hit in certain areas, i.e., it does not guarantee 100 percent recovery for 2 disk failures).

 

What I have quickly written here probably confuses you more than helps since RAID can be a pretty complicated subject. Go to Tomshardware.com, they usually have pretty good, extensive explanations of different HW configurations plus tips and aids for implementation. Wikipedia also has a good quick and dirty explanation without going overboard.

 

But think of raid much more of you have applications or business's that should never go down (like a bank or a forum (just a joke)). It can serve as a backup, but you still need a backup because if you ever corrupt data (ala a virus, or some kind of lack of integrity in processing) that corruption will be propogated across the RAID array (whichever one you choose). Backups, especially if you keep multiple versions can always give you the option of going back to the data before it was corrupted, RAID does not offer that.

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My friend is now hyping his NAS (Network-Attached Storage) system. It's his personal cloud server. Do some web searches to research it. Basically you buy your own server/storage device, attach it to your network and you're done. Well maybe you need to configure a bit. But for 100 or so bucks you can create your own cloud.

 

That's how I understand it.

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