RAID or duplicate copy?

[papaschtroumpf]

I think this belongs in the HW forum...

 

Among other things my Mandriva machine is being used as a UPnP media server (running TwonkyMedia server with D-Link DSM-520 client). This means that I have a rather large collection of music (almost 30Gig) and a fast growing collection of movies (still in the process of ripping all my DVDs to DivX).

Given how painfully slow it is to rip everything, I would hate to do it again in case of harddrive failure.

There is too much to do backup on DVDs, so I could use a 2nd harddrive to make a 1:1 copy of my media directory, or I could use RAID to get redundancy.

 

how easy is RAID to setup? what are the pitfalls? can you boot from the raid partition or can do you need a 3rd disk to boot from? can you do it softwre only or do you need hardware?

 

I wouldn';t mind learning about RAID, but having a 2nd disk in the machine that only gets powered up and mounted during backups seems like an easier solution.

[paul]

raid is not a replacement for backups.

yes you can boot of a raid drive .. although it can be tricky.

 

software raids are easy to setup (I've got a howto)

 

if one drive fails you CANNOT boot from the single remaining drive unless you use siftware like un-raid (which is a pain)

 

in situations like this I have duplicate drive, and run a nightly cron to rsync the data .. you can even install grub on both drives, so if one fails the other one is bootable

[papaschtroumpf]

I thought that that the idea *redundant* RAID was to allow you to keep going if one drive failed.

 

It seems that the dual disk solution is what I need anyway. Also in case soemthing really bad happens that corrupts the data, an "offline" backup is more likely to be safe.

I don;t want to backup over the network, but a disk in the same machine that gets unmounted and powered down should be safe enough (short of the case catching fire!)

 

 

I have a script that does basically that. it uses cp and not rsync, although I might change it to use rsync as it seems more efficient and has a better handling of "exclude" options

[paul]

I use external usb drives ... tha way even if the case catches on fire I'm good :)

 

I also have a rotation policy for the external HDDs

[Gowator]

I thought that that the idea *redundant* RAID was to allow you to keep going if one drive failed.

 

It seems that the dual disk solution is what I need anyway. Also in case soemthing really bad happens that corrupts the data, an "offline" backup is more likely to be safe.

I don;t want to backup over the network, but a disk in the same machine that gets unmounted and powered down should be safe enough (short of the case catching fire!)

 

 

I have a script that does basically that. it uses cp and not rsync, although I might change it to use rsync as it seems more efficient and has a better handling of "exclude" options

Well it depends on the type of RAID and its implementation.

 

Personally I do the same as Paul.... A turned off and not normally connected USB hard drive in the cupboard though and I have well over a TB of media so I select what to back-up.... the hard drive is a standard one in an enclosure so even in a dire emergency it can be taken out of the enclosure and connected.

[pmpatrick]

The problem with the mirroring type of raid is that if something goes wrong on the first hard drive, the error will be copied to the second hard drive almost immediately. For example, if you erroneously delete all your media files on drive 1 then drive 2 media files will also be deleted. The redundancy of mirror type raid is designed to protect you from hard drive failure, not from your own mistakes or others mischief. That's why people say it's not a substitute for a backup.

[ianw1974]

I wrote a tips and tricks on howto software raid in mandriva. I use this at home, in case one disk dies, I still have the other to boot, then replace the old drive and reactivate the mirror.

 

Here it is:

 

https://mandrivausers.org/index.php?act=ST&...=22&t=30591