# Drive concatention



## freamer (Jan 21, 2010)

Hello everyone, maybe I`ve got very primitive situation,but I just couldn`t find any concrete information on my topic.

So, I`m running freebsd 6.1 with 3 ide drives,each by 1 TB, without hardware raid.

First one is partitioned automatically, /usr is about 1000GB.

What I need to do is to merge second and third drives and join them with /usr mount point without any data loss.

Where shall I start and what program should I use?

Thanks for any upcoming ideas.


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## Ruler2112 (Jan 21, 2010)

Assuming you don't want any redundancy, read up on RAID0.  Be aware though, if one drive dies, you lose everything.

RAID5 would take the space of one drive away from your total available size, but if any single drive dies, you lose nothing.  (This is what I have running on my Linux box - 4x400gig = 1.2TB available.  I've never done it on FreeBSD though.)


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## freamer (Jan 21, 2010)

In future I plan to add more disks and I think they won`t be the same size,so this technique is not suitable?


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## freamer (Jan 21, 2010)

Handbook says how to do it with unformatted drives,but I have no right to reinstall anything. I assume that it`s only for unformatted drives.

Anyways, thank you.


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## phoenix (Jan 21, 2010)

Are you sure you want to concatenate them?  Doing so doesn't provide any redundancy, so if a drive dies, the data goes with it.

If you are sure you want to, then have a look at gconcat(8).

Otherwise, look into software RAID, like graid3(8), graid5(8) (don't think that will link correctly, as geom_raid5 isn't in the base yet, but searching for it will bring up how-tos and forum threads), and zfs().


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## freamer (Jan 21, 2010)

Okay, so here are some questions on gconcat I couldn`t resolve.

Will it destroy any data on existing drives?

If I got it right,to merge /usr with on drive 1 with 2 other I need:


```
gconcat label data /dev/da0 /dev/da1 /dev/da2
growfs /dev/concat/data
mount /dev/concat/data /usr
```


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## aragon (Jan 21, 2010)

growfs is dangerous.  I hope you have backups.


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