# FreeBSD 7.2, ZFD software raid 5



## julo (Aug 24, 2009)

Hello,

I have 3 same (empty) HDDs and I would like to install the ZFS software RAID5 on it. 
Is it possible create RAID5 during the setup a install BSD to it? 
How should I create swap partitions on my HDD? 
I think it is better to have the swap partition out of the SW raid(or not?) because of performance. But if I create the swap for example on first drive, its free space won't be equal to free spaces on other drives so I think that RAID5 won't work...or maybe yes? Or is it better to create the same sized swap partition on each drive and create RAID5 on the rest same sized free disk spaces?

Thanks a lot for the replies


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## phoenix (Aug 24, 2009)

julo said:
			
		

> I have 3 same (empty) HDDs and I would like to install the ZFS software RAID5 on it.
> 
> Is it possible create RAID5 during the setup a install BSD to it?



sysinstall, the default installer for FreeBSD, does not yet support any of the fancy filesystems or GEOM features.  IOW, you cannot install directly onto ZFS.

Personally, I'd suggest getting a 2 GB or larger USB stick, and installing the OS to that.  Once its installed, and you have booted into the OS, then you can use the ZFS tools to create a storage pool using a single raidz1 vdev, and create filesystems for things like /home, /usr/local, /var, and so on.

I'd suggest leaving / and /usr on the USB stick.  That way, if you ever need to boot to single-user mode to fix things, you'll have access to the full FreeBSD install.



> How should I create swap partitions on my HDD?



You could create 2 slices on each harddrive, and make them the same size on all three harddrives.  s1 on each drive would be for swap (1-2 GB should be plenty) and s2 would be for ZFS.  The FreeBSD kernel will then (in essence) create a RAID0 stripe of the three swap partitions.



> I think it is better to have the swap partition out of the SW raid(or not?) because of performance.



Yes.  There's also issues with using swap files on ZFS or swap partitions on ZVols, due to the way memory management works in ZFS.


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## astadtler (Aug 26, 2009)

Remember that ZFS performance is best when it is allowed to use the whole drive as one slice.  I would recommend just using a small drive that is left over doesn't need to be very big or buy something else if you need more performance.


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