# ZFS and RAID question



## fred974 (Jul 15, 2014)

Hello everyone,

I just acquired a Dell PowerEdge R610 and it comes with a Perc6/i SAS controller and four SAS disks. Could anyone here tell me whether if I install FreeBSD RAID-Z2, if the disks are hot-swappable? Will I need to shutdown the system to change the disk if something happens? Am I better off using the SAS RAID controller instead of the software RAID? Is the performance better on the hardware RAID?

Thank you in advance.

Fred


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## usdmatt (Jul 16, 2014)

Boot up off the live CD, plug a disk in and see what happens 

I personally would expect the hardware RAID with UFS to out-perform ZFS. It just depends on how much you want the checksumming, snapshots, ability to access the data in machines that don't have a Perc6, etc.

Apparently the controller supports hot-swap (http://accessories.dell.com/sna/product ... u=341-6064). The issue will be whether it passes unconfigured disks to the OS (like an HBA), or if you'll end up having to initialise the disks in the RAID BIOS somehow in order for them to appear in FreeBSD.


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