[CentOS] RAIDs and JBOD?

James Bensley jwbensley at gmail.com
Wed Nov 11 00:07:21 UTC 2009

Thanks all for the promptness of your responses and the details you
have provided it is greatly appreciated.

Since this is a home media server performance isn't imperative and
mirroring and RAID 10/0+1 are too expensive so I am going to use my
three existing drives of different manufactures as they are all
reasonably new (each was purchased at different times this year) and
throw in two more giving four drives for data and one for parity. That
will suffice in terms of storage size (4TBs) and a ratio of four data
drives to one parity is as far as I feel comfortable in terms of
hardware redundancy.

I have read a few articles about mdadm and I have devised the
following strategy in my head and am looking for some confirmation of
its theoretical success:

Two of my existing three drives are full of data. I will purchase two
more drives to go with my existing blank drive and set them up as a
RAID 5 > copy my existing data on to the new file system one drive at
a time and after each drive has been copied I will add said drive and
use mdadm --grow to then incorporate that drive into the RAID before
adding the next drive. Can anyone point out a flaw in this plan or
more preferred method for doing this, or have I, dare I say it, got it

Also I was initially going to get a PCI-E SATA card to connect up all
these drives and use mdadm to make a software RAID, for this
particular setup is that ill advised or do people think this will
suffice (simple because my budget is low and hardware RAID controller
cards are more expansive, in my experience but if you know of a good
bargain I'm all ears!). Just quickly, this brings me back to the issue
of a hot swappable drive. Up time isn't critical as its a home server
so I don't believe a hotspare is needed, in the event of a drive
failure I can shutdown the server and fire up single user mode and
have the RAID file system dismount and then replace the failed drive
and rebuild the array, is this correct?

Thank you for you time guys it has been very much appreciated.

James ;)

Joan Crawford  - "I, Joan Crawford, I believe in the dollar.
Everything I earn, I spend." -

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