5.8TB RAID5 SATA Array Questions - UPDATE

Edgar Martinez emartinez at crockettint.com
Fri Apr 22 09:46:08 PDT 2005



So, after a soild chunk of life has fully been drained from me.here are
several conclusions.obviously open for discussion if anyone wants to pick my
brain.(yes we reduced our array size.you'll see why)


As much loved as BSD is to me.it simply just isn't up to the challenge at
all.its far too difficult to get in a properly working state.and the
limitations imposed are just too difficult to overcome easily.


I ended up using Ubuntu which not only had all the driver support to all the
devices and controllers.but also had little to no problem getting the system
installed properly.It however does not like/want to boot to the array.so I
installed additional drives (Seagate sata) and created a mirror (300GB) for
the system to live on and bring up the array (/dev/md0) using mdadm.overall
it was easy and nice.there are several caveats left to wrestle with.


Currently although the 3ware controller can create a huge 4TB raid5 array,
nothing exists that I am aware of that can utilize the entire container.
Every single OS that exists seems to all share the 2TB limitations..so while
the BIOS can "see" it.everything else will only see 2TB..this includes NFS
on OSX (which don't get me started on the horrible implementation mistakes
from apple and their poor NFS support..i mean NFSv4 comeon! Why is that


So to get past Ubuntu's 2TB problem, I created 2xRAID5 2TB (1.8TB reporting)
containers on the array.and then using software raid.created 1xRAID0 using
the 2xRAID5 containers.which create 1xRAID0 @4TB.


So.samba allows clients to "see" <2TB and FTP also allow for <2TB..this is
probably the most complicated.and yet simple thing I can say I have done.


Utterly horrible.probably the WORST half-assed installation imaginable.in my
honest opinion.here are my desires.


Create 1xRAID5 @ 4TB.install the OS TO the array.boot to the array and then
share out 4TB via NFS/SMB.was that too much to ask?? Obviously it was.


So in response.I can modified the requirements.


Create 1xRAID5 at 4TB...install an OS TO a 1xRAID1 at 300GB...BOOT to the
RAID1..and SHARE out the 4TB.


Any one else think they know of a better method??



From: Nick Pavlica [mailto:linicks at gmail.com] 
Sent: Friday, April 15, 2005 12:15 PM
To: emartinez at crockettint.com
Cc: Dan Nelson; Nick Evans; Benson Wong; freebsd-questions at freebsd.org
Subject: Re: 5.8TB RAID5 SATA Array Questions


On 4/15/05, Edgar Martinez <emartinez at crockettint.com> wrote:

OK...so now we are going into some new territory...I am curious if you would
care to elaborate a bit more...I am intrigued...if anyone wants me to do
some experiments or test something, let me know...I for one welcome any 
attempts at pushing any limits or trying new things...

I would help do some testing but I don't have any storage that large at the
moment.  I curious how 5.4RC2 or > handles very large volumes.   Have you
already tried fdisk, newfs ?


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