graid3 or graid5? with or without gjournal?

[Jerome Herman]

On 26/07/2011 08:48, DA Forsyth wrote:
> Hi all
>
> I am busy putting together a new server.  I want to avoid using the
> motherboards raid 'hardware' (intel matrix raid) and rather do it all
> in software so if anything goes wrong with the motherboard, the
> drives can work in some other box.
>
> I have 4x 1TB drives available for the main data array.
> graid3 can only use 3
> graid5 can use all 4, but is it production ready?
> any ideas?
Take everything I say with a grain of salt, I am still testing these 
kinds of setup.

I do not know about graid5, but gvinum is very slow when used in a raid5 
config, this is especially true for meta intensive operations, such as 
rsync.
graid3 should be even worse as Raid3 is supposed to work on the octet 
level (In software mode it actually writes in sector, but I do not know 
how it computes).
Another thing that strongly encourages me to stay away from graid3, 
graid5 and gvinum raid5 is that the examples were removed from the handbook.

I ended up using gvinum in a mix of concat and stripe. Not as efficient 
in terms of data space, but much much faster.
In your case for example I would cut all the drives in two subdisks and 
go for a RAID10 setup.

>
> The advantage of using graid3 at this point is that the extra 1TB
> drive I have can then go into the backup server which needs more
> space anyway.
>
> Having suffered data loss on the previous raid5 (intel matrix) array
> when UFS went bananas due to one drive failing, I am looking at
> solutions/preventatives.   Will gjournal be useful?
>
> Thanks
>
>
> --
>         DA Fo rsyth            Network Supervisor
> Principal Technical Officer -- Institute for Water Research
> http://www.ru.ac.za/institutes/iwr/
>
>
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