[CentOS] Re: Duplicate PV on HW RAID?

Tue Jul 29 22:12:04 UTC 2008
Rainer Duffner <rainer at ultra-secure.de>

Am 29.07.2008 um 23:04 schrieb Eduardo Grosclaude:

>
>
> On Tue, Jul 29, 2008 at 1:23 PM, Lanny Marcus <lmmailinglists at gmail.com 
> > wrote:
> Eduardo: To give you something else to consider, as an alternative:  I
> believe there was a long thread here, awhile back, about using
> Software RAID, instead of fake RAID controllers. Software RAID works
> very well, as I recall from reading that thread. Possibly look into
> changing to Software RAID. Depends on the HW RAID controller.
>
> Yes, I finally ended up installing software RAID because
> 1) I have read that, even if I installed the proper driver, Linux  
> only uses it to configure its own dm software RAID device according  
> to the BIOS conf-- is this completely true? If yes, no real  
> offloading anything to hardware anyway-- even under Windows; does  
> anybody know about this for sure?
> 2) I am very scared by non-kernel-tree-blessed modules which have  
> their own install procedures and/or updating schedule, I have been  
> bitten by this in the past.
>
> I finally did setup two 1-RAIDed identical partitions and installed  
> the system on the rest of both disks... Now my system won't boot if  
> one disk is broken, but I hope I can go rescue into the data. I was  
> formerly hoping to rely on RAID to protect the full install and  
> simplify my life, but I was discouraged away by 1) and 2).
>
> I have yet to see a real RAID controller... At what price do they  
> start off?


For two channels, there's little that is worth paying for, IMNSHO.
3Ware 8006 is only SATA-one, not SATA-II (two), which brings its own  
set of problems.
For four channels:
See www.areca.com.tw for models and use your local search engine to  
find a good offer.
It's not cheap, but you get top performance. I see that they now also  
offer a two channel SATA-II RAID controller - newegg lists it for 180  
USD. Software RAID gets more attractive every day...
I can also recommend their 8 and 12 port controllers - but as  
discussed last time, the more disks you add, the less flexible  
hardware-RAID (and Linux) get and Solaris/ZFS make more sense then (16  
disks upwards IMO).
If your storage needs are not constantly growing, Linux is OK.



cheers,
Rainer

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