Re: [gentoo-user] Software RAID Advice Needed

[Ognjen Bezanov <ognjen@mailshack.com>]

kashani wrote:

> Doug Brown wrote:
>
>> My mobo's chipset (nvidia nf 4) doesn't support raid real well, and I 
>> have read that Linux Software raid is very good.  I am getting ready 
>> to install Gentoo 2005.1 64bit real soon (I am new to Gentoo), and I 
>> was wondering what  types of raid it supports.  I know it supports 0 
>> and 1, but I am more interested in raid 0+1 and 1+0. 
>
>
>     Linux software raid is capable of doing all the usual stuff as 
> well as RAID 0+1 or 1+0. I'd want a RAID 0 stripe of mirrored RAID 1 
> sets rather than mirroring two RAID 0 sets, but my requirements may 
> not be yours.
>
>     Assuming this is a small home system I'd go with RAID 5 with maybe 
> a hot spare if I have more than four drives in a normal server setting 
> where reads happen more often than writes. That's more space with 
> comparable performance for anything you're likely to be doing. If you 
> really need the performance spend the money on a real RAID card with 
> local cache. The difference is night and day.
>
> kashani

RAID 5 support in Linux is good. I have been using RAID-5 for my home 
fileserver (4x40GB IDE disks) and it has worked flawlessly, and has been 
a lifesaver when one of my drives failed.

I have a page devoted to setting up RAID on linux  quickly (gentoo and 
debian) , you can find it at http://ziva-vatra.dnsalias.com/~ognen/ 
under "Software RAID5 Project".  And if you want more info look at the 
"RAID Overview" Section.

Linux kernel 2.6 has added support for new RAID levels (including 
RAID6)  but some people are saying that other RAID Implementations (such 
as RAID-5) have better performance on the 2.4 kernels.

I have found Linux Software RAID very useful and reliable. While 
probably being beaten in the performance  area by hardware 
implementations, I have to say it does do the job well, and I have no 
issues using it both in my home server and in Commercial implementations 
(have used RAID-5 and RAID-1 software with 5 SCSI drives on a dual PIII 
Gentoo LTSP server, it worked well, but there were issues regarding the 
SCSI hardware (like no hotplug support for the disks) ).

Google about, and look at the gentoo-wiki site.

Essentially it depends on what you are looking from your RAID setup. For 
me it was re-using componets I already had and price (it cost me a total 
of £8 to build my RAID Setup). Performance was not an issue because my 
two 10mbit networks (one wireless @ 11mbit) were unlikely to push the 
RAID performance to its limits.



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