Re: Software RAID5 with 2.6.0-test

Chuck Campbell
2003-10-22T15:24:23Z

On Tue, Oct 21, 2003 at 09:36:39PM +0000, bill davidsen wrote:
> In article <yw1xu167kbcw.fsf@users.sourceforge.net>,
> =?iso-8859-1?q?M=E5ns_Rullg=E5rd?= <mru@users.sourceforge.net> wrote:
> | Bill Davidsen <davidsen@tmr.com> writes:
>
> Unfortunately my experience is with either the cheap motherboard ones I
> get for free and the IBM ServRAID controllers which are kind of in the
> "more than that" category. The benefit of the m/b ones is that with
> RAID-1 you will get a boot if the boot drive fails. Period. Unlike
> optimal RAID-1 which will read mirrored data from any non-busy drive,
> the cheap ones seem to do fail-over only, and read the second drive
> only if the first fails, or even require both drives to be on the same
> cable, ensuring that the bus will be busy when either drive is busy.
> They do buy reliability, however, so there are places where they are
> very cost effective.

In this situation that you describe, how does one recover from this? Do
these cheap motherboard RAID-1's do an autorebuild when the failed
disk is replaced? (Obviously not hot-swap, but on reboot to replace
the drive).

>
> The IBM controllers are everything you ever wanted in a controller. It
> supports four SCSI busses for bandwidth, all the RAID types including
> 5e, and it has Linux config software so you can do most reconfigures on
> a running system. I would choose them over anything else I've personally
> used, mainly Adaptec and PERC. They are really great for multi-TB
> storage systems.

Do they compare favorable against 3Ware as well?

> Anyone who says that any one solution is best for everything is clearly
> misguided, but I do think that for many midsize applications that
> software RAID is the most cost effective solution, and vs. moderately
> priced controllers very likely to be the higher performance solution as
> well.

Is this statement true, in your opinion, for RAID-5 as well?

-chuck

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