Re: Disks mirroring

Tech-Archive recommends: Fix windows errors by optimizing your registry

From: Eugene Tan (insights-[dropthis)
Date: 11/29/04 

Date: Mon, 29 Nov 2004 16:35:58 +0800

hi,

>From your limited info it appears you are saying you have configured
software mirroring from DiskManager, is this correct?

First, I agree with Kevin that it is safest to use hardware mirroring.
This means the mirroring is done completely on the hardware adaptor
which has its own CPU and memory. Less difficult but still risky is
software mirroring where the processing is done by the drivers using
the main CPU - these types are usually very low cost adaptors or on
the mainboard with IDE/SATA RAID.

The resyncing problem is probably caused by some timing issue -
the power is cutoff during shutdown before data is properly written to
the mirrored HD.

To fix this, you need to do something to enable more time for writing.
Options include disabling the auto-poweroff (show "Safe to poweroff
the computer now" screen - sorry I don't know where to find this info
right now), or disabling the write cache of your HD/array, or getting
HDs with smaller caches - nowadays, many IDE HD have 8MB cache
which might just take too long to writeback the data in a software RAID.
Look for something with only 2MB.

If you were testing the reliability of recovering from a failure of the
first
HD (you removed the 'good' mirror-pair), then you first need to prepare
an Emergency Recovery Disk, and keep this updated. You'll need it to
recover with a good mirror-pair that may be out of sync.

Good luck.
Eugene Tan

=========================
"Marek Staniewski" <marek.staniewski@derco.com.pl> wrote in message
news:eHMkhJM1EHA.4028@TK2MSFTNGP15.phx.gbl...
> I have set the mirror of my system disk.
> It works fine but when I reboot the serwer (SBS2003) then the mirrored
disks
> need the sychchronizing.
> It takes about 1 hout to synchronise.
>
> I tried also to start the system by disconnecting first disk from the
> mirror.
>
> The system does not start and products a message as follows:
>
> "
> Windows could not startr because the following file is missing or corrupt:
> Windows root/system32/ntoskrnl.exe
> Please reinstall a copy of the file above
> "
>
> In my Disk manager the
> Disk 0 is an IDE disk and the DISK 1 and Disk2 are mirrored system disks
>
> Can anybody give me some instruction how to make the mirror working
> properly?
>
> Marek Staniewski
>
>
>
>

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