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Re: RAID1 + Ext3 + Automatic Power Resets



On Friday 20 September 2002 14:37 pm, Mr mark ennis wrote:
> I am testing EXT3 as a filesystem for a server whose
> power supply is failure prone.
>
> In order to do the test, I have a lever that I can
> control from PC1 that can press the reset button on
> PC2. PC2's reset button is automatically pressed once
> every 120 seconds (the boot sequence on PC2 takes 80
> seconds).
>
> While PC2 is booted, PC1 directs email and web
> requests at PC2, so that the PC2 disks are busy
>
>       PC1 o=lever==== PC2 (Raid1, Journaled EXT3)
>
>        ------network-----
>
> PC2 setup:
>         .2* RAID-1 (mirrored) IDE Disks (md - s/w

If you're using IDE drives make sure the write-back cache on the drives are 
disabled. Flushed log data may only be in the drives cache and not on the 
platter when you flip the switch, causing loss of data for that transaction.

hdparm -W 0 /dev/hda
hdparm -W 0 /dev/hdb

Jeremy





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