[Gllug] Discs for a RAID1 pair

Chris Bell chrisbell at chrisbell.org.uk
Mon Jul 4 18:07:50 UTC 2011

On Mon 04 Jul, Alain Williams wrote:

> > either combination? Should I try to disable the disc cache as a precaution?
> Hmmmm, I tried that a couple of years ago, for the disks in the mirror I did
> this:
>     hdparm -W 0 /dev/sda
> What I found was that it made the system slower - no, I did no measurements, but
> it really felt slower.
> The other thing, more serious for me, was that it caused the mirror to break when I
> got one of the disks dropping out with a not ready error (or something). Since they
> were 1TB disks they took some time to be resynched. 

   Thanks for all the replies, what I was most worried about was "disk not
ready" problems with green discs, and data written to and then held in cache
until actually written to disc, with changes possibly copied in the wrong
order. A slight delay as a disc spins up to full speed again would not be a
great problem to me. Agreed on the UPS, must get some replacement batteries.
The local mains power distribution cable here is no longer reliable.

Chris Bell www.chrisbell.org.uk
Microsoft sells you Windows ... Linux gives you the whole house.

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