OK that is for hardware level RAID. I had thought that you would offset
the extra processing time by being able to write less to each drive.
Now does anyone know how much overhead Windows 2000/2003 software RAID 1
on dynamic disks produces over hardware level RAID 1?
I am assuming it would be substantial.
Goran Jovanovic
The LAN Shoppe
> -----Original Message-----
> From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
> On Behalf Of Pete McNeil
> Sent: Wednesday, March 16, 2005 11:43 AM
> To: Goran Jovanovic
> Subject: Re[2]: [sniffer] Moving Sniffer to Declude/SmarterMail
>
> On Wednesday, March 16, 2005, 11:25:46 AM, Goran wrote:
>
> <snip/>
>
> GJ> I guess this is going against what I think should be happening. In
a
> GJ> RAID 5 array the write to the drives is broken into many smaller
> writes
> GJ> along with the data protection/CRC info and then those writes are
> GJ> written to different drives. It seems to me that it should be
faster
> to
> GJ> do a bunch of small writes rather than 1 big write.
>
> GJ> What am I missing?
>
> Writing data to a single hard drive takes x amount of work.
>
> Writing data to more than one drive takes x+y amount of work where y
> is breaking up the data into chunks.
>
> Writing data to a raid 5 takes x+y+z amount of work where y is
> described above and z is calculating a CRC stripe which must now also
> be saved to a hard drive.
>
> So, writing to raid5 is relatively very expensive compared to writing
> to a plain old hard drive, or a less complex raid (such as mirroring).
>
> IMO, the best strategy for email servers is to use an ordinary, single
> fast HD for all spool operations, and place mailboxes on a raid 1 or
> raid 10.
>
> Hope this helps,
>
> _M
>
>
>
>
>
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