[lug] RAID 5 Question

Sean Reifschneider jafo at tummy.com
Fri May 25 17:48:14 MDT 2007

On Fri, May 25, 2007 at 03:28:57PM -0600, Zan Lynx wrote:
>> RAW RAW RAW PARITY, then you can lose one drive.

Just to be canonical, RAID-5 stripes the parity data, so that all drives
contain both raw data and parity information.  This is the "improvement" of
RAID-5 over RAID-4, because it means that there isn't a single drive that
has parity, which can make that drive a bottleneck for parity updates.

>Downside is that the array slows down to the speed of USB-2.

Yeah, but USB-2 is probably faster than a single drive in your array.  I
know that my use of USB-2 external drives has really shown no appreciable
performance difference from a direct SATA connection.

 "If you're really us, what UDP port do you use?"  "TFTP, dudes!"
                 -- Scott Kleihege, 2005
Sean Reifschneider, Member of Technical Staff <jafo at tummy.com>
tummy.com, ltd. - Linux Consulting since 1995: Ask me about High Availability

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