RAID6? (was Re: Anyone Actually Using Virtual Linux Servers?)

[Dan Ritter]

On Wed, Sep 12, 2007 at 08:56:45AM -0400, Derek Atkins wrote:
> Do you prefer a hardware RAID card over Linux S/W RAID?
> 
> I would think that at least with S/W raid you could add disks or
> change the disk sizes to get additional space over time?

The better high-end RAID cards also allow you to add disks and
change disk sizes.

However, my opinion is that hardware RAID is a needless expense
for the vast majority of home and desktop systems, and even for
most servers -- anything that doesn't specifically need big or
fast storage.

Right now, I buy desktop boxes with pairs of 400-500GB disks, which I
put in software RAID-1. Then they get backed up over the network (at
the office) or to an external disk (at home).  The RAID-1 is largely
for convenience: when a disk fails, I don't keep anyone waiting while
I find the right backup. Most servers get the same treatment.

Big storage usually means important data. LVM over RAID-1 pairs
or RAID-10 is appropriate there, and in a big system, the
expense of a RAID card isn't too huge a fraction of the total
cost.

Fast storage may or may not mean important data, but for most of
the data sets we use, more RAM and more spindles at higher
speeds (15K SCSI disks) make the most difference. RAID-1 for
system disks. 

Everything needs a UPS as well as a data backup.

-dsr-

-- 
Every time you give up a right, the terrorists win.

http://tao.merseine.nu/~dsr/eula.html is hereby incorporated by reference.

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