Re: Disk I/O slowness

Hi,

On Tue, Aug 04, 2026 at 01:27:11PM -0400, Dan Ritter wrote:
> Stefan Monnier wrote: 
> > I'd even say that raid 5/6 is very rarely the better choice.  In a sense
> > it's mostly of academic interest; in practice it's almost always
> > preferable to stick with raid 0/1/10.  In theory raid 5/6 can be a few
> > percent cheaper in some cases, but it's rarely a good tradeoff.
> > So unless you really know what you're doing I'd recommend to stay away
> > from raid 5/6.
> 
> It All Depends, and economics vs performance is a real
> consideration.

I agree. Parity RAIDs were on the verge of being forgotten, but the
choices between HDDs and various kinds of flash, and the cost of storage
peaking again, made things more interesting and complex.

Copy on write filesystems like btrfs and zfs don't suffer from the
"RAID-5 write hole" and raidz1, z2 and z3 configurations don't have a
big stigma attached other than the general advice that "mirrors will be
faster".

Thanks,
Andy