[mythtv-users] Where are those new 1TB drives?

Stef Coene stef.coene at docum.org
Mon Mar 12 08:06:24 UTC 2007

On Sunday 11 March 2007 23:09, Dan Ritter wrote:
> On Sat, Mar 10, 2007 at 05:23:30PM -0700, Brian Wood wrote:
> > RAID5 is a good compromise between redundancy and capacity. It does
> > have a bit more overhead than RAID0 or RAID1 but that's really not a
> > problem with any machine made in the last decade. You need a minimum
> > of 3 same-size drives (or at least same-size partitions), so with the
> > drives you describe you would use both 250s and a 250GB partition on
> > the 350 for a total of 500GB storage. That leaves some left on the
> > 350 for an operating system, swap, and possibly a boot partition.
> Myth users generally like RAID 5 because:
> - it's relatively cheap. You lose the capacity of 1 drive in N,
>   usually 1/4 or 1/5.
> - the data is not very expensive (record another showing)
> - the data is not very expensive (rip it off the DVD again)
> - the data is not very expensive (no one is paying you to do
>   this)
> For many applications, though, RAID 5 is a bad idea.
All the RAID talk on this list is fun to read.
But "real" enterprices raid systems are using battey backed-up read and write 
caches.  And ones you have these, the raid level doesn't matter anymore.  
Performance is allmost the same for all raid levels, so raid5 is the best 
choice because of the cache.
Do you know that they changed the cache algorthm some time ago so you get the 
_same_ performance with _halve_ the cache size ?

Mhh, I like 4gbit fiber attached 15k fiber disks and 4 GB battery cache .....


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