Am 02.03.2014 00:42, schrieb Chris Murphy:
On Mar 1, 2014, at 4:26 PM, Chris Murphy <lists(a)colorremedies.com> wrote:
>
> On Mar 1, 2014, at 2:16 PM, Matthew Miller <mattdm(a)fedoraproject.org> wrote:
>
>> On Fri, Feb 28, 2014 at 11:29:30PM -0700, Chris Murphy wrote:
>>> - There needs to be a mandate to remove features from custom partitioning
>>> that quite frankly don't make sense like rootfs on raid4, raid5 or
>>> raid6. OK maybe raid5. But not raid 4 or raid 6. There are other
>>
>> Okay, I'll bite. Why not rootfs on raid6?
>
> It's pathological. There are too many simpler, faster, more resilient options
considering rootfs at most isn't bigger than the average SSD: Two or three SSDs +
n-way mirroring. RAID 10. Or RAID 1 + linear + XFS for deterministic workloads.
Those three examples are simpler, more resilient, easier to configure and maintain,
perform better, with faster rebuild times than RAID 6 which also has a high
read-modify-write penalty. I left that part out.
yes, but RAID6 allows a disk-fault *while* rebuild the RAID after the first one
RADID 10 *may* do the same if the *right* second disk fails
in real life disks are mostly identical old and in case one fails the chance
that anotehr one fails within a short timeframe is high and the rebuild makes
it even more likely
frankly i saw SAN configurations where after remove 20 disks the system said
"if now anotehr one fails *we maybe* have a problem" and in real life the
performance penalty is meaningless compared to a complete fail of the array