On Mar 1, 2014, at 5:44 PM, Reindl Harald <h.reindl(a)thelounge.net> wrote:
Am 02.03.2014 01:36, schrieb Chris Murphy:
> On Mar 1, 2014, at 4:51 PM, Reindl Harald <h.reindl(a)thelounge.net> wrote:
>
>> 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
>
> If you need two disk failure tolerance use n-way mirroring with three disks, anaconda
supports this
and if you need failure tolerance *and* performance?
You need better rootfs performance than what's provided by SSD?
yes, then use commercial SAN storages…
OK, but it sounds expensive and demeaning. Yet, I'll grant that it's more sane
than rootfs on software RAID 6.
Chris Murphy