[CentOS] parted usage

Wed Jan 12 01:39:47 UTC 2011
John R Pierce <pierce at hogranch.com>

On 01/11/11 5:34 PM, aurfalien at gmail.com wrote:
> On Jan 11, 2011, at 2:06 PM, Steve Thompson wrote:
>> On Tue, 11 Jan 2011, aurfalien at gmail.com wrote:
>>> I'm attempting to use parted to create a partition on a 28TB volume
>>> which consists of 16x2TB drives configuired in a Raid 5 + spare, so
>>> total unformatted size is 28TB to the OS..
>> I don't know the answer to your parted question, but let me be the
>> first
>> of many to express horror at the idea of using RAID-5 for such a large
>> volume with so many spindles, even with a hot spare. The rebuild
>> times are
>> probably going to be days, and the chance of a second spindle
>> failure in
>> that time is high enough to make it dangerous. Use RAID-6 at least.
> Hi Steve.
> I went with Raid 6 + spare.
> I'll force a failure (that is, once I get past my parted issue) and
> let you know rebuild times

I wouldn't do that if read/write performance is important during the 
possibly several day rebuild times.  a degraded raid6 can be really 
really slow until its fully rebuilt.

I personally prefer using RAID10 for just about everything, except maybe 
a bulk nearline store, and those will be raid5 or 6 with no more than 
6-8 disks per raidset, if I have more spindles, I do raid 5+0 or 6+0 
(eg, stripe two raid5 or raid6 sets).    disks are cheap.   time is money.