Re: What layout with 6x2TB, Intel Atom?

[Steven Haigh <netwiz@crc.id.au>]

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On 5/02/2013 8:12 AM, Roman Mamedov wrote:
> On Mon, 4 Feb 2013 20:27:42 +0000
> Mathias Burén <mathias.buren@gmail.com> wrote:
>
>> I read that the far layout gives faster read performance compared to
>> standard RAID1 in a 2 HDD array, so that's why I used it. I then
>> created yet another RAID10 f2 layout of the 3x 2 disk RAID10 volumes,
>> giving me /dev/md124. Filesystem doesn't matter, I need something
>> that's stable with good performance over the RAID set.
>> I just realized that out of 12 TB raw space I now only have 3TB
>> available, heh. So I suppose I'm going for a different layout.
>>
>> Any opinions?
>
> Hello,
>
> Why won't you even consider RAID6? To me it seems like the perfect choice,
> given the details you described (mostly reads, large files, few clients).
> And the disk count is perfect, not too few and not too many, so to say :D
>

I was going to say the same. I run a 4 x 2Tb SATA RAID6. The read speeds 
will *easily* saturate GigE. Random seeks slow things down quite a bit - 
but you'll get that with any setup except SSD.

If its mainly sequential reads, then RAID6 will be fine.

And as I know someone will ask... Why 4 drives in RAID6? Firstly, you 
still get the redundancy of surviving 2 drive failures - but also when I 
start to run low on space I can easily add another 2Tb disk and reshape 
to 5 drives, then 6. My chassis has 8 x SATA hot swap bays - 2 x 80Gb 
RAID1 leaving the other 6 for the RAID6. By the time I fill up 6 x 2Tb 
drives, there will be other cheap multi-Tb drives to use.

-- 
Steven Haigh

Email: netwiz@crc.id.au
Web: http://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897
Fax: (03) 8338 0299


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