Re: OT: harddrive addition for RAID
On 10/17/2011 5:09 PM, Raf Czlonka wrote:
> On Mon, Oct 17, 2011 at 06:12:00PM BST, Camaleón wrote:
>>> 1. does the HD need to be exactly the same as the one its being paired
>>> with ?
>>
>> Not necessarily, but you will lose the remainder difference space between
>> the smallest and the bigger of the disks. If you were referring to the
>> brand/model/serial number of the disks some people think is better they
>> exactly match (me) others think the opposite.
>
> It's not just size that matters ;^)
> If you'd like your RAID array to perform better it's always better to
> have the disks identical - cache size, speed, etc. If you have drives
> which don't match, essentially your RAID will perform as good as your
> worst drive.
Also keep in mind that with software RAID you won't be mirroring
"drives" but partitions, since you're looking to mirror your boot/system
drive. Getting your BIOS, boot loader and mdraid setup correctly so
that the surviving drive boots the system after the other fails can be
very very tricky, especially for a Linux RAID novice.
If this is what you want to accomplish, then you have a lot of reading
and research ahead of you, and likely some trial and error, along with
headaches.
Given the costs, learning curve, and "ease of use" issues, if I were
you, I'd simply purchase a good cheap real RAID0/1 card and two new
matching 500GB drives. Something like this combo:
1 x http://www.newegg.com/Product/Product.aspx?Item=N82E16816116075
2 x http://www.newegg.com/Product/Product.aspx?Item=N82E16822136073
Setting up a RAID1 set will be pretty easy with this card, and if one
drive fails the card simply boots the other automatically and writes the
failure to a log file and/or sends you an email. No hoops you have to
jump through as with mdraid. And you'll also get a nice little speed
bump due to the 128MB of cache on board. If your system is connected to
a good working UPS you can enable write caching for even better
performance. Total cost of these parts from Newegg is about
$270+shipping. All you need is a free PCIe x1 slot.
If the cost isn't prohibitive, you'll be much happier with this solution.
--
Stan
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