Hard Disk IDs in Linux

Dan Egli ddavidegli at gmail.com
Thu Mar 14 01:24:03 MDT 2013


*You do have a point there. Safety of data is important. This machine will
be for work. Frankly I'm not the one who wants that big of a machine.
That's my boss. I am trying to tell him that the odds of us needing to fill
even 1/3 of that are practically nil in the next five years, but I'm sure
you all have had superiors who simply don't listen. They get an idea of
what they want and that's what they expect, no matter what the truth of the
matter is. I'm still trying to convince him to go with a much smaller
machine, but we'll see what the outcome is.*

* *

*I personally DON'T need 120 TB in my home. A simple home server with a 4
Drive RAID6 is exactly what I had planned on for MY server. *

* *

*As to file system, that was planned on ZFS unless you guys has a better
idea. As to the connection, it's probably going to be iSCSI. I have not
nailed that one down because I'm still hoping to get a smaller machine out
of my boss, and if I do I'm going to look into what's available at that
size. I'd really like to convince him to just go for a full tower PC with
like eight to twelve disks, but I don't know if I can convince him that
it's a more efficient way to go. He's really stubborn.*

* *

*Thanks for all the help so far guys.*

* *

*--- Dan*


On Tue, Mar 12, 2013 at 9:35 PM, Michael Torrie <torriem at gmail.com> wrote:

> On 03/12/2013 12:28 AM, Dan Egli wrote:
> > The thing I was trying to accomplish with the larger array was the large
> > amount of disk space available. I.e. if I fill the enclosure with 32 4TB
> > drives and make a single raid 6 I wind up with 120TB of available
> storage.
> > On the other hand, if I was to make four equal array of 8 drives each in
> > raid 6 then I loose not just 8TB total but 8TB per array, or 32TB total,
> > leaving me with 96TB, which is still a good amount of storage, but also
> > quite literally only 75% of the disk capacity. If anyone knows a good way
> > to increase the disk capacity availability to raise it above 75%
> > (preferably back up to the 90% range) I'm all ears.
>
> The point of RAID is not to give you a large amount of storage, first
> and foremost.  I use it knowing I'm giving up raw storage for this
> security.  So forget about 90%.  You simply can't get 90% usable storage
> while still having any amount of realistic redundancy and security RAID
> provides.
>
> Personally, if I had that many disks, I would do RAID10.  Basically
> that's striping across pairs of RAID1 disks.  Or use sets of 4 disks in
> a RAID-6 setup, and stripe across them.  Same efficiency as RAID10, but
> you can lose up to 2 out of any 4 disks.  Either way, 50% efficiency,
> but I'd sleep way better at night.
>
> With 32 disks the failure statistics mean you will be replacing disks on
> a fairly regular basis.
>
> Now I'm not sure why you need 120 TB in your home.  Or is this disk
> array of yours going to be for work?  Are you going to put the disks in
> a fibre channel array?  iSCSI?  Are you going to use some sort of fabric
> to connect the drives to your computers?  What file system do you plan
> to use?
>
> /*
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> Don't fear the penguin.
> */
>


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