Re: [gentoo-user] LVM for data drives but not the OS

[Mark Knecht]

On Sat, Apr 9, 2011 at 6:33 AM, Dale <rdalek1967@×××××.com> wrote:
<SNIP>
>
> I think I am too.  Since folks know I am disabled anyway, I went to the Dr
> the other day.  The new meds aren't perfect but it is better.  When I go
> back, he may change it to another med.  He just wanted to try this first.
>  It does sort of help me to get a better grasp on things tho.  Sort of weird
> in a way.  That part is like a side effect.  :/
>
> I'm just needing to find me a good LARGE drive to put in here.  I'm checking
> out the reviews but it just seems most have issues.  May just have to buy
> one, work the stuffing out of it with a script or something to see if it
> holds up.
>
> I see some of the large drives spin slower, some a lot slower.  Given the
> density of the data, are they about as fast as a drive that spins at 7200?
>  My main drives for my OS and the large drive I already have turn at 7200
> rpms.  I'm just curious if that would be slower or because of the density of
> the data, it doesn't matter.  I get about 80 to 100Mb/sec on my current
> drives.  I have 3gbs/sec drives which is what my mobo maxes out at.  I
> thought about getting a 6Gb/sec just in case I upgrade my mobo later.
>
> My data drive mostly has audio/video stuff but does contain pictures I took
> with my camera and some documents, mostly saved web pages or OOo stuff.  My
> 750Gb drives plays audio/video stuff just fine, even the HD stuff.  I just
> wouldn't want to get a drive that is slow enough to cause pauses and such.
>
> I see newegg has 3Tb drives too.  he he he he  O_O
>
> Thoughts?
>
> Dale

Good thread Dale. I've been busy this week so I finally read the whole
thing, start to finish, this morning. Good LVM info which I expect
I'll use one of these days myself.

Personally II think one thing you might want to consider, given your
concerns about not losing important personal data, is to investigate
RAID with the same level of focus that you are doing with LVM. Instead
of buying very large drives (3TB) you can build a large RAID6 or RAID5
out of smaller 500GB or 1TB drives. Personally my home compute server,
which runs 4 copies of Windows 7 in VMWare and Virtualbox for trading
in the futures market, is set up this way:

- Five 500GB WD RAID Edition physical drives

- /boot is just a 100MB partition on /dev/sda, but I've saved more
partition space on other drives with various kernel images should
/dev/sda fail.

- Gentoo is on a 50GB 5-drive RAID1. That's a LOT of redundancy. I can
technically lose 4 drives and the system continues to work fine. For
the OS that's essentially unkillable short of someting like a power
supply failure taking out all the drives or the MB.

- /home is on a 5-drive RAID6 using 50GB partitions. That gives me a
total of 150GB storage personally for my pictures, videos, code, etc.,
and allows 2 drives to fail without losing data.

- /VirtualMachines is on a 5-drive RAID6 using the remaining 400GB on
each drive, so that's 1.2TB with redundancy of a 2-drive loss being
protected.

I then have a few external eSATA hard drives that I use for backups.
/home to one pair, /VirtualMachines to another pair.

I think if I was to set up this system from scratch again I might
consider one large RAID6 using 450GB and putting /home in one LV and
/VirtualMachines in another. The advantage would be that over time, if
my personal needs increased, I could resize the LVs more easily than
resizing the RAIDs. (Which is also possible but beyond the scope of
this thread...)

Anyway, it's just another idea about how you can use the same hardware
in a different configuration. Five 1TB drives as a RAID6 gives you
both 3TB of storage as well as far more reliability. One 3TB drive by
itself can die and everything is gone.

Congrats on your learning experience and I hope it continues to be
successful for you.

Cheers,
Mark