[ale] Needing to cut up server disk space

[Solomon Peachy]

On Wed, Sep 23, 2015 at 11:42:37PM -0400, Jeff Hubbs wrote:
>  * I really dislike hardware RAID cards like Dell PERC. If there has to
>    be one, I would much rather set it to JBOD mode and get my RAIDing
>    done some other way.

There's a big difference between "hardware" RAID (aka fakeRAID) and real 
hardware RAID boards.  The former are the worst of both worlds, but the 
latter are the real deal.

In particular, the various Dell PERC RAID adapters are excellent, fast, 
and highly reliable, with full native linux support for managing them.

Strictly speaking you'll end up with more flexibility going the JBOD 
route, but you're going to lose both performance and reliability versus 
the PERC.

(for example, what happens if the "boot" drive fails?  Guess what, your 
 system is no longer bootable with the JBOD, but the PERC will work just 
 fine)

>  * I foresee I will have gnashing of teeth if I set in stone at install
>    time the sizes of the /var and /home volumes. There's no telling how
>    much or how little space PostgreSQL might need in the future and you
>    know how GRAs are - give them disk space and they'll take disk space. :)

You're not talking about much space here; only 5*400 == 2TB of raw 
space, going down to 1.6TV by the time the RAID5 overhead is factored 
in.  Just create a single 2TB filesystem and be done with it.

FWIW, If you're after reliability I'd caution against btrfs, and instead 
recommend XFS -- and make sure the system is plugged into a UPS.  No 
matter what, be sure to align the partition and filesystem with the 
block/stripe sizes of the RAID setup.

(The system I'm typing this on has about ~10TB of XFS RAID5 filesystems 
 hanging off a 3ware 9650 card, plus a 1TB RAID1 for the OS)

 - Solomon
-- 
Solomon Peachy        		       pizza at shaftnet dot org
Delray Beach, FL                          ^^ (email/xmpp) ^^
Quidquid latine dictum sit, altum viditur.
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