[CentOS] raid 5 install

Sat Jun 29 07:13:24 UTC 2019
Simon Matter <simon.matter at invoca.ch>

> IMHO, Hardware raid primarily exists because of Microsoft Windows and
> VMware esxi, neither of which have good native storage management.
> Because of this, it's fairly hard to order a major brand (HP, Dell, etc)
> server without raid cards.
> Raid cards do have the performance boost of nonvolatile write back cache.
>  Newer/better cards use supercap flash for this, so battery life is no

The supercaps may be more stable than batteries but they can also fail.
Since I had to replace the supercap of a HP server I know they also do
fail. That's why they are also built as a module connected to the
controller :-)

As for the write back cache, good SSDs do the same with integrated cache
and supercaps, so you really don't need the RAID controller to do it

> longer an issue
> That said, make my Unix boxes zfs or mdraid+xfs on jbod for all the
> reasons
> previously given.

Same here, after long years of all kind of RAID hardware, I'm happy to run
everything on mdraid+xfs. Software RAID on directly attached U.2 NMVe
disks is all we use for new servers. It's fast, stable and also important,
still KISS.