[CentOS] Booting Software RAID

[m.roth at 5-cent.us]

Paul Heinlein wrote:
> On Thu, 30 Jan 2014, m.roth at 5-cent.us wrote:
>
>> Eight years ago, I wrote an article for SysAdmin, suggesting a
>> straight partition for /boot and root, and lvm for /home and /var,
>> and /usr. These days, I might say RAID 1 for /boot and /, and RAID
>> or not for swap, and another raid partition for everything else:
>> home, other data directories....
>
> That's pretty much in line with our practice for standalone machines:
>
>   * /boot -- RAID 1
>   * /     -- RAID 1
>   * /srv  -- RAID 1 or 5, and it may not even be broken out
>   * /home -- NAS (RAID 10, if it matters)
>
> For VMs, there's just swap and /.
>
>> At work, we're going to not more than 500G for /, but I'm thinking a
>> lot less: I just rebuilt my own system at home, and gave / 150G, I
>> think, and I have /var there (though I'd put web stuff elsewhere
>> than on /).
>
> A RAID 1 of (relatively) inexpensive 80GB or 120GB SSDs are my default
> for swap and the root filesystem. Larger /srv filesystems, and the NAS
> holding /home, still require spinning platters on our budget.

That's a *huge* amount of swap - we settled, years ago, and I think
upstream recommends, 2G. Now, around here, our servers have
*significantly* more than 2G, and if we see anything in swap, we know
something's wrong.

       mark