[CentOS] RAID help

Tue Dec 14 19:06:06 UTC 2010
Ryan Wagoner <rswagoner at gmail.com>

On Tue, Dec 14, 2010 at 1:49 PM,  <m.roth at 5-cent.us> wrote:
> Jason T. Slack-Moehrle wrote:

> Only if you want to mirror the boot partition.
>>
>> 3. Create other mount points I might want i.e swap, /home, etc
>> 4. Create RAID1 out of these partitions
>
> Only if you want each directory RAIDed. DO NOT mirror swap. Bad idea.

You want to mirror swap. If a drive fails your swap immediately goes
offline. If an application had memory in swap it is now lost.

>> A few questions:
>>
>> 1. This system support 16gb of RAM. I have 9gb in it, but I will max it
>> out over the next few months as I find great deals on RAM, what should my
>> SWAP space be? I recall a long while ago that SWAP should match physical
>> RAM.
>
> Nope. Received Wisdom said 2-2.5 times RAM. However, in these days of in
> insanely huge amounts of RAM, it's not really important. At work, I just
> make swap 2G for everything (and trust me, we've got servers that make
> your memory look piddly).

I do the same 1-2GB for swap. The servers hardly every touch swap as
they have enough memory.

>>
>> 2. Any reason I can't just create a single mount point taking up the
>> entire drive and RAID1 the entire thing? Can anyone recommend some ideal
>> mount points and sizes?
>
> Nope, no reason.
>>
>> 3. What should I account for if my /var/www/html will be very large?
>
> My manager here doesn't like LVM; but if it were me, I'd make that
> /var/www an LVM virtual partition. That way, you can always add another
> drive and thow more space into it.

I only use LVM if I need the features if offers. Otherwise it is just
extra overhead.

Ryan