[CentOS] RAID help

Thu Dec 16 14:26:19 UTC 2010
Bowie Bailey <Bowie_Bailey at BUC.com>

On 12/16/2010 2:15 AM, Philix T A wrote:
> 1) RAID 1 is good for reading while writing is a overhead for the disk
> and may hit the performance

Unless you are doing something (such as video editing) that relies on
ultra-fast hard drive access, you will probably never notice the
difference.  With hardware RAID, the performance hit will be even less.

> 2) Dont create RAID for swap and / root partition (Not Advisable)

Why not?  This defeats the purpose of the RAID.  You need to mirror all
filesystems to prevent data loss in the event of a hard drive crash. 
You need to mirror swap so that the system can continue running if one
hard drive goes.

> 3) Swap Size size should be 2X the size of the Physical memory

Not anymore.  These days, I would not allocate more than 16GB for swap. 
You shouldn't really need any swap.  Memory is cheap enough now that if
your system is using swap, you should add more memory.  Swap usage is a
serious performance hit.  Some people advocate running without any swap
at all.