[K12OSN] Raid Level Choice

Liam Marshall lsrpm at mts.net
Wed Dec 22 16:38:58 UTC 2004


Les Mikesell wrote:

>On Wed, 2004-12-22 at 09:58, Liam Marshall wrote:
>
>  
>
>>Question is, which way is better, 5 or 10?  or does someone prefer 
>>something else
>>    
>>
>
>RAID5 causes a big hit on write speed and most systems are also
>very slow in degraded mode when you continue to run with a failed
>drive.
>
>If you can afford to lose half your disk space (and with IDE/SATA
>that's no longer a big expense), using RAID1 will give better
>performance.  Then you need to consider the tradeoffs for mounting
>each RAID1 device as a separate partition (pro: you can recover
>data from a single drive - con: inflexible disk space layout), vs.
>combining them in a fixed combination with RAID 0 + 1, vs. running
>LVM to merge the space.  If I had a reasonable backup system working
>so the disaster recovery scenario didn't matter, I'd lean toward
>LVM over RAID1 pairs, especially if starting fresh with FC2/k12ltsp4.2
>which defaults to LVM in the installer.
>
>---
>  Les Mikesell
>    les at futuresource.com
>
>
>  
>
and if I was considering raid for my disaster recovery option?  I don't 
really have a back up option other that a script I use to copy files 
from the server onto my laptop's hard drive, then burning.  This of 
course plays havoc with permissions etc. and is not a good solution, 
just a solution.

I don't have 6 drives, so 50 etc is out.  But between 5 and 10 which 
provides better performance while still giving reasonable disaster 
recovery?  In my environment, there is more reading than writing  and I 
am teaching office applications which on the whole are small files, 
except for Presentation files

I just downloaded and burnt the iso for 4.2.0 rc1 (what does rc1 stand for?)

I have a SATA raid controller that will do hardware raid.  Can you 
explain why I might want to use LVMs instead?  I think that is what you 
are suggesting




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