Software RAID (was Re: [TriLUG] Music Files)

[Joel Ebel]

That doesn't apply to SATA since SATA only allows a single drive per 
cable.  Of course the entire card can fail, but if all drives are 
attached to the same card they should fail simultaneously keeping the 
data in tact.  You mention RAID 1.  Just to elaborate, if you used RAID 
1 with two drives on the same IDE cable and one went bad, the data would 
probably still be ok on the second drive, you just wouldn't be able to 
keep operating the system.  So data preservation is hopefully still 
effective, but availability is lost.

Joel

Tanner Lovelace wrote:
> On 5/24/05, Joel Ebel <jbebel at ncsu.edu> wrote:
> 
>>The most important thing for you to do if this is the only copy of them
>>all, is set up RAID.  You should read the software RAID Howto.
>>(http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html)   For such a large
>>volume of data, you'll want to use RAID 5.  You can use 3 250 GB disks
>>and have it be really tight, or you can have some room for expansion and
>>use 4 disks of 180 GB or more.  Make sure you read and understand the
>>HOWTO so you know how it all works.  You'll want to make sure each drive
>>in the array is on a separate bus if you're using IDE.  If two drives
>>are connected to the same IDE cable and one drive goes down, it will
>>likely take down the other drive connected to that cable as well.  RAID
>>5 can't handle the loss of multiple disks, so you would have a hard time
>>recovering your data.  Most computers with just one IDE bus will require
>>a separate IDE controller card to make a quality RAID 5 array.  Many
>>distributions will help you automate the process of setting up a RAID,
>>but you should understand what's going on so you can properly set it up,
>>monitor it, and recover from it if something happens.  I don't think the
>>automatic RAID tools account for things like the IDE bus issue mentioned
>>above which is why you need to understand what you're doing.
> 
> 
> Joel,
> 
> Do you have any information on whether the above (needing to
> have different drives on different IDE buses) is true for SATA too?
> I have a software RAID 1 setup on my home machine using 2
> 160GB SATA drives and have been wondering what things can 
> affect it.
> 
> Thanks,
> Tanner