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Re: HP proliant ML115 G5 on debian lenny



On Fri, Apr 24, 2009 at 02:10:41PM -0400, Douglas A. Tutty wrote:

Thank you very much for your reply!

> Well, debian has different requirements re licensing of modules.  Your
> guess may be wrong if HP has provided a propriatary module for the
> kernel that e.g. suse has included in its kernel but debian can't
> include.  For some things (e.g. the nVidia driver), you can still get an
> install done and add a module later; for the boot drive that becomes a
> bit of a problem :)

My plan is to use the 250G harddrive as system drive and use 2x1T
dardrives to do RAID 1 backup for several other servers. So what do you
mean by 'for the boot drive'? 

> 
> So-called 'fake' raid is, as I understand it, hardware that allows you
> to configure the raid in the bios, but the actual raid happens in
> windows software rather than in the hardware.
> 

Could you please explain 'in windows software' a little bit? Does that
means the processing for raid is done in CPU rather that in the RAID
controller?

> > And the server will merely be used for backup.
>  
> A couple of issues then.  
> 
> 1.	Performance may or may not be an issue, depending on how many
> 	other computers will be using the server for data backup at the
> 	same time.  

three linux servers(1 development server 1 mail and web server and 1
misc server) will be backing up their data to the back up server I
purchase.

> 
> 2.	With hardware raid, unless the raid card can save the
> 	configuration to each disk in the array, if something happens to
> 	the card (which could happen if a drive fails and takes down the
> 	controller), then the whole array could be caput if you put in a
> 	new controller card.

So this must be the downside of using hardware RAID?

> 
> 3.	With software raid, the configuration is on the disk itself.
> 	Pop those disks in a new box and they should work (assuming that
> 	the new box's hardware can be booted by the old box's initrd).

This is great!

> 
> 4.	Hardware raid comes into its own with exotic raid types (e.g.
> 	raid50 or raid60), with hot spares, hot swap, auto rebuild, etc.

I will only use raid 1, that is because this is simple and effective as
it appears.

> 
> 5.	There has been some talk recently here on the increased
> 	liklyhood of raid failue after a single drive failure.
> 	Apparently, the time it takes for a replacment second drive to
> 	rebuild makes the liklihood of the other drive failing before
> 	the rebuild is complete of some concern with very large drive
> 	sizes.  In this case, having three active raid1 drives with a
> 	hot spare (4 drives total) is one way to mitigate this risk.

This is alarming, I will do more research to come up with a plan.

> 
> You may need to do lots of research depending on:
> 
> 1.	The size of your backup set

I will do a careful check and estimate later on.

> 
> 2.	The importance of the data

mailing list archives, web data, database, svn repos.. home
directories.. They are very important and I can not afford to lose any
of them.

> 
> 3.	The number of locations of the backup data.
> 

What do you mean by this? Is it ok to put all of the backup in one
backup server?

Again, Thank you very much!

Regards,

-- 
Zhengquan


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