[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Using RAID chipsets in the motherboard. - yup




hi ya alex

On Tue, 30 Dec 2003, Alex Malinovich wrote:

> On Tue, 2003-12-30 at 12:49, Alvin Oga wrote:
> --snip--
> > 3ware (raid cards) has readily available and easily understandable raid
> > drivers for their cards
> > 
> > hw raid -- you're stuck with what they give you for driver support
> >    and monitoring
> > 
> > sw raid .. do what you like to your hearts content ..
> 
> I've been using a 3ware board for a while now with no problems. The
> kernel drivers for it are GPL'd, so you're not really 'stuck' as long as
> you don't mind doing some kernel hacking. :)

yup... i use 3ware raid cards too if one wanted an "inexpensive" hw raid
( personally, i prefer sw raid )

> > > 3) My need for using these controllers is to have the ability to add extra disk
> > >    and I do not need their RAID features.
> > 
> > neither hardware/software raid does not lend itslef too easily to "expand
> > your raid" to larger capacity
> > 	- you cannot merely add a disk 
> > 
> > 	- you have to have a resizable partition and resizable fs to "add
> > 	a new disk" to add mroe capacity to your 100% full raid subsystem
> 
> If all you want is to be able to enlarge the array at any given time,
> your best bet is to just use regular old IDE/SCSI drives and boards. I
> believe you can tack on drives to a JBOD array, but I'm not sure.

my $0.01 is that one can't just add a new expansion disk to a raid0 array
... since one formats it to get it started

> Personally, I use RAID since I can't afford SCSI but still need really
> good performance.

yes.. raid can get you faster performance ...
 
> > raid is too much trouble for the benefits one gets
> > 
> > - you want raid iff ..
> > 	- you cannot afford for that data to go offline
> > 	- you have the $$$ to have a 2nd raid backup system
> > 	- you can sync data correctly from raid1 to raid2
> > 	- you lose more $$$ in being offline than you would be manually
> > 	rebuilding a new disk and restore from backups
> > 
> > 	- you want to protect your system against one disk failure
> > 	and you know what the mtbf is for your cpu, memory, fans, disks, 
> > 	and general user admin boo-boos and go offline anyway
> 
> RAID is also good if you need better performance than offered by regular
> IDE disks. RAID10 will give you excellent backups at speeds comparable
> to RAID0.

yuppers.. 

done one stripe and than mirror or mirror and than stripe ..
	( mirror than stripe is better )

differences in raid
	http://1U-Raid5.net/Differences

> > you can have up to 12 (ide)disks in a raid subsystem
> > and even mroe in scsi based raids
> > 	- i dont know of anybody with more than 12 ide disks in their raid
> > 	or willing to play with that much data in an untested manner
> > 	- you'd be on the bleeding edge at more than 12 ide disks
> 
> If you're going to use more than 12 disks, you'll need a dedicated
> enclosure. And if you can afford one of those, you can also afford SCSI
> disks, in which case you can have a nice 10+ disk SCSI RAID array with a
> hot-swappable external enclosure. That's bleeding edge. (The pricetag
> will also make your eyes bleed though...)

bleeding edge is fun stuff .... 

and even more fun to use dual-host raid so that either cpu can get
to the raid array  ( looks like 25yr old technology is coming back )

c ya
alvin




Reply to: