[ale] raid with linux

Jeff Hubbs hbbs at attbi.com
Thu Nov 14 09:09:15 EST 2002


Well, two RAID 1 pairs like what you describe will take 520GB of drives
and give you half of that (260GB) back in effective disk space.   That's
a pretty hard hit in the cost-effectiveness solar plexus.

Also realize that any performance gain you try to get by using a decent
RAID card instead of kernel RAID will be eaten into by putting two
drives on per controller.  

There are lots of ways to arrange this, but I would say that if you are
going to try to get ~260GB of effective storage going, you can go for
cheap or you can go for speed.  

Cheap:
Kernel RAID 5
One dual IDE card
ide0:  boot disk (any size); 120GB drive
ide1:  CD-ROM; 120GB drive
ide2:  120GB drive

Effective: 240GB
Cost:  ~$510
Ratio:  $2.13/GB

Add another 120GB drive to ide2 for:
Effective: 360GB
Cost:  ~$676
Ratio:  $1.87/GB

Use four 80GB 5400RPM drives instead:
Effective: 240GB
Cost:  ~$396
***Ratio:  $1.65/GB*** # this is what I ought to do

Fast:
I'm not going to hunt up specs/costs for this for free :-) but suffice
it to say that you'd use one or more of the better IDE RAID cards set
for hybrid RAID 0+1 (or whatever it's called), four
fast-as-they-make-them 120GB drives or six 80GB drives (1:2 ratio in
this config), only one drive per cable.

- Jeff

On Wed, 2002-11-13 at 20:01, Christopher Bergeron wrote:
> Ok... So are there any recommendations?  I agree that hardware raid is 
> better than software (hence my lean towards a controller card).   I'm 
> going to be mirroring the drives (no RAID 5 or anything [yet]).  The 
> configuration is going to be as follows:
> 
> (I'm building a SAN/fileserver and I'd like the best "value" 
> [price/perfomance ratio].)  I'm essentially aiming for the apex of the 
> cost/benefit curve (isn't everyone?!).
> 
> 2 x 180GB IDE drives
> 2 x 80GB IDE drives
> 1 x whatever minimal system drive
> 
> As such, I was thinking about using a 20GB or whatever drive for the 
> OS/system and a promise controller (or other brand - recommendations are 
> welcomed) for the IDE drives.  I have 0 (pronounced: zero) experience 
> configuring RAID under linux and as such I'm looking for the most 
> painless way to proceed.  This is a fraction of the project that I'm 
> working on, and as such I don't want to spend too much time 
> tweaking/installing this setup.
> 
> Since the mobo can only handle 4 ide (2 pairs); I know that I'll have to 
> use a raid controller (I'm dismissing the raid motherboards that I've 
> seen at Ginstar and others).  I'm _very_ familiar with redhat and 
> Gentoo...  I'd like to make this a Gentoo box; but at this point the 
> distro isn't really relevant.  The box sits on the inside of our 
> network, and as such kernel versions and package versions can remain 
> static (if it works; why upgrade it [security aside]).  I won't be 
> upgrading the packages/kernel unless something comes up.  This machine 
> is intended to be a headless server.  As long as it works and serves 
> files, that's all I care about.
> 
> Your guys'es thoughts/recommendations?
> 
> Thanks again,
> -CB
> 
> 
> 
> Zack Link wrote:
> 
> > Might be limited to one distro (red hat for instance), and a certain 
> > kernel version for drivers for hardware raid.  I have an onboard RAID 
> > controller on a PC, and I am stuck with RH AND a certain kernel 
> > version.  No upgrading the kernel etc.  Maybe there is a way around 
> > it, but in the short time I worked on it, that was the only way I 
> > could get it to work.  This is pretty much because of closed source 
> > binary drivers I think.
> >
> > Anyway, something to be aware of when shopping for a hardware RAID 
> > controller.  Make sure there are available open source drivers.
> >
> > But, I always prefer hardware RAID to software RAID.
> >
> > ZL
> >
> >
> >
> > At 04:13 PM 11/13/2002 -0500, you wrote:
> >
> >> I need to setup a raid fileserver.  Here's what I'm wondering...  
> >> Should I get one of those Promise Raid controllers (IDE) or should I 
> >> do the raid with linux?  The machine will run linux and samba.  I'd 
> >> like to use the hardware solution, but I'm wondering if there are any 
> >> caveats that I should know about.  Anyone have any suggestions or 
> >> insights?
> >>
> >> Thanks,
> >> -CB
> >>
> >>
> >>
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> >
> >
> >
> 
> 
> 
> 
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