TCLUG Archive
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [TCLUG:22757] Raid and other storage stories
Ok, time to veer this another direction (grin).
When RAID controllers are writing to the drives, are they
doing it in any standard fashion? For example, if I buy a
Mylex Acceleraid 150, and in five years it burns out,
will I need a Mylex Acceleraid 150 to read the data from
the drives?
Kent
Nick.T.Reinking@supervalu.com wrote:
>
> Ahh, coolness.
>
> In response to CPU Util, recently, IDE drives have had
> lower CPU util than SCSI (because of DMA). It's mostly
> a driver issue, and the amount of CPU util is just a few
> percent, anyways.
>
> However, software RAID will seriously hurt your CPU Util.
> The Escalade does the IDE RAID in hardware, so it only
> uses a few percent of CPU to do your RAIDness.
>
> Nick
>
> jasonj@innominatus.com, on 10/17/2000 02:37:10 PM
> To: tclug-list@mn-linux.org @ PMDF
> cc:
> Subject: Re: [TCLUG:22757] Raid and other storage stories
>
> No, RAID 10 is striped parity information. Similar to RAID 5 that has a
> dedicated
> drive for parity informaiton. RAID 10 stripes the parity across all drives. If
> one
> drive fails, the replacement drive is rebuilt with the parity info from the
> other
> drives. I think there is more performance than RAID 5.
> 0+1 is not 10. 0+1 is 2 drives striped, and 2 more mirroring the stripe.
>
> Nick.T.Reinking@supervalu.com wrote:
>
> > RAID 10 == RAID 0+1.
> >
> > The difference is that the Escalade does it in hardware,
> > whereas the FastTrack and HighPoint do it in software.
> >
> > Nick
> >
> > jasonj@innominatus.com, on 10/17/2000 01:53:33 PM
> > To: tclug-list@mn-linux.org @ PMDF
> > cc:
> > Subject: Re: [TCLUG:22757] Raid and other storage stories
> >
> > Escalada 6xxx does RAID 0, 1, and 10
> >
> > Fasttrak does 0, 1, and 0+1
> > Highpoint does 0, 1, and 0+1
> >
> > Nick.T.Reinking@supervalu.com wrote:
> >
> > > Try www.elinux.com or www.thelinuxstore.com.
> > >
> > > Also, you don't need ATA/100 at all with just one device.
> > >
> > > As cool and fast as those 75GXPs are, they're not going to top
> > > more than 40MB/sec. Easily under 66MB/sec.
> > >
> > > AFAIK, you can do all the weird partitioning that you could do
> > > with a real SCSI RAID controller. The only bad thing about them
> > > is that they don't support RAID 5. Only RAID 0,1, and 0+1, and
> > > JBOD, I think.
> > >
> > > Nick Reinking
> > >
> > > dopp@acm.cs.umn.edu, on 10/17/2000 01:14:41 PM
> > > To: tclug-list@mn-linux.org @ PMDF
> > > cc:
> > > Subject: Re: [TCLUG:22757] Raid and other storage stories
> > >
> > > On Tue, Oct 17, 2000 at 12:54:46PM -0500, Nick.T.Reinking@supervalu.com
> wrote:
> > > > The Escalade 6xxx series support ATA/66.
> > >
> > > Well, maybe they have an ATA/100 version planned...
> > >
> > > >
> > > > They're really cool...
> > >
> > > They look cool...
> > >
> > > >
> > > > 2-8 channels, 1 device/channel (which is why ATA/66 is
> > > > plenty good). It's completely internal.
> > >
> > > Internal is good. I have a full tower, so I'll have the room.
> > >
> > > >
> > > > The 3ware driver makes any RAIDed drives look like a single
> > > > SCSI drive.
> > > >
> > > > Furthermore, the 3ware supports other cool things such as
> > > > command queueing, etc. Plus, they have an onboard co-processor.
> > > > (same one most SCSI RAID cards have).
> > >
> > > How about logical partitioning? Does the Escalade allow me to make, say, 4
> > > drives into a single logical drive and then partition that logical drive
> > > into say, 3 logical partitions which all appear as seperate drives to my
> > > machine?
> > >
> > > The reason I ask is because I was thinking about the following setup:
> > >
> > > 4 30GB ATA/100 Deskstars
> > > 1 logical drive
> > > 2 logical partitions
> > >
> > > I suppose I could just take the 1 logical drive and partition it through
> > > the OS, but if the controller handles it for me, it's that much nicer.
> > >
> > > >
> > > > The FastTrack card is both poorly supported, plus it doesn't
> > > > have a co-processor. All it does for you is make your RAID
> > > > drives look like one drive. It's still all software otherwise.
> > >
> > > Ah, thanks for the heads-up.
> > >
> > > >
> > > > >From what I've heard, these cards are pretty amazingly fast.
> > > > IDE is faster than SCSI for one device, since the command
> > > > set is much smaller (and faster). Since there is only one device/channel
> > > > on this controller... well, it's pretty amazing. Plus, it has an
> > > > Alan Cox approved open source driver in 2.2.15+.
> > > >
> > >
> > > Eenteresteeng... I'll have to give it a try. Where do you suggest I get
> > > one of these controllers? It looks like one can only buy them through
> > > offical 3ware resellers.
> > >
> > > Gabe
> > > --
> > >
> >
> --------------------------------------------------------------------------------
> > > Gabe Turner | X-President,
> > > UNIX Systems Administrator, | Assoc. for Computing
> > Machinery
> > > U of M Supercomputing Institute for | Univerisity of Minnesota
> > > Digital Simulation and Advanced Computation | dopp@acm.cs.umn.edu
> > >
> > > "Dear Dr. Stupid: Why do I have to go to school?" -- Announcer
> > > "Your parents are aliens!! While you're at school, they shed their
> > > human skins and breathe dryer lint!!"
> > > - Dr. Stupid in "Ask Dr. Stupid"
> > >
> >
> --------------------------------------------------------------------------------
> > >
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> > > For additional commands, e-mail: tclug-list-help@mn-linux.org
> > >
> > > ------------------------------------------------------------------------
> > > ---------------------------------------------------------------------
> > > To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> > > For additional commands, e-mail: tclug-list-help@mn-linux.org
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> > For additional commands, e-mail: tclug-list-help@mn-linux.org
> >
> > ------------------------------------------------------------------------
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> > For additional commands, e-mail: tclug-list-help@mn-linux.org
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> For additional commands, e-mail: tclug-list-help@mn-linux.org
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tclug-list-unsubscribe@mn-linux.org
> For additional commands, e-mail: tclug-list-help@mn-linux.org
--
Kent Schumacher
Structural Wood Corporation
4000 Labore Rd.
St. Paul, MN 55110
Phone: (651) 426-8111
Fax: (651) 426-6859
e-mail: kent@structural-wood.com