I'm brainstorming a new server.. i've decided to go with a 12 drive
case for this one.. which means the 8 port pci-e 3ware card now needs
to be a 12 port..

But.. this motherboard
http://www.atacom.com/program/print_...&USER_I D=www
already has 6 sata and raid5 and raid10 ability...

Would it be a bad idea to use the onboard one for the extra 4 drives?

This server will house 3 sql instances, file serving, antivirus
central server, but the user base is 40 and 2 of those sql instances
are low hit rates.

Would i see that much more performance for the extra $250 it would
cost to put them all on the same card.. or in fact.. might it be
better just to split them up in fact.

Thanks for any input here.

Previously markm75 <markm75c@msn.com> wrote:
Depends on your access patterns. On-board ''RAID'' is typically
fakeRAID. It is not faster than software-RAID, but less flexible
and if the board dies you may have a recovery problem.

If you are satisfied with the 3ware controller's performance but
need 12 RAIDed disks, I would advise you to get a 12 port
controller. Otherwise put a true software RAID on the remaining
4 disks.

Arno

markm75 wrote:


"This is for random operations with small block sizes. At large block sizes,
the Mtron
drive is 10-40% faster than a 15K SSD, mostly depending on what part of the
HDD
you are accessing."

Think you aught to currect this part... "15K SSD" ??

I think great stuff otherwise. SSD's have to go into RAID systems, think so
to, nice to see someone agreeing on this.

Any thoughts about RAID 6, is it needed on SSD's, large HDD 144GB+ yes but
large SSD - think rebuild time aught to be lower with SSD ??

Previously lars <lars@hesdorf.dk> wrote:

SSDs are close to computer memory. Adding an external RAID layer to
them sounds like a very wrong thing to do to me. Any redundancy
should be done in teh SSD itself.

Arno

Arno Wagner wrote:

You know that in high end IBM and other servers RAID 1 for the memory is
availably.

And come to think of it there is still the problem of FRU if doing the
redundancy in the SSD itself. So for real life in a sever, no sir RAID
still has its advances - otherwise 24x7 can't be done.

Previously lars <lars@hesdorf.dk> wrote:
RAID for memory? Are you sure you are not talking about ECC,
which is far better for memory? I do not expect this type of really,
really bad engineering out of IBM, unless the customer demands
it (due to incompetence). Care to list a reference?

RAID is fine. But RAID for SSDs is just a sign that the technology
is not being understood. The problem here is that while HDDs
a) typically fail as a unit and b) typically notice when they are
failing, RAID makes a lot of sense with HDDs. SSDs are more likely
to fail in memory locations. A quality SSD can compensate with ECC.
If it cannot, then its controller chip is shot )or something very, very
unlikely happened) and it may give arbitrary wrong data to the
user. RAID does not help at all in this case. Of course this is
simplified.

Arno

Arno Wagner wrote:

YES sure!

Go to www.ibm.com do a search for "memory mirrored" you will among other
things find xSeries models and tech papers on this.

http://researchweb.watson.ibm.com/jo.../tremaine.html
and many many other.

Still won't do in real life, SSD simply can't be sold as a "never failing
single device". There is no market in highend IT for such a thing!
A solution with the possibility of handling the SSD as a FRU is what it
takes - without question.

Not that I like refering to specific products, but this company I think is
close me my own thinking and the use of SSD's.
http://www.bitmicro.com/solutions_apps_comp_raidsys.php

Now...
Please take a good cup of coffee, and sit down for a while.

Having great new technology coming to market, is well... great :-)
But if 24x7 handling can't be given, then the new technology will have no
place in high end solutions. Solution keeps running while having failed
part replaced is what defines highend storage today - I think.

SSD will be banned to live its hole life in laptops etc.
And "never failing single device" well not good enough for highend storage
solutions..

So even if you are right SSD "technology is not being understood", you have
to understand the storage market better I think.
So to put it as clear as I can, even if you beeing right today about SSD it
will take years (decades) before you could sell such stuff to highend
without extra security.

Arno Wagner wrote in news:5rvblsF15ut1dU2@mid.individual.net
Hard of hearing now too, babblehead?

Like you yourself are 'simple', babblehead.

Previously lars <lars@hesdorf.dk> wrote:
Ok, that is for very high availability stuff only. And it is
not RAID in thst strict sense. It is mirrored memory that can
continue to operate through ECC failure. Unless the controller
and bus system is orders of magnitude more reliable than the
memory used, this makes no sense at al technologicaly.


I never vclaimed that. But I expect a SSD is as reliable as the
disk controller in the first place and reduyndancy by multiple
SSDs makes no sense.

See above.

Not at all. I am not in the business of ripping customers off. I am a
customer that is an expert at the same time. As with the memory,
redundancy by having multiple SSDs only makes sense if the RAID
controller used is orders of magnitude more reliable than the SSD. I
doubt that is the case for typical SSDs and controllers. For HDDs it
is routinely the case.

a) It is "safety" or "redundancy", not "security".
b) People buy all kinds of stupid stuff, because they do not understand
science and/or engineering.
c) A pair of high-reliability SSDs,
together with a high reliability RAID-1 controller is actually
less reliable than using one of the SSDs directly, if we assume
that a simple non-RAID controller is a lot more reliable. Do the
math. The assumption has merit, because the RAID-1 controller is
much more complex than a simple controller.

Arno

Arno Wagner wrote:


I know clustered OS has come around to stay. But still being able to run
until next service opportunity to replace memory, great stuff if you really
need it.


Arno Wagner wrote:

No No disk controller. Highend. Eg. HDS 99xx systems - Doing 7D+1P uses 8
disk controllers, so also the disk controller can be replaced as FRU with
running disk system. In each array each disk only uses a given disk
controller for one disk in the array. Each disk controller then beeing used
for many disk arrays.
Think IBM highend disk systems, 8300 (and lower), as well.

And yes disk controllers they do fail.

Previously lars <lars@hesdorf.dk> wrote:
No. You can mirror without Redundant Array of Inexpensive Disks.
Memory redundancy is not RAID at all, except for two instances
of the memory being there.

Unless it is just expensive and does not improve overall
reliability. You know the more eleaborate memory controller has
a higher chance to fail. And you cannot replace that in a running system,
now can you?

And the redundancy is done on what level here? Software-Raid?

Arno

Arno Wagner wrote in news:5s4q63F17kilvU1@mid.individual.net
The very same can be said of RAID1.
Yet that is what they call it even though it's not much of an "array".

Who said anything about there being one controller.

How about the OS, babblehead moron.

Arno Wagner wrote in news:5s3qnpF17afveU1@mid.individual.net
Yeah, nothing to do with RAID obviously.

Of course not. Everyone and his dog knows that.

Yeah, obviously a whole other ball game.

Yeah, who cares about the rest.

Who sayd they must be on the same controller, babblehead.

Coffee is all there is in the babbleheads veins.
That's what allows it to bullshit at all hours of the day and night.

Idjut.

It doesn't need to be a RAID controller, you babblehead moron.

Pity security is just another word for safety.

Bwahaha.

Utterly clueless, as always.