Don't forget there are tons of 1u's too. If rack space is expensive for
you because you use a datacenter somewhere, then 1u's with 1-4 drives
each might be good for you as well, if you're concerned with server
redundancy as well.
The limitation there is that you could only fit your raid card in it and
have to use on-board nics. 2u's are good, but not if you are charged
per/u(some data centers do that).
On Tue, 2001-12-18 at 15:41, Steve Wolfe wrote:
> > Thanks a bunch steve, your review was great...Now about Levels 1, how
> is
> > that a different matter? (Good/Bad/Etc)
>
> I was only talking about the benefits of hardware over software in
> certain levels, not the swapping or any other merits. : ) In RAID 5,
> the
> checksumming you need to do during writes is pretty substantial, and
> having it on a hardware card offloads that from the host computer's CPU.
> RAID 0 and 1 don't have the checksumming, so running it in software has
> a
> much, much lower impact on the host CPU. However, that means that if
> you
> have a truly wimpy processor on the RAID controller, that it can run
> very
> slowly. I've heard that's the case with the low-end 3ware IDE RAID
> cards,
> their processers can't handle the load of RAID 5 well. Supposedly, the
> higher-end cards have much better processors on them. The 3ware cards
> are
> targetted as a very-low cost RAID solution, and that has to be taken
> into
> consideration,
>
> > I found a couple 2U cases with
> > two hot swap bays on the front - which might be the most economical
> route
> > for having a drive redundancy for a server farm - rather than having
> one
> > shared storage for a number of servers.
>
> First, if you want the drives in the units, you might think about the
> BoomRack 2U series C (http://www.boomrack.com/html/2u.htm), it will give
> you *4* hot-swappable bays on the front of a 2U chassis. I've used
> their 4U racks, and am very impressed with them. I'll be trying out
> some
> of the 2U's some time in the future, just not right now. : ) If you buy
> them, try to get them from a reseller. BoomRack charges a LOT if you
> buy
> directly from them, in order to promote purchasing them from a reseller.
> A 4U chassis that's around $400 direct from them may only be $230 or so
> from a reseller.
>
> Second, having redundancy in the machines is certainly good to promote
> uptime, but centralized storage also has it's benefits. Backups,
> especially, come to mind. Doing nightly backups of multiple machines
> acrosss a network sounds like a very time-consuming process. I much
> prefer to have the DAT/tape/whatever in the file server itself.
>
> To go even further, it's certainly possible to eliminate the drives
> from
> the servers entirely! If you wanted, you could either boot from the
> network, or to a flash-drive, use a RAM drive for /tmp, and mount
> everything else from the file server. In some situations, that works
> well, in others, it's not what you want - but it does certainly promote
> uptime at a low cost, avoiding having to buy the drives, RAID
> controllers,
> and special chassis for each of the front-end servers. Or, if you're
> lucky enough to have a load-balancer with automatic failover, you can
> just
> stick a cheap IDE drive in each machine, and forget about it. If you've
> bought decent IDE drives, once every few years, you'll notice that one
> machine is out of the rotation, and have to go work on it. ; )
>
> > I'm definately looking at a
> > hardware based solution, I actually want to use the same boxes for a
> > couple FreeBSD machines a client is going to need as well. Between
> > mirroring and parity, how do the hotswaps compare?
>
> I haven't used mirroring, but from my understanding, it should work
> smoothly in hardware, and in software, can have it's drawbacks. The
> beauties of hardware RAID (to me, at least) are offloading the
> processing
> from the host CPU, having onboard cache, and that it's a lot closer to
> "plug and play".
>
> steve
--
Austin Gonyou
Systems Architect, CCNA
Coremetrics, Inc.
Phone: 512-698-7250
email: austin@xxxxxxxxxxxxxxx
"Have regard for your name, since it will remain for you longer than a
great store of gold."
Ecclesiastes, Aprocrypha
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