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Re: Software RAID 5 or something else?



aragonx dcsnow com wrote:
Hello all,

I had a drive failure a few months back so I decided it was time to rework
my home server's storage.

Now I have 5 750GB SATA dives and now I need some advice on how to set
things up.

My original idea was to put them in a RAID 5 configuration.  This sounded
good until I started researching RAID controller cards.  It looks like it
will cost me $520 to get a good PCI-E card (3Ware 8 port).  I don't think
I want to spend that much if I don't have to.

My goals are two fold.

1) I want to get some redundancy in case of a drive failure.

2) I want to increase my performance.  I have benchmarked my read and
write performance to and from this server.  Using Samba, I seem to be able
to get about 50Mb/sec reads and 40Mb/sec writes.  I am on a gig network
and would like to be able to max out the cards (90Mb/sec is what I get at
work).

So, the question is, what should I do?

1)  Bite the bullet and get the hardware RAID controller.  Will this give
me the performance I want?

2)  Go with a software RAID 5.  Will I lose performance with this
configuration?  If I use this but only get modest performance gains, that
would be acceptable.

3)  Go with some other software RAID level.

Any help would be appreciated.

---
Will Y.




If you understand that there is really no such thing as hardware based RAID.

There is 'dedicated hardware' based RAID, which is software based RAID on a card that does nothing else but RAID.

Most of these RAID cards have a small, slow, CPU, and relatively slow RAM modules to run the RAID software.

So considering that, what do you gain from dedicated hardware for RAID? You get a commercially supported RAID software and hardware package, and you get to unload a bit of CPU from the main system.

Considering that the CPU on the card at max performance is probably 1/3 of a core from a modern CPU, then that is not really much of a savings.

The real consideration for RAID 5 is survival. In either situation you have to have a spare drive, and you have to consider availability of new drives to match them in the future.

Good Luck!


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