RAID 5 Performance as Main Drive

I have several 750GB HDs and planning to RAID them. If I do a RAID 5 and use that as my main drive would I suffer any performance or any other issues. I know the read will be slower than doing a RAID 0 but if do a RAID 5 over at least 4 drives can this be compensated? What number of drives would be the best to use or is it just best to do a RAID 0 with one set and RAID 5 the leftovers?

I'd really appreciate the help. Thx.

you will need a nice little expensive RAID controller to get decent performance. And I can't really recommend doing RAID 5 with SATA drives. Might as well stick to raid 0 unless your gonna invest in SAS drives.

Thanks for the response but why wouldn't you recommend RAID5 with SATA drives?

And I can't really recommend doing RAID 5 with SATA drives.

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Why not?

if you have a good controller the performance will be fine.

Does the ICH10R chipset qualify as a good controller?

TheCheat said:

Does the ICH10R chipset qualify as a good controller?

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Boy, you really opened up a can of worms with that question

I'm not a fan of Matrix RAID on the ICHxR chips, but that's me . RAID-0 on ICH, sure. RAID-5 on ICH, I'll pass. But to answer your question, I have a Vista NAS that runs a hardware based (Areca ARC1220) RAID-6 with (7x) 750GB Seagate 7200.11's (PC#3 in my sig).

I initially had a 36GB Raptor as my OS Drive. I decided to make a 50GB RAID-6 partition for my OS, and ditch the raptor. Obviously, as a NAS, this PC doesn't really tax the OS HD for bandwidth, but I really don't notice that it boots much quicker to be honest. I do love RAID-0 Raptors for OS Duties in my main Desktop, though .

I get approx 250MB/s sustained average writes and about the same sustained reads (using Diskmark10 set to 1GB test sizes and also with ATTO Bench set to 256MB Test Size). Needless to say it EASILY saturates my Gigabit LAN at ~960mbps (over 100MB/s sustained transfers) .

I'd say try it and see if it is worth it TO YOU. You will also have the security of Data Redundancy carried across to your OS partition...

yes raid 0 / raid 1, okay but raid 5 and such will use more cpu cycles as there is ALOT more going on, i would prefer a separate raid controller.


raid 6 isn't fast and is in fact i recall about %30 slower then raid 5, it just offers up to 2 drive failure, raid 6 is not for any level of performance, simply more redundancy.

250MB Reads/Writes ain't fast? That's what I get with my Areca RAID card in RAID-6 (PC#3 in my sig). I'd say that is pretty fast . My Raptor RAID-0 Array in PC#1 doesn't even get those kinds of writes (but of course has lower access times). Yes, RAID-5 is faster, but RAID-6 "ain't no slouch" on good hardware...

A perfect balance of uber-redundancy AND speed, but you get what you pay for at this level. I also run a 4-Drive RAID-5 in PC#1 (4x 1TB 7200.11's on ARC1210), but I don't boot from it, so I couldn't comment on its use as an OS drive . But the 4-Drive RAID-5 is almost as fast as the 7-Drive RAID-6, so you are correct that RAID-6 is not as fast as RAID-5 (but I still wouldn't call RAID-6 "Slow" by any means)...

Thanks a lot for the help guys. It looks like that I need to avoid RAID 5 without using a hardware controller. I think I will just leave that to when I decide to make a server. I got advice to do a RAID 0 and a RAID 1 with four drives so I have my speed with 0 and backup w/ 1.

I noticed you guys posting your speeds. Do you guys know a site and program likewise where I can find out what averages are so I can find when I do my system setup I can compare and see whether or not I like the matching results or not? Just for your info I am using 4 WD-RE2 GP.

Thanks again for the info.